Advances in Genetics, Breeding, and Quality Traits in Forage and Turf Grass

A special issue of Agronomy (ISSN 2073-4395). This special issue belongs to the section "Grassland and Pasture Science".

Deadline for manuscript submissions: closed (30 June 2023) | Viewed by 33225

Special Issue Editors


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Guest Editor
College of Grassland Science and technology, China Agricultural University, Beijing 100193, China
Interests: genetic improvement of forage and turf stress resistance; biomass yield and forage quality; legume–rhizobium interaction
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
College of Agro-Grassland Science, Nanjing Agricultural University, Nanjing, China
Interests: turfgrass physiology; climate change; abiotic stress resistance; turf grass breeding
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues, 

In recent years, much progress has been achieved in the areas of forage and turf grass genetics, functional gene identification, and modification of important quality traits via direct genetic transformation. Recently, the genome sequencing of several important forage and turf grasses has been completed. With the techniques of transcriptomics, proteomics, and metabonomics, many potentially important genes and metabolic regulatory pathways have been suggested or illustrated. To summarize the latest research findings, the Special Issue will encompass the following topics:

  1. Development key molecular markers on important quality traits for marker assistant breeding;
  2. Gene functional identification on important quality traits, such as stress resistant, biomass yield, forage quality, and so on;
  3. Development of fast breeding techniques, such as CRISPR-Cas9 genome editing technology;
  4. The molecular mechanisms of grass important trait formation.

Authors are invited to submit original research articles, review articles, opinion papers, and short communications.

Dr. Wanjun Zhang
Dr. Jingjin Yu
Guest Editors

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Keywords

  • turf grass
  • forage grass
  • functional gene
  • stress resistance
  • quality trait

Related Special Issue

Published Papers (19 papers)

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Research

14 pages, 2051 KiB  
Article
Wild Oats Offer New Possibilities for Forage Because of the Higher Nutrition Content and Feed Value
by Jieyu Zhang, Xiaolong Li, Junzhen Wang, Li Yang, Qiaohui Yang, Dabing Xiang, Yan Wan, Eviatar Nevo, Jun Yan, Yu Fan and Liang Zou
Agronomy 2023, 13(10), 2575; https://doi.org/10.3390/agronomy13102575 - 7 Oct 2023
Cited by 1 | Viewed by 1329
Abstract
Oats (Avena sativa L.) are mostly used as a germplasm resource for forage. This experiment showed the differences in the nutrient composition and the forage quality of five wild leather oat populations from Israel and one cultivated leather oat population from China. [...] Read more.
Oats (Avena sativa L.) are mostly used as a germplasm resource for forage. This experiment showed the differences in the nutrient composition and the forage quality of five wild leather oat populations from Israel and one cultivated leather oat population from China. It also showed the correlation of the indicators with the geo-environmental factors in the places of origin of the six populations that were analysed. Three replicated experiments were conducted during a three-year period from 2018.10 to 2020.03, mainly from 11 indicators of nutrient composition and forage quality. In this experiment, Spearman’s correlation was used to analyse the differences between different groups (p < 0.05), the relationship between components was analysed by principal component analysis (PCA), and the kinship relationship between six groups was also analysed based on the data of 11 components. In terms of nutrient content, the cultivated group Hu had significantly lower ash (8.92%), crude protein (11.96%), and soluble sugar content (10.51%) than the wild oat groups. In terms of forage quality, the lignin content (3.31%) of the Hu population was 2.3 times higher than that of Evolution Canyon, and the fibre content was 8 times higher than that of Sede Boqer. This indicates that wild oats have better nutritional value and palatability. Following the correlation analysis, it was found that the environmental factors of the origin had a significant effect on the indexes of ash, crude protein, and soluble sugar of oat straw, but had less effect on the content of crude fat, total phosphorus, and total potassium. Meanwhile, the annual rainfall and the number of rainfall days in the origin had a significant effect on the fibre content. In conclusion, the higher variability of wild oat populations due to the influence of different environmental and geographical factors may be a new possibility brought by forage oats. Full article
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12 pages, 1788 KiB  
Article
Determination of Feed Yield and Quality Parameters of Bermudagrass (Cynodon dactylon L. (Pers.)) Populations Collected from Natural Flora
by Sedat Severoglu and M. Kerim Gullap
Agronomy 2023, 13(6), 1471; https://doi.org/10.3390/agronomy13061471 - 26 May 2023
Viewed by 1321
Abstract
A two-year study (2020–2021) was conducted in the Erzurum province to investigate the feed quality parameters of 102 genotypes of Bermudagrass (Cynodon dactylon) collected from different locations in natural flora. Two control cultivars were also examined in this study, namely Coastal [...] Read more.
A two-year study (2020–2021) was conducted in the Erzurum province to investigate the feed quality parameters of 102 genotypes of Bermudagrass (Cynodon dactylon) collected from different locations in natural flora. Two control cultivars were also examined in this study, namely Coastal and Survivor. Parameters such as the fresh herbage weight, dry herbage weight, crude protein (CP) ratio, acid detergent fiber (ADF) ratio, neutral detergent fiber (NDF) ratio, and relative feed values (RFVs) were analyzed. In the first year of this study, Bermudagrass populations collected from natural flora were rooted in pots under greenhouse conditions. In the second year, the rooted plants were transplanted into experimental fields at the Atatürk University Plant Production Implementation and Research Center. The present genotypes generally had superior crude protein, ADF, NDF ratios, and relative feed values (RFVs) than the control cultivar. The fresh herbage weights ranged from 9.20 to 95.37 g per plant, while the dry herbage weights varied from 5.22 to 45.24 g per plant. The findings of this study showed that most of the genotypes collected from natural flora had superior feed quality parameters to the control genotypes. Full article
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16 pages, 3827 KiB  
Article
Core Germplasm Construction Based on Genetic and Phenotypic Diversity of Buffalograss (Bouteloua dactyloides (Nutt.) Columbus) from the Great Plains of America
by Yongqiang Qian, Manhua Jiang, Bokun Zou and Deying Li
Agronomy 2023, 13(5), 1382; https://doi.org/10.3390/agronomy13051382 - 16 May 2023
Viewed by 987
Abstract
Buffalograss is a valuable forage and turfgrass species native to the Great Plains of America. Utilization of genetic resources and conservation of germplasm rely on effective methods to differentiate and identify genetic differences quickly and at a relatively low cost. The lack of [...] Read more.
Buffalograss is a valuable forage and turfgrass species native to the Great Plains of America. Utilization of genetic resources and conservation of germplasm rely on effective methods to differentiate and identify genetic differences quickly and at a relatively low cost. The lack of correlation between DNA marker-based genetic diversity and the geographic distance in buffalograss indicates that the interaction between genotype and environment needs to be evaluated. The objective of this study was to establish a core collection of buffalograss germplasm based on SRAP, then solidify the construction with important phenotypic traits. A total of 143 accessions were collected from 16 regions in 10 states of the U.S. A total of 1033 bands were scored from the 10 combinations of forward and reverse primers, of which 1031 were polymorphic within the accessions. After evaluating multiple clustering approaches, we determined that using symmetric distance (such as DMATCH, SM) in the hierarchical Ward’s method was the best clustering method, resulting in five groups. A least distance stepwise clustering approach using the simple match similarity coefficient was most efficient in creating core collections. Adding the phenotypic information and a final core collection size of 59 accessions was recommended to balance representativeness and diversity. We proposed a reverse power function for the percentage of accessions to be included in a core collection. We started at a high value for small numbers of accessions, and the percentage decreased as the accession number increased. then level off at 10% as the accession number reached 1000 and above. Full article
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13 pages, 10976 KiB  
Article
Phytolith Content Negatively Affects Forage Quality of Eragrostis curvula (Schrad.) Nees
by Jimena Gallardo, Marina Díaz, José Carballo, Antonio Garayalde and Viviana Echenique
Agronomy 2023, 13(3), 924; https://doi.org/10.3390/agronomy13030924 - 21 Mar 2023
Viewed by 1660
Abstract
Phytoliths are intra and extracellular siliceous deposits present in different plant tissues. Si uptake and transport are mediated by Lsi genes and its concentration is associated with forage quality. Our objective was to determine the phytolith content in seven Eragrostis curvula genotypes at [...] Read more.
Phytoliths are intra and extracellular siliceous deposits present in different plant tissues. Si uptake and transport are mediated by Lsi genes and its concentration is associated with forage quality. Our objective was to determine the phytolith content in seven Eragrostis curvula genotypes at the outbreak and re-growth stages to assess its relationship with the forage quality parameters and perform a genome-wide analysis to detect the presence/absence of Lsi genes. The mean values of the phytolith content of dry matter varied between 1.94–2.26% and 2.72–4.71% at the outbreak and re-growth stages, respectively, with highly significant differences among the genotypes and phenological stages. A highly negative correlation was observed in the phytolith content and in vitro dry matter digestibility and crude protein, revealing its importance as a selection parameter in breeding programs. A positive correlation was obtained between the phytolith content and lignin, neutral detergent fiber, and acid detergent fiber. The main morphotypes of the phytoliths included saddle-shaped, bulliform, and acicular cells. Genes Lsi1, Lsi2, Lsi3, and Lsi6, previously reported in silica uptake, were identified and compared with related species, being the gene sequences highly conserved, meaning that its accumulation is probably due to differences in the gene expression or different allelic variants among cultivars. Full article
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13 pages, 5142 KiB  
Article
Karrikin1 Enhances Drought Tolerance in Creeping Bentgrass in Association with Antioxidative Protection and Regulation of Stress-Responsive Gene Expression
by Zhen-Zhen Tan, Yi-Ting Wang, Xia-Xiang Zhang, Heng-Yue Jiang, Ya Li, Li-Li Zhuang, Jing-Jin Yu and Zhi-Min Yang
Agronomy 2023, 13(3), 675; https://doi.org/10.3390/agronomy13030675 - 25 Feb 2023
Cited by 2 | Viewed by 1743
Abstract
Karrikins are active components of smoke that can promote seed germination and regulate seedling morphogenesis. However, the role of karrikins as alleviators of abiotic stress remains largely elusive. In this study, we examined whether exogenous application of karrikin1 (KAR1) might [...] Read more.
Karrikins are active components of smoke that can promote seed germination and regulate seedling morphogenesis. However, the role of karrikins as alleviators of abiotic stress remains largely elusive. In this study, we examined whether exogenous application of karrikin1 (KAR1) might improve drought tolerance in creeping bentgrass (Agrostis stolonifera cv. PennA4), and investigated the underlying mechanism. We found that exogenous application of 100 nM KAR1 enhanced drought tolerance in creeping bentgrass, as manifested by significant increases in leaf relative water content, efficiency of photosystem II, leaf chlorophyll content, proline content, and membrane stability, as well as significantly enhanced activities of antioxidant enzymes. RT–PCR analysis indicated that improved drought stress tolerance by application of KAR1 might be related to upregulation expression of karrikin-responsive genes (KAI2, MAX2 and AFL1), transcription factors (ABF3, bHLH148, MYB13 and DREB2A), antioxidant defense genes (Cu/Zn-SOD, APX2, CAT1, and POD2), and downregulation expression of chlorophyll-degradation genes (PPH and Chl-PRX). These findings suggest that KAR1 may promote the drought tolerance of creeping bentgrass by activating karrikin-responsive genes and transcription factors, enhancing proline accumulation and antioxidant capacity, and suppressing leaf senescence under prolonged drought stress. Full article
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19 pages, 3891 KiB  
Article
Integrative Transcriptome and Chlorophyll Fluorescence Test Analysis Shed New Light on the Leaf Senescence Mechanism of Zoysia japonica
by Jin Guan, Xifeng Fan, Yuesen Yue, Lixin Xu, Ke Teng and Shuxia Yin
Agronomy 2023, 13(3), 623; https://doi.org/10.3390/agronomy13030623 - 22 Feb 2023
Cited by 2 | Viewed by 1303
Abstract
Zoysia japonica is an important warm-season turfgrass used worldwide. The decreased aesthetic quality and functionality during leaf senescence hamper its further utilization. However, information about the transcriptional mechanism and genes involved in leaf senescence in Z. japonica needs to be more extensive. Therefore, [...] Read more.
Zoysia japonica is an important warm-season turfgrass used worldwide. The decreased aesthetic quality and functionality during leaf senescence hamper its further utilization. However, information about the transcriptional mechanism and genes involved in leaf senescence in Z. japonica needs to be more extensive. Therefore, to better understand leaf senescence in Z. japonica, we investigated the integrated analysis of chlorophyll fluorescence test (JIP-test) and RNA sequencing (RNA-seq) of mature and senescent leaves. First, we identified 22,049 genes, of which 4038 were differentially expressed genes (DEGs). The results for gene expression profiles were evaluated using quantitative real-time PCR. A total of 2515 genes have homologous genes in other plants. The matched known-function SAGs are mainly involved in chlorophyll degradation and plant hormone response. A total of 539 differentially expressed transcription factor genes, including AP2/ERF-ERF, NAC, WRKY, bHLH, and MYB, were identified to be associated with leaf senescence. Next, senescence represses chlorophyll biosynthesis while upregulating chlorophyll degradation. Senescence harms the integrity and functionality of PSII, PSI, and the intersystem electron transport chain. In addition, IAA biosynthesis was inhibited, whereas ABA and ET biosynthesis were activated in leaf senescence, and senescence activates signal transduction of IAA, ABA, and ET. These findings add to our understanding of the regulatory mechanism of leaf senescence. The senescence-associated genes are candidate targets for providing new insight into leaf senescence modeling in Z. japonica. They provided a theoretical foundation to reveal the functions of senescence-associated genes and chlorophyll catabolic genes involved in leaf senescence. Full article
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12 pages, 3307 KiB  
Article
Foliar Application of Carnosine and Chitosan Improving Drought Tolerance in Bermudagrass
by Tian Hao, Zhimin Yang, Jianfeng Liang, Jingjin Yu and Jun Liu
Agronomy 2023, 13(2), 442; https://doi.org/10.3390/agronomy13020442 - 1 Feb 2023
Cited by 5 | Viewed by 1460
Abstract
Drought stress is one of the crucial factors affecting plant growth and development in turfgrass species, especially during the summer season. Exogenous plant growth regulators are an effective and convenient approach to mitigating the adverse effects of drought stress on plant growth. The [...] Read more.
Drought stress is one of the crucial factors affecting plant growth and development in turfgrass species, especially during the summer season. Exogenous plant growth regulators are an effective and convenient approach to mitigating the adverse effects of drought stress on plant growth. The objectives of this study were to reveal the effects of exogenous carnosine or chitosan on turf performance and physiological indexes in bermudagrass (Cynodon transvaalensis × C. dactylon) in response to drought stress. Bermudagrass was foliar sprayed with carnosine or chitosan, and dose-dependent effects on turf quality were observed under drought stress. Under drought stress, foliar application of either carnosine (0.03%) or chitosan (10 mg L−1) significantly increased turf quality, chlorophyll content, leaf relative water content, and decreased electrolyte leakage, malonaldehyde, and hydrogen peroxide content in comparison with untreated control in bermudagrass. Moreover, exogenous carnosine treatment significantly enhanced the activities of both catalase and peroxidase, but chitosan application only increased catalase activity. The results of this experiment were beneficial to the development of new plant growth regulators and would provide helpful insights for turf management under drought-stressed conditions. Full article
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13 pages, 2493 KiB  
Article
Accumulation of Alkaloids in Different Tall Fescue KY31 Clones Harboring the Common Toxic Epichloë coenophiala Endophyte under Field Conditions
by Randy D. Dinkins, Brenda L. Coe, Timothy D. Phillips and Huihua Ji
Agronomy 2023, 13(2), 356; https://doi.org/10.3390/agronomy13020356 - 26 Jan 2023
Viewed by 1333
Abstract
Tall fescue (Lolium arundinaceum) is a highly adaptable forage, pasture and turf grass that is grown on over 14 M ha in the eastern half of the United States and in other temperate regions of the world. A significant factor in [...] Read more.
Tall fescue (Lolium arundinaceum) is a highly adaptable forage, pasture and turf grass that is grown on over 14 M ha in the eastern half of the United States and in other temperate regions of the world. A significant factor in adaptability, productivity and stand persistence is in part due to the presence of an intercellular, seed-transmissible, endophytic fungus, Epichloë coenophiala. Epichloë endophytes have been shown to produce a number of alkaloid compounds only in planta, some that are beneficial in repelling insects, while others are toxic to animals. The goal of this work was to monitor the level of the ergot and loline (classified as pyrrolizidine) alkaloid accumulation in individual plants to determine the plant genotype contribution to alkaloid concentrations. The experimental design consisted of sixteen tall fescue KY31 clones in a space-planted, replicated trial over three years. Our results demonstrated that while changes in the alkaloid concentrations for each plant/endophyte genotype were observed over the three years, the overall alkaloid levels remained relatively constant when compared to other plant/endophyte genotypes combinations in the field. Additionally, overall levels of the ergot and loline alkaloid accumulation did not vary in the same way over the three years. Since the E. coenophiala endophyte genotype was the same across all clones, our results indicate that it is the plant genotype that is responsible for determining alkaloid levels in each plant, and suggest that the signal(s) from the plant to the endophyte may not be the same for ergot and loline alkaloid production. Full article
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13 pages, 2062 KiB  
Article
Effect of Harvest Time on the Seed Yield and Quality of Kengyilia melanthera
by Yao Ling, Shuai Yuan, Yanli Xiong, Shuming Chen, Junjie Feng, Junming Zhao, Chenglin Zhang, Xiong Lei, Minghong You, Shiqie Bai and Xiao Ma
Agronomy 2023, 13(1), 55; https://doi.org/10.3390/agronomy13010055 - 23 Dec 2022
Viewed by 1500
Abstract
Kengyilia melanthera is one of the most important forages, and has received significant attention as a desirable ecological pioneer grass for conserving grasslands and mitigating degradation pressure in a region. It is widely distributed in the alpine sandy meadow zone of the Eastern [...] Read more.
Kengyilia melanthera is one of the most important forages, and has received significant attention as a desirable ecological pioneer grass for conserving grasslands and mitigating degradation pressure in a region. It is widely distributed in the alpine sandy meadow zone of the Eastern Qinghai–Tibet Plateau (QTP). Therefore, determining the optimal harvest time of this species is critical. A two-year field experiment (2016–2017) was utilized in this study to evaluate the impact of eight harvest times on the seed yield and quality of K. melanthera ‘Aba’. The results show that the fresh weight (FW), dry weight (DW), seed yield (SY), thousand-grain weight (TGW), accelerated aging germination percentage (AAGP), and dehydrogenase activity (DA) of seeds increased with the extension of harvest time in two trial years, while the water content (WC) of seeds decreased. In both trial years, the germination percentage (GEP), germination potential (GP), and acid phosphatase activity (APA) of seeds increased initially and then decreased with the extension of harvest time. The comprehensive evaluation of the membership function and hierarchical clustering revealed that the 30th day after peak anthesis was the optimal harvest time for both 2016 and 2017. During this time, FW, DW, SY, TGW, AAGP, DA, WC, GEP, GP, and APA reached their optimal value, with 0.815 g, 0.518 g, 1773.67 kg·hm−2, 143.81%, 66%, 16.23 µg·mL−1, 36.01%, 87%, 85%, and 2.50 nmol·min−1 in 2016 and 0.805 g, 0.515 g, 1847.42 kg·hm−2, 133.96%, 65%, 16.52 µg·mL−1, 36.04%, 86.5%, 83.5%, and 2.55 nmol·min−1 in 2017, respectively. This study uncovers several high-efficiency and long-term technological solutions for cultivating high yields and quality production of K. melanthera in East QTP. Full article
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15 pages, 1321 KiB  
Article
Effect of Sodium Chloride Salt on Germination, Growth, and Elemental Composition of Alfalfa Cultivars with Different Tolerances to Salinity
by Surendra Bhattarai, Seth Lundell and Bill Biligetu
Agronomy 2022, 12(10), 2516; https://doi.org/10.3390/agronomy12102516 - 15 Oct 2022
Cited by 4 | Viewed by 1955
Abstract
The aim of this study was to evaluate physiological responses and elemental composition of three salt tolerant alfalfa (Medicagosativa L.) cultivars, ‘Halo’, ‘Bridgeview’, ‘Rugged’, and two intolerant cultivars ‘Rangelander’ and ‘Vernal’ under five salinity levels (0 dSm−1, 4 dSm [...] Read more.
The aim of this study was to evaluate physiological responses and elemental composition of three salt tolerant alfalfa (Medicagosativa L.) cultivars, ‘Halo’, ‘Bridgeview’, ‘Rugged’, and two intolerant cultivars ‘Rangelander’ and ‘Vernal’ under five salinity levels (0 dSm−1, 4 dSm−1, 8 dSm−1, 12 dSm−1 and 16 dSm−1) in a sand based hydroponic system in the greenhouse. The germination percentage among the cultivars was highest for ‘Halo’ under salt stress. ‘Rugged’ and ‘Halo’ had higher seed vigor than the other cultivars in 16 dSm−1 EC. Among the alfalfa cultivars, ‘Rugged’ had the highest chlorophyll content at 0–12 dSm−1 EC. There was variation for root (p = 0.01) and shoot (p = 0.03) biomass among the alfalfa cultivars. Salt stress reduced (p < 0.001) plant height and shoot biomass, with 4.2% and 7.9% reduction for each 1 dS m−1 increase, respectively. Shoot biomass showed a positive correlation with plant height (p < 0.001, r = 0.80), chlorophyll content (p < 0.001, r = 0.56), root biomass (p < 0.001, r = 0.51), but was not correlated with seed vigor. This study demonstrated that seed vigor in the germination stage can not be used to predict salt tolerance of alfalfa at mature growth stages, however plant height and leaf chlorophyll content can serve as physiological markers for high shoot biomass selection at mature growth stages under salt stress. Full article
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15 pages, 9083 KiB  
Article
Callus Irradiation Is an Effective Tool for Creating New Seashore Paspalum Germplasm for Stress Tolerance
by Zhuyi Bai, Qing Yu, Yuying Zheng, Zhiyong Wang, Yu Liu, Jun Liu, Zhimin Yang and Yu Chen
Agronomy 2022, 12(10), 2408; https://doi.org/10.3390/agronomy12102408 - 5 Oct 2022
Viewed by 1562
Abstract
Seashore paspalum (Paspalum vaginatum Swartz) is a perennial warm-season turfgrass which is known for its superb salinity tolerance. Compared to bermudagrass, seashore paspalum exhibited the adverse character of faster vertical growth, wider leaf, weak cold-, drought- and disease-resistance. In this study, we [...] Read more.
Seashore paspalum (Paspalum vaginatum Swartz) is a perennial warm-season turfgrass which is known for its superb salinity tolerance. Compared to bermudagrass, seashore paspalum exhibited the adverse character of faster vertical growth, wider leaf, weak cold-, drought- and disease-resistance. In this study, we aimed to improve these unfavorable traits of seashore paspalum through the strategy of callus irradiation. The results showed that 2108 regenerated plants were obtained following the method of the seashore paspalum calluses irradiated by 60Co-γ rays (dose: 60 Gy, dose rate: 1 Gy/min). Morphological traits were measured combining with cluster analysis on the regenerated plants to select mutant lines with short leaves (A24 and A82) and thin leaves (A24, A83, and A120) as well as dwarfism (B73, B28, B3, A29, and B74). In addition, we found various mutant characters such as greenish leaf sheath (A69 and A71), soft leaf (B77, B17, and B110), and strong erectness (B5 and B9) under continuous observation. Through the comprehensive tolerance analysis following the index of survive rate, relative water content, leaf electrolyte leakage, MDA content; photochemical efficiency and leaf wilting coefficient, three drought-tolerant lines (A55, B72, and B44) and one cold-tolerant line (B59) were screened. This research proved that callus irradiation is an effective way to create new seashore paspalum germplasm, which provides valuable materials for accelerating the breeding process of seashore paspalum and further excavating the molecular regulatory mechanisms of these traits in turfgrass. Full article
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15 pages, 2429 KiB  
Article
Metabolomics and Hormone Level Analysis of Seashore paspalum Dwarf Mutant T51
by Yong Zhang, Jun Liu, Jingjin Yu and Zhimin Yang
Agronomy 2022, 12(10), 2254; https://doi.org/10.3390/agronomy12102254 - 21 Sep 2022
Viewed by 1201
Abstract
The use of slow-growing Seashore paspalum dwarf varieties is an effective way to reduce mowing frequency. Here, the differences in metabolism and hormone levels between Seashore paspalum dwarf mutant T51 and WT were investigated. Finally, the genes associated with the dwarf phenotype were [...] Read more.
The use of slow-growing Seashore paspalum dwarf varieties is an effective way to reduce mowing frequency. Here, the differences in metabolism and hormone levels between Seashore paspalum dwarf mutant T51 and WT were investigated. Finally, the genes associated with the dwarf phenotype were screened in combination with our previous studies. At the metabolic level, 236 differential metabolites were identified. Further screening of hormone-related differential metabolites found that ABA and SA of T51 were increased significantly, while IAA and its intermediate metabolite indolepyruvate of T51 were decreased significantly. Endogenous hormone content assay showed that there was no difference in GA and BR content between T51 and WT; However, the IAA content of T51 was significantly reduced compared with WT. The results of exogenous hormone treatment showed that the sensitivity of T51 to exogenous hormones was IAA > GA > BR. TAA1, YUCCA, and NIT were down-regulated at both the transcriptional and protein levels; CYP79B2 and CYP79B3 were down-regulated at the protein level but had no difference at the transcriptional level. In conclusion, we propose that the down-regulated expression of TAA1, YUCCA, NIT, CYP79B2, and CYP79B3 leads to the decrease of IAA content, which is one of the important reasons for the dwarf phenotype of T51; TAA1, YUCCA, and NIT are important candidate genes related to T51 dwarf. Full article
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16 pages, 3033 KiB  
Article
Exogenous Salicylic Acid Optimizes Photosynthesis, Antioxidant Metabolism, and Gene Expression in Perennial Ryegrass Subjected to Salt Stress
by Ziyue Wang, Shuang Dong, Ke Teng, Zhihui Chang and Xunzhong Zhang
Agronomy 2022, 12(8), 1920; https://doi.org/10.3390/agronomy12081920 - 15 Aug 2022
Cited by 9 | Viewed by 1767
Abstract
Salicylic acid (SA) is a plant growth regulator that can enhance the abiotic stress tolerance of plants; however, the physiological mechanisms are not yet fully understood. The objective of this study was to examine whether exogenous SA could enhance the salt tolerance of [...] Read more.
Salicylic acid (SA) is a plant growth regulator that can enhance the abiotic stress tolerance of plants; however, the physiological mechanisms are not yet fully understood. The objective of this study was to examine whether exogenous SA could enhance the salt tolerance of perennial ryegrass (Loliumperenne L.; PRG) and investigate the physiological underlying mechanisms. SA was applied to the foliage of PRG at five concentrations (0, 0.25, 0.5, and 1 mM). The SA-treated grass was grown under either control (0 mM NaCl) or salt stress (250 mM NaCl) conditions for 24 d. The SA treatments reduced the leaf electrolyte leakage (EL), malonaldehyde (MDA), and hydrogen peroxide (H2O2) content by 36%, 41%, and 40%, respectively, relative to the control under salt stress as measured at 24 d. The SA treatments also alleviated the decline in the leaf photosynthetic rate (Pn), stomatal conductance (gs), nitrate activity (NR), turfgrass quality (TQ) ratings, and chlorophyll (Chl) content under salt stress. In addition, exogenous SA increased the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), and peroxidase (POD) as well as the expression levels of the Cyt Cu/ZnSOD, FeSOD, APX, CAT, and POD genes under salt stress. The results of this study suggested that the foliar application of SA at 0.25 and 0.5 mM may enhance photosynthesis and antioxidant defense systems and thus improve tolerance to salt stress in perennial ryegrass. Full article
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14 pages, 2254 KiB  
Article
Development of SSR Markers Based on Transcriptome Sequencing and Verification of Their Conservation across Species of Ornamental Pennisetum Rich. (Poaceae)
by Yidi Guo, Lingyun Liu, Yuesen Yue, Xifeng Fan, Wenjun Teng, Hui Zhang, Kang Gao, Jin Guan, Zhihui Chang and Ke Teng
Agronomy 2022, 12(7), 1683; https://doi.org/10.3390/agronomy12071683 - 15 Jul 2022
Cited by 4 | Viewed by 1562
Abstract
Pennisetum species have importance in foraging, agriculture, energy-production, the environment, and landscaping. To promote the preservation and utilization of ornamental Pennisetum resources, we developed simple sequence repeat (SSR) markers from the Pennisetum setaceum cv. ‘Rubrum’ transcriptome and verified their conservation in 38 sources. [...] Read more.
Pennisetum species have importance in foraging, agriculture, energy-production, the environment, and landscaping. To promote the preservation and utilization of ornamental Pennisetum resources, we developed simple sequence repeat (SSR) markers from the Pennisetum setaceum cv. ‘Rubrum’ transcriptome and verified their conservation in 38 sources. Our transcriptome sequencing efforts generated 58.91 Gb of clean data containing 55,627 unigenes. We functionally annotated 30,930 unigenes, with functions enriched in translation and ribosomal structure and biogenesis. Database comparisons indicated that the closest relative of P. setaceum cv. ‘Rubrum’ is Setaria italica. Over five thousand SSR markers were detected in the transcriptomic data. We selected 38 pairs of highly polymorphic SSR markers from 50 randomly selected SSR markers. Based on genetic diversity analysis of 38 ornamental Pennisetum sources, we obtained 312 polymorphic bands, with an average of 8.21 alleles per primer. Principal coordinate analyses and generation of a, which proved that Pennisetum has moderate genetic diversity. In addition, fingerprint maps were constructed to improve Pennisetum identification. The transcriptome data generated by our study enhances the transcriptional information available for P. setaceum. This study lays the foundation for the collection and utilization of ornamental Pennisetum resources and provides a basis for future breeding projects using this species. Full article
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14 pages, 2282 KiB  
Article
Exogenous Application of GABA Alleviates Alkali Damage in Alfalfa by Increasing the Activities of Antioxidant Enzymes
by Donghuan Li, Depeng Zhang, Zizhao Zhang, Yimei Xing, Na Sun, Shuo Wang and Hua Cai
Agronomy 2022, 12(7), 1577; https://doi.org/10.3390/agronomy12071577 - 29 Jun 2022
Cited by 4 | Viewed by 1602
Abstract
Alfalfa (Medicago sativa L.) is a widely grown and important forage crop. However, alkali stress is detrimental to alfalfa yield and nutritional quality. Gamma-aminobutyric acid (GABA) is a signaling molecule, it participates in and responds to metabolic regulation related to plant growth [...] Read more.
Alfalfa (Medicago sativa L.) is a widely grown and important forage crop. However, alkali stress is detrimental to alfalfa yield and nutritional quality. Gamma-aminobutyric acid (GABA) is a signaling molecule, it participates in and responds to metabolic regulation related to plant growth and development and stress. In this study, we clarify the effect of spraying alfalfa seedlings with GABA on the alkali tolerance of the seedlings. We determined that exogenous application of GABA at 75 mmol/L improved the resistance of alfalfa seedlings to alkali stress caused by exposure to 100 mmol/L NaHCO3, pH 8.5. Exogenous GABA significantly increased the chlorophyll content, the accumulation of soluble sugars in the plants, significantly decreased their relative electrical conductivity, malondialdehyde (MDA), superoxide anion (O2) and hydrogen peroxide (H2O2) contents, and significantly increased the activities of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD). Exogenous GABA increased the activities of GAD and GABA-T, increased the content of glutamate and endogenous GABA, and regulated the expression of the genes MsGAD, MsGABA-T and MsGDH. In alfalfa plants that survived for a long time, compared to the control group, root length and fresh weight were significantly higher. Exogenous GABA had a positive effect on the resistance of alfalfa seedlings to alkali stress, and the effect was closely associated with GAD and GABA-T activity, glutamate content and the levels of endogenous GABA and antioxidants. This work provides a new method for the cultivation of early-stage alfalfa seedlings under low or moderate alkali stress conditions through the application of 75 mmol/L GABA. Full article
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14 pages, 2148 KiB  
Article
Overexpression of a Thioredoxin-Protein-Encoding Gene, MsTRX, from Medicago sativa Enhances Salt Tolerance to Transgenic Tobacco
by Xinhang Duan, Zhaoyu Wang, Yu Zhang, Han Li, Mei Yang, Hang Yin, Jing Cui, Hua Chai, Yonghang Gao, Guofu Hu and Pan Zhang
Agronomy 2022, 12(6), 1467; https://doi.org/10.3390/agronomy12061467 - 18 Jun 2022
Cited by 9 | Viewed by 2064
Abstract
Thioredoxin (TRX) is a small molecule protein that participates in the redox process and plays a decisive role in various functions of plants. However, the role of TRX in Medicago sativa (alfalfa), a widely cultivated perennial herb of legume, is still poorly understood. [...] Read more.
Thioredoxin (TRX) is a small molecule protein that participates in the redox process and plays a decisive role in various functions of plants. However, the role of TRX in Medicago sativa (alfalfa), a widely cultivated perennial herb of legume, is still poorly understood. Here, we isolated MsTRX from alfalfa and determined the characteristics in improving salt tolerance by assaying the phenotype and physiological changes and the expression of stress-response genes in transgenic tobacco. The expression of MsTRX was similar in alfalfa roots, leaves, and inflorescences, and was downregulated in response to cold, drought, and salt treatment. The overexpression of MsTRX in tobacco promoted the accumulation of soluble sugar (SS) and proline; enhanced the activity of peroxidase (POD); and induced the upregulation of beta-amylase 1 (BAM1), lipid-transfer protein 1 (LTP1), candidate signal molecules/sensor relay proteins (CBSX3), superoxide dismutase [Cu-Zn] (Cu/Zn-SOD), superoxide dismutase [Mn] (Mn-SOD), protein gamma response 1 (GR1), dehydrin DHN1-like (ERD10B), and serine/threonine-protein kinase (SnRK2), as well as the downregulation of phyB activation-tagged suppressor1 (BAS1) and serine/threonine-protein kinase that phosphorylates LHCII protein 7 (STN7) under salt stress. These results indicated that MsTRX improves salt tolerance via maintaining osmotic homeostasis, scavenging reactive oxygen species (ROS), and regulating the transcription of stress-response genes in plants. In our study, we provided a new understanding of how MsTRX improves salt stress in plants and how MsTRX can be included in future breeding programs to improve salt tolerance in alfalfa. Full article
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16 pages, 2814 KiB  
Article
Growth and Morphological Responses of Kentucky Bluegrass to Homogeneous and Heterogeneous Soil Water Availabilities
by Wei Liu, Fuchun Xie, Yajun Chen and Guowen Cui
Agronomy 2022, 12(6), 1265; https://doi.org/10.3390/agronomy12061265 - 25 May 2022
Cited by 1 | Viewed by 1631
Abstract
Understanding the effect of water heterogeneity on the growth and water integration of clonal plants is important for scientific water management. In controlled field plots, we conducted a study by creating three different soil water treatments comprising four patches with different soil water [...] Read more.
Understanding the effect of water heterogeneity on the growth and water integration of clonal plants is important for scientific water management. In controlled field plots, we conducted a study by creating three different soil water treatments comprising four patches with different soil water supplies using Kentucky bluegrass (Poa pratensis L.) as the materials. The objective was to explore the differences in the growth indices and morphological attributes, and the possible water integration in ‘Arcadia’ Kentucky bluegrass in plots and patches with different soil water availabilities. Soil water deficit resulted in the declined biomass, root/shoot ratio and leaf relative water content of the whole genet, decreased leaf length and height of mother ramet, reduced leaf width and height of daughter ramets, and significant changes in the structures of vascular bundles in rhizomes and leaves. However, the leaf length, leaf width, height and leaf relative water content of daughter ramets in heterogeneous water-poor patches were recovered to the levels in water-rich patches. In addition, the diameter of the vessel in the xylem and percentage of the xylem area in leaf vascular bundles of daughter ramets in the heterogeneous water-poor patch were insignificantly different from those in water-rich patches. These results demonstrated that water integration among interconnected ramets promoted the growth status of daughter ramets in heterogeneous water-poor patches. However, the water translocation in interconnected ramets subjecting to heterogeneous water supplies was not investigated using stable isotope labelling in this study. Thus, the directions and patterns of water translocation among ramets necessitate further research. Full article
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16 pages, 2309 KiB  
Article
Morphophysiological Responses of Two Cool-Season Turfgrasses with Different Shade Tolerances
by Lili Dong, Liangbing Xiong, Xiaoyang Sun, Saud Shah, Zhixin Guo, Xueying Zhao, Lizhi Liu, Lintao Cheng, Zhi Tian, Fuchun Xie and Yajun Chen
Agronomy 2022, 12(4), 959; https://doi.org/10.3390/agronomy12040959 - 15 Apr 2022
Cited by 3 | Viewed by 1948
Abstract
Understanding the differences in cool-season turfgrass responses to shade is critical for future turfgrass management and breeding for improved shade tolerance. The purpose of this study was to evaluate the shade-tolerance mechanisms of two cool-season turfgrass species in terms of turf performance, growth, [...] Read more.
Understanding the differences in cool-season turfgrass responses to shade is critical for future turfgrass management and breeding for improved shade tolerance. The purpose of this study was to evaluate the shade-tolerance mechanisms of two cool-season turfgrass species in terms of turf performance, growth, and physiological characteristics. Two turfgrass species, namely, ’SupraNova’ (Poa. supina Schrad.) and ‘Lark’ (Lolium perenne L.), were subjected to 0 (CK, unshaded), 35% (LS), 70% (MS), and 92% (HS) shade, respectively. Compared with ‘Lark’, ‘SupraNova’ showed better turf quality (TQ) and turf color intensity (TCI) under shade. The total length and surface area of the roots of ‘Lark’ gradually decreased as the shade increased, while those of ‘SupraNova’ increased and then decreased with increasing shade. The chlorophyll fluorescence photochemical quenching coefficient (qP), electron transport rate (ETR), and maximum quantum yield of primary photosystem II (PSII) photochemistry (Fv/Fm) decreased significantly under HS; however, these decreases were more significant in ‘Lark’ than in ‘SupraNova’. The leaf reflectance of the two turfgrasses under shade was lower than that under CK, but the leaf reflectance of ‘Lark’ was higher than that of ‘SupraNova’ in the visible light band. The normalized difference vegetation index (NDVI) of the two grasses first decreased and then increased. The NDVI of ‘Lark’ under shade was slightly higher than that under CK. ‘SupraNova’ showed strong tolerance on the basis of malondialdehyde (MDA), hydrogen peroxide (H2O2), superoxide anion (O2·), and ascorbic acid (AsA) contents and superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activity. The MDA, H2O2, O2·, and AsA contents and SOD, POD, and CAT activity (which represent indicators) changed the most under MS. Taken together, the results indicated that the adaptability of ‘SupraNova’ to shade was better than that of ‘Lark’. Full article
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12 pages, 2585 KiB  
Article
An Optimized Tobacco Hairy Root Induction System for Functional Analysis of Nicotine Biosynthesis-Related Genes
by Shangqian Qin, Yanrong Liu, Jianping Yan, Shiwen Lin, Wanjun Zhang and Bingwu Wang
Agronomy 2022, 12(2), 348; https://doi.org/10.3390/agronomy12020348 - 29 Jan 2022
Cited by 5 | Viewed by 3486
Abstract
Rhizobium rhizogenes-mediated plant hairy root induction is a convenient method for functional study of root-specific genes. To develop an optimized tobacco hairy root induction system and study gene function in nicotine biosynthesis, we investigated hairy root induction by three R. rhizogenes strains, [...] Read more.
Rhizobium rhizogenes-mediated plant hairy root induction is a convenient method for functional study of root-specific genes. To develop an optimized tobacco hairy root induction system and study gene function in nicotine biosynthesis, we investigated hairy root induction by three R. rhizogenes strains, R1601, K599, and LBA9402, on different media with leaf discs from plants of different ages, and we observed that the strain LBA9402 used for explant infection exhibited the highest hairy root induction rate with 4 and 8 week old leaf discs of the tobacco ‘Coker176’ on 2/3MS medium, and it could also be used as a cargo delivering foreign genes to hairy roots. Overexpression of MsSPL12 gene, an alfalfa (Medicago sativa) SQUAMOSA promoter binding protein-like (SPL) transcription factor, significantly improved nicotine production in transgenic hairy roots, reaching 1.38–1.85 mg/g compared to 0.5 mg/g of the controls. Expression analysis of the nicotine biosynthesis and transport-related genes responding to methyl-jasmonate (MeJA) treatment revealed a significant upregulation of NtMPO2 responsible for increased nicotine biosynthesis in MsSPL12 transgenic hairy roots. Our results establish a high-throughput approach for gene functional characterization in the hairy roots of a tobacco elite cultivar, ‘Coker176’, as well as suggest a system for efficiently manipulating tobacco nicotine biosynthesis. Full article
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