Agronomy

2025

Jump to: 2024, 2023, 2022, 2021

19 pages, 2931 KiB

Open AccessArticle

A Dirigent Gene, ZmDIR11, Positively Regulates Drought Tolerance in Maize

by Zhixiong Zhao, Yuan Guan, Tao Qin, Hongjian Zheng, Hui Wang, Wen Xu, Wei Gu, Diansi Yu, Jihui Wei and Yinxiong Hu

Agronomy 2025, 15(3), 604; https://doi.org/10.3390/agronomy15030604 - 28 Feb 2025

Viewed by 509

Abstract

The DIR gene family, which encodes Dirigent proteins, plays a crucial role in plant development and stress responses. However, the functions and mechanisms of this family in maize remained underexplored. This study identified ZmDIR11, a member of the maize Dirigent protein family, [...] Read more.

The DIR gene family, which encodes Dirigent proteins, plays a crucial role in plant development and stress responses. However, the functions and mechanisms of this family in maize remained underexplored. This study identified ZmDIR11, a member of the maize Dirigent protein family, and explored its role in drought tolerance. ZmDIR11 shared conserved regions with homologous proteins in wheat, rice, and Arabidopsis. RT-qPCR analysis revealed that ZmDIR11 expression is upregulated in leaves under drought and PEG stress, while subcellular localization confirmed its presence in the endoplasmic reticulum. Virus-induced gene silencing (VIGS) and EMS mutagenesis demonstrated that ZmDIR11 silencing or mutation significantly reduces drought tolerance in maize seedlings, indicating its positive regulatory role. Silencing or mutation of ZmDIR11 led to decreased growth parameters (plant height, root length, fresh weight, dry weight, and chlorophyll content) under drought stress, alongside a reduced antioxidant capacity, as evidenced by increased levels of MDA and ROS and decreased activities of SOD, CAT, and POD. Furthermore, ZmDIR11 mutation impaired the synthesis of ABA and zeatin, downregulating key genes in the ABA (ZmABA1, ZmNCED3, ZmSnRK2.6) and zeatin (ZmIPT4, ZmCKO5, ZmCKO4b) pathways. Drought-responsive genes (ZmRD20, ZmRD22, ZmDREB2A) and lignan biosynthesis genes (Zm4CL, ZmC3H, ZmCAD1) are also downregulated in ZmDIR11 mutants. In conclusion, ZmDIR11 enhances drought tolerance in maize by regulating antioxidant capacity, ABA and zeatin synthesis, and lignan metabolism. This study provides new insights into the role of DIR genes in drought tolerance and offers a potential genetic resource for breeding drought-resistant maize varieties. Full article

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16 pages, 6834 KiB

Open AccessArticle

Development of Genome-Wide Unique Indel Markers for a Heat-Sensitive Genotype in Wheat (Triticum aestivum L.)

by Huijie Zhai, Kunpeng Xu, Meng Wang, Zhenchuang Wang, Ziyang Cai, Ao Li, Anxin He, Xiaoming Xie, Lingling Chai, Mingjiu Liu, Xingqi Ou and Zhongfu Ni

Agronomy 2025, 15(1), 169; https://doi.org/10.3390/agronomy15010169 - 11 Jan 2025

Cited by 1 | Viewed by 1108

Abstract

A chromosome segment substituted line (CSSL) represents an ideal resource for studying quantitative traits like thermotolerance. To develop wheat inter-varietal CSSLs with E6015-3S (a heat-sensitive genotype) being the recipient parent, genome-wide unique DNA markers are urgently needed for marker-assisted selection. In this study, [...] Read more.

A chromosome segment substituted line (CSSL) represents an ideal resource for studying quantitative traits like thermotolerance. To develop wheat inter-varietal CSSLs with E6015-3S (a heat-sensitive genotype) being the recipient parent, genome-wide unique DNA markers are urgently needed for marker-assisted selection. In this study, 11,016 primer pairs targeting 5036 indel sites were successfully designed for E6015-3S, with an average density of 0.36 indels per Mbp. These primer pairs are believed to be unique and polymorphic in the wheat genome; as gathered from the evidence, (i) 76.18 to 99.34% of the 11,016 primer pairs yielded a single hit during sequence alignment with 18 sequenced genomes, (ii) 83.59 to 90.98% of 1042 synthesized primer pairs amplified a single band in 16 wheat accessions, and (iii) 59.69 to 99.81% of the tested 1042 primer pairs were polymorphic between E6015-3S and 15 individual wheat accessions. These primer pairs are also anticipated with excellent resolvability on agarose or polyacrylamide gels, since most of them have indel sizes from 15 to 46 bp, amplicon sizes from 141 to 250 bp, and polymorphism ratios from 6.0 to 25.0%. Collectively, these primer pairs are ideal DNA markers for inter-varietal CSSL development and more broad applications, like germplasm classification, seed purity testing, genetic linkage mapping, and marker-assisted breeding in wheat, owing to their uniqueness, polymorphism, and easy-to-use characteristics. Full article

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2024

Jump to: 2025, 2023, 2022, 2021

14 pages, 1870 KiB

Open AccessArticle

Evaluation of Cold Resistance at Seedling Stage for 70 Peanut Genotypes Based on Photosynthetic Fluorescence Characteristics

by Linmei Ye, Tao Wang, Renye Wu, Conghui Zheng, Liuqi Zhan, Jianhong Chen, Shengyao Guo and Yongkuai Chen

Agronomy 2024, 14(8), 1699; https://doi.org/10.3390/agronomy14081699 - 1 Aug 2024

Cited by 4 | Viewed by 1123

Abstract

Low-temperature stress is one of the factors affecting the growth and development of peanuts. Currently, biochemical detection technologies for crop freeze damage are well established. In the context of rapid development in optical sensing technology and smart agriculture, non-destructive crop freeze damage detection [...] Read more.

Low-temperature stress is one of the factors affecting the growth and development of peanuts. Currently, biochemical detection technologies for crop freeze damage are well established. In the context of rapid development in optical sensing technology and smart agriculture, non-destructive crop freeze damage detection based on such technologies has gained increasing attention. The accurate detection, early warning, and targeted control of crop cold damage are particularly important. In this study, 70 peanut germplasm resources were collected and used for the research objectives. Indoor low-temperature seedling identification was conducted at 25 °C (the control group) and 5 °C (low-temperature stress group) for 7 days. Photosynthetic fluorescence values in leaves, as well as 13 indicators (Fo, Fm, Fv, Fv/Fm, Fv’/Fm’, ΦPSII, NPQ, qP, Rfd, Pn, Gs, Ci, and Tr), were analyzed for their responses to low-temperature stress. The results showed that under low-temperature stress, the Pn and Ci of peanut seedlings exhibited an ascending trend, while Tr and other indicators showed a decreasing trend compared to the control group. Based on the relative coefficients of resistance to low temperature for each individual indicator, a comprehensive non-destructive evaluation of cold resistance was conducted using methods such as principal component analysis, cluster analysis, and stepwise regression. Through principal component analysis, the 13 individual physiological indicators were transformed into 3 comprehensive indicators. The 70 peanut varieties were divided into 4 categories based on their resistance to low temperature: sensitive materials, moderately sensitive materials, moderately cold-tolerant materials, and cold-tolerant materials. Additionally, a mathematical model for evaluating cold resistance in peanuts was established. Full article

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17 pages, 5155 KiB

Open AccessArticle

Transcriptomic Analysis of Maize Inbred Lines with Different Leaf Shapes Reveals Candidate Genes and Pathways Involved in Density Tolerance

by Shulei Guo, Yiyang Guo, Jun Zhang, Yinghui Song, Jinsheng Guo, Liangming Wei, Qianjin Zhang, Zhenhua Wang, Zanping Han, Liru Cao, Xin Zhang and Xiaomin Lu

Agronomy 2024, 14(7), 1506; https://doi.org/10.3390/agronomy14071506 - 11 Jul 2024

Viewed by 1133

Abstract

Maize is an important food and feed crop. Under limited arable land area, the cultivation of high-density-tolerance crops is a key factor in promoting yield improvement. Leaf width and stalk strength are important influences on density tolerance in maize. However, no comprehensive transcriptomic [...] Read more.

Maize is an important food and feed crop. Under limited arable land area, the cultivation of high-density-tolerance crops is a key factor in promoting yield improvement. Leaf width and stalk strength are important influences on density tolerance in maize. However, no comprehensive transcriptomic analysis has focused on maize’s leaf width and stalk strength formation mechanisms. In this study, comparative transcriptomic analyses demonstrated that significant transcriptome changes occurred regarding leaf width and stalk strength of narrow-leaved and wide-leaved maize inbred lines, with a total of 5001 differentially expressed genes (DEGs) identified. Enrichment analysis showed that phenylpropanoid biosynthesis, starch and sucrose metabolism, phytohormone signaling, amino acid metabolism, and brassinosteroid biosynthesis were significantly correlated with the formation of maize leaf shape and stalk strength and that the genes in these pathways were primarily involved in cell wall formation. Weighted gene co-expression network analysis identified 2 modules significantly correlated with leaf width and stalk strength, from which 11 hub genes were further identified. The 11 leaf and stem development genes in different pathways were validated using qRT-PCR. These findings can provide a theoretical basis for the mechanism of narrow-leaf and high-strength stalk formation in high-density-tolerance maize and contribute to the proposal of a breeding strategy for yield improvement. Full article

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2023

Jump to: 2025, 2024, 2022, 2021

19 pages, 12331 KiB

Open AccessArticle

Identification, Characterization, and Expression Profiling of Maize GATA Gene Family in Response to Abiotic and Biotic Stresses

by Yuchao Hu, Jingyi Huang, Li Yu, Changjin Wang, Xinwei Zhang, Xinxin Cheng, Haibing Yu and Kaijing Zhang

Agronomy 2023, 13(7), 1921; https://doi.org/10.3390/agronomy13071921 - 20 Jul 2023

Cited by 7 | Viewed by 2611

Abstract

GATA transcription factor is crucial for plant growth and development, physiological metabolism, and environmental response, which has been reported in many plants. Although the identification of maize GATA genes has been reported previously, the number of maize GATA genes was incomplete, and the [...] Read more.

GATA transcription factor is crucial for plant growth and development, physiological metabolism, and environmental response, which has been reported in many plants. Although the identification of maize GATA genes has been reported previously, the number of maize GATA genes was incomplete, and the expression patterns of maize GATA genes were not analyzed. Therefore, in this study, the GATA gene family of maize (Zea mays L.) was systematically analyzed. Forty-one GATA family genes were identified in the maize and were divided into four groups. The gene structure of each subgroup was basically consistent with that of the motif. The maize GATA genes were distributed on 10 chromosomes, including 3 and 17 pairs of tandem and segmental duplication genes, respectively. Fourteen types of cis-acting elements were identified in the promoter sequences of maize GATA family genes, involving four categories: light response, stress, hormone, and growth and development. The tissue-specific expression analysis of maize GATA family genes revealed that 4 GATA genes were highly expressed in almost all the maize tissues, and 11 GATA genes were not expressed in almost all tissues. The other maize GATA family genes showed a tissue-specific expression pattern. The results of RNA-seq reanalysis of publicly available transcriptome sequencing big data revealed that the gene ZmGATA37 was significantly down-regulated in response to abiotic stresses including high temperature, low temperature, drought, waterlogging, and salt, and significantly up-regulated in response to biotic stresses including smut disease, Maize Iranian mosaic virus infection, beet armyworm and aphid infestations. This indicated that the ZmGATA37 gene plays an important role in maize growth and development. Our findings offer new insight into the potential role of GATA transcription factors in abiotic and biotic stresses and provide a theoretical groundwork for the molecular mechanisms underlying maize adaptation to such stress. Full article

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2022

Jump to: 2025, 2024, 2023, 2021

17 pages, 2073 KiB

Open AccessArticle

Winter Cereal Reactions to Common Root Rot and Crown Rot Pathogens in the Field

by Ahmed Saad, Bethany Macdonald, Anke Martin, Noel L. Knight and Cassandra Percy

Agronomy 2022, 12(10), 2571; https://doi.org/10.3390/agronomy12102571 - 19 Oct 2022

Cited by 5 | Viewed by 2728

Abstract

In Australia, Fusarium pseudograminearum and F. culmorum are the two main fungi causing crown rot, while Bipolaris sorokiniana is the causal agent of common root rot. Fusarium graminearum is typically linked with Fusarium head blight; however, it has been associated with crown rot [...] Read more.

In Australia, Fusarium pseudograminearum and F. culmorum are the two main fungi causing crown rot, while Bipolaris sorokiniana is the causal agent of common root rot. Fusarium graminearum is typically linked with Fusarium head blight; however, it has been associated with crown rot in Australia and other parts of the world. This study investigated the reactions of single cultivars of barley, bread wheat, durum wheat, oat, and triticale to inoculation with strains of F. pseudograminearum, F. culmorum, F. graminearum and B. sorokiniana in field trials across two seasons. Fusarium pseudograminearum and F. culmorum caused greater visual discolouration than F. graminearum and B. sorokiniana on both stems and sub crown internodes of all hosts. Fusarum pseudograminearum caused the greatest reduction in plant dry weight across hosts in both years. Durum wheat (cv. Hyperno) barley (cv. Grimmett), bread wheat (cv. Livingston) and triticale (cv. Endeavour) observed significantly high levels of visual discolouration on stems when inoculated with F. pseudograminearum, while oat (cv. Genie) exhibited the least visual discolouration. Despite variation in the visual discolouration, the DNA of all pathogens were detected in all cultivars. This research further highlights the complicated nature of the pathogen × strain × cultivar × environment interaction, which remains a challenge in breeding for genetic resistance. The specific infection of each fungus and the host responses in these field trials improves our understanding of disease development and its importance in cropping systems. Full article

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18 pages, 3054 KiB

Open AccessEditor’s ChoiceArticle

Understanding the Role of Physiological and Agronomical Traits during Drought Recovery as a Determinant of Differential Drought Stress Tolerance in Barley

by Md. Hasanuzzaman, Lana Shabala, Timothy J. Brodribb, Meixue Zhou and Sergey Shabala

Agronomy 2022, 12(9), 2136; https://doi.org/10.3390/agronomy12092136 - 8 Sep 2022

Cited by 8 | Viewed by 2744

Abstract

The fast and efficient recovery could be an important trait defining the efficacy of plant drought adaptation. In this work, we aimed to develop a set of simple and appropriate physiological proxies that could be used as reliable indicators to predict plant drought [...] Read more.

The fast and efficient recovery could be an important trait defining the efficacy of plant drought adaptation. In this work, we aimed to develop a set of simple and appropriate physiological proxies that could be used as reliable indicators to predict plant drought responses and validate the role of specific physiological traits such as root length, stomata density, and residual transpiration, in the drought tolerance and recovery in barley. Eighty barley (Hordeum vulgare L.) genotypes were subjected to progressive droughting until the soil moisture level reached 10%, followed by rewatering. Plants were visually scored at the end of drought period and two weeks after rewatering. SPAD values and chlorophyll fluorescence F_v/F_m ratio were also measured, alongside with stomatal density (SD) and residual transpiration (RT). The same genotypes were germinated in paper rolls treated with 15% (w/v) of polyethylene glycol (PEG) 8000 by quantification of changes in the root growth patterns. Responses to drought stress varied among the genotypes, and drought tolerance and recovery scores were significantly correlated with each other. Changes in SPAD value, F_v/F_m ratio and root length were significantly correlated with the drought tolerance and recovery indices. Both indices correlated strongly with the SD and RT of irrigated plants, although in an unexpected direction. We have also correlated the extent of plants’ drought tolerance to their ability to grow in saline soils (a condition often termed a “physiological drought”) and found a positive association between these two traits. The fact that drought tolerant genotype also possessed higher salinity tolerance implies some common mechanisms conferring both traits. Plants having less SD and more RT under irrigated conditions showed higher drought tolerance. It is concluded that lower SD and higher RT under optimal conditions may be used as proxies for drought tolerance in barley. Full article

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14 pages, 648 KiB

Open AccessReview

Cadmium Accumulation in Cereal Crops and Tobacco: A Review

by Shineng Mei, Kaina Lin, Darron V. Williams, Yang Liu, Huaxin Dai and Fangbin Cao

Agronomy 2022, 12(8), 1952; https://doi.org/10.3390/agronomy12081952 - 18 Aug 2022

Cited by 24 | Viewed by 3883

Abstract

Cadmium (Cd) is a toxic heavy metal with no known biological function in plants and one of the most toxic substances released into the environment. Crops, such as rice, maize, wheat and tobacco are the major sources of Cd for humans. Cd toxicity [...] Read more.

Cadmium (Cd) is a toxic heavy metal with no known biological function in plants and one of the most toxic substances released into the environment. Crops, such as rice, maize, wheat and tobacco are the major sources of Cd for humans. Cd toxicity inhibits crop growth and development by affecting many central physiological and biochemical processes, and finally it affects human health via the food chain. To adapt to Cd toxicity, crops have evolved a series of detoxification mechanisms. Immediate responses include rapid changes at the transcriptional level with simultaneous changes at the physiological and metabolic levels. However, the long-term responses involve genetic modifications and epigenetic changes. During the last decade, many genes involved in Cd uptake and translocation have been identified, and many of them are transporters. To decrease the accumulation of Cd in cereal grains and tobacco leaves, a number of approaches have been proposed, including physical and chemical methods, developing and planting low accumulation genotypes using transgenic strategies or marker–trait association breeding. In this review, we describe the toxicity of Cd to crops and human body, advances in the molecular mechanisms of Cd accumulation in cereal crops and tobacco, and approaches to decrease Cd accumulation. Full article

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12 pages, 1123 KiB

Open AccessArticle

Single-Nucleotide Polymorphisms in Bmy1 Intron III Alleles Conferring the Genotypic Variations in β-Amylase Activity under Drought Stress between Tibetan Wild and Cultivated Barley

by Xiaojian Wu, Wenhao Yue, Kangfeng Cai, Huan Wang, Fanrong Zeng and Junmei Wang

Agronomy 2022, 12(8), 1737; https://doi.org/10.3390/agronomy12081737 - 22 Jul 2022

Cited by 3 | Viewed by 1637

Abstract

β-amylase activity is related to the polymorphisms of Bmy1 intron III; however, no attention has been given to such relationships under environmental stresses such as drought. In this study, 73 cultivated barley genotypes and 52 Tibetan wild barley accessions were used to test [...] Read more.

β-amylase activity is related to the polymorphisms of Bmy1 intron III; however, no attention has been given to such relationships under environmental stresses such as drought. In this study, 73 cultivated barley genotypes and 52 Tibetan wild barley accessions were used to test the association between Bmy1 gene intron III polymorphisms and β-amylase activity under drought stress. Our results showed that three alleles, Bmy1.a, Bmy1.b, and Bmy1.c, existed in the examined barley genotypes. Tibetan wild barley had a higher proportion of Bmy1.b, whereas cultivated barley showed a higher proportion of Bmy1.a. Impressively, barley genotypes with Bmy1.b showed a significant increase in β-amylase activity under drought stress, compared with those with Bmy1.a or Bmy1.c, indicating that the Bmy1.b allele might provide more chances for developing barley cultivars with higher β-amylase activity under water stress than both the Bmy1.a and Bmy1.c alleles. Furthermore, the Tibetan wild barley XZ147, belonging to the Bmy1.b allele type, showed significantly higher β-amylase activity than Triumph under drought stress. This might be the result of the unique amino acid substitution M527 or the amino acid composition of R115, D165, A233, S347, and M527 of XZ147. Full article

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18 pages, 1044 KiB

Open AccessReview

Understanding R Gene Evolution in Brassica

by Fangning Zhang, Ting Xiang Neik, Tingting Wu, David Edwards and Jacqueline Batley

Agronomy 2022, 12(7), 1591; https://doi.org/10.3390/agronomy12071591 - 30 Jun 2022

Viewed by 3489

Abstract

Brassica crop diseases caused by various pathogens, including viruses, bacteria, fungi and oomycetes, have devastating effects on the plants, leading to significant yield loss. This effect is worsened by the impact of climate change and the pressure to increase cultivation worldwide to feed [...] Read more.

Brassica crop diseases caused by various pathogens, including viruses, bacteria, fungi and oomycetes, have devastating effects on the plants, leading to significant yield loss. This effect is worsened by the impact of climate change and the pressure to increase cultivation worldwide to feed the burgeoning population. As such, managing Brassica diseases has become a challenge demanding a rapid solution. In this review, we provide a detailed introduction of the plant immune system, discuss the evolutionary pattern of both dominant and recessive disease resistance (R) genes in Brassica and discuss the role of epigenetics in R gene evolution. Reviewing the current findings of how R genes evolve in Brassica spp. provides further insight for the development of creative ideas for crop improvement in relation to breeding sustainable, high quality, disease-resistant Brassica crops. Full article

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14 pages, 1917 KiB

Open AccessArticle

Investigation of Two QTL Conferring Seedling Resistance to Fusarium Crown Rot in Barley on Reducing Grain Yield Loss under Field Environments

by Zhi Zheng, Jonathan Powell, Shang Gao, Cassandra Percy, Alison Kelly, Bethany Macdonald, Meixue Zhou, Philip Davies and Chunji Liu

Agronomy 2022, 12(6), 1282; https://doi.org/10.3390/agronomy12061282 - 27 May 2022

Cited by 2 | Viewed by 2495

Abstract

Fusarium crown rot (FCR) is one of the most damaging cereal diseases in semi-arid regions worldwide. Genetic studies on FCR resistance have mainly focused on disease symptoms measured by the browning of either leaf sheaths in seedlings or stems of mature plants. Two [...] Read more.

Fusarium crown rot (FCR) is one of the most damaging cereal diseases in semi-arid regions worldwide. Genetic studies on FCR resistance have mainly focused on disease symptoms measured by the browning of either leaf sheaths in seedlings or stems of mature plants. Two major QTLs conferring FCR resistance in barley, Qcsr.cpi-1H and Qcrs.cpi-4H, were previously identified in the growth room. They could explain up to 33.4 and 45.3% of phenotypic variance, respectively. This is the first study where the possible effects of FCR-resistant loci identified in the previous studies based on seedling assay are tested for their abilities to reduce grain yield loss. Near isogenic lines (NILs) and backcross (BC) lines targeting these two loci were assessed in the 2017 and 2018 crop seasons. Results from the NILs showed that the presence of a resistance allele at either the 1HL or 4HL locus reduced grain yield loss by an average of 12.0% and 10.7%, respectively. Grain yields of the top BC lines containing resistance alleles at both loci were 34.4% higher than the average of the commercial varieties under FCR inoculation. These lines will be highly valuable in breeding barley varieties with enhanced resistance to FCR. Full article

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30 pages, 1513 KiB

Open AccessReview

Genetic Improvement of Heat Stress Tolerance in Cereal Crops

by Camilla Beate Hill and Chengdao Li

Agronomy 2022, 12(5), 1205; https://doi.org/10.3390/agronomy12051205 - 17 May 2022

Cited by 19 | Viewed by 6143

Abstract

Crop heat stress is a threat to food supply, with heatwaves expected to increase in frequency and intensity globally. In addition to yield loss, heat stress dramatically reduces fertility and seed-setting rate, grain quality and weight, and seed germination and growth. Genetic variability [...] Read more.

Crop heat stress is a threat to food supply, with heatwaves expected to increase in frequency and intensity globally. In addition to yield loss, heat stress dramatically reduces fertility and seed-setting rate, grain quality and weight, and seed germination and growth. Genetic variability for heat stress tolerance can be used in breeding programs to develop tolerant genotypes. The availability of genome assemblies with high-confidence sequences for many cereal crops, including rice, maize, wheat and barley, now allows the identification of heat stress tolerance-associated genes and gene networks. This review focuses on synthesizing current advances in understanding the detrimental effects of heat stress on cereal crop production at the physiological and genetic levels. It provides an account of available genomic resources, genetic variation, candidate genes, and molecular markers for heat stress tolerance. Lastly, this review offers insight into crop genetic improvement for heat stress tolerance, including germplasm screening in glasshouse and field trials, marker-assisted selection, mapping genomic loci and identification of candidate genes, and genomic-assisted breeding. Full article

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15 pages, 3858 KiB

Open AccessArticle

Ectopic Expression of Kenaf (Hibiscus cannabinus L.) HcWRKY50 Improves Plants’ Tolerance to Drought Stress and Regulates ABA Signaling in Arabidopsis

by Xiaoping Niu, Meixia Chen, Zeyuan She, Mohammad Aslam, Jianmin Qi and Yuan Qin

Agronomy 2022, 12(5), 1176; https://doi.org/10.3390/agronomy12051176 - 13 May 2022

Cited by 8 | Viewed by 5341

Abstract

Kenaf (Hibiscus cannabinus L.) is an environmentally friendly, multipurpose fiber crop suitable for osmotic stress tolerance studies. However, the mechanisms of tolerance remain largely unknown. Here, we identified a stress-responsive HcWRKY50 gene from kenaf (Hibiscus cannabinus L.) and studied its function [...] Read more.

Kenaf (Hibiscus cannabinus L.) is an environmentally friendly, multipurpose fiber crop suitable for osmotic stress tolerance studies. However, the mechanisms of tolerance remain largely unknown. Here, we identified a stress-responsive HcWRKY50 gene from kenaf (Hibiscus cannabinus L.) and studied its function and tolerance under drought stress. HcWRKY50 is a nuclear-localized protein. The overexpression of HcWRKY50 in Arabidopsis showed higher drought tolerance, exhibiting increased root length and lateral root number, and reduced stomatal density compared with the control lines. The seed germination and seedling growth of HcWRKY50 transgenic plants showed less sensitivity to ABA but they became more sensitive to ABA in their stomatal aperture. Furthermore, qRT-PCR analysis revealed that HcWRKY50 regulated ABA signaling by promoting the expression of several key ABA-responsive and stress-responsive genes such as RD29B and COR47 in transgenic lines. Taken together, this study demonstrated that the kenaf transcription factor HcWRKY50 regulates seed germination and seedling growth and improves drought stress tolerance via an ABA signaling pathway. Full article

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11 pages, 1654 KiB

Open AccessArticle

Topping Inhibited Potassium Uptake via Regulating Potassium Flux and Channel Gene Expression in Tobacco

by Taibo Liang, Huaxin Dai, Waleed Amjad Khan, Yadi Guo, Xiangyu Meng, Guiyao Wang and Yanling Zhang

Agronomy 2022, 12(5), 1166; https://doi.org/10.3390/agronomy12051166 - 11 May 2022

Cited by 1 | Viewed by 2301

Abstract

Potassium (K⁺) is mainly absorbed by plants from the soil and is primarily transported within the plant through the xylem. Topping has been reported to cause efflux and loss of K⁺ in plants; however, its effect on the real-time flow [...] Read more.

Potassium (K⁺) is mainly absorbed by plants from the soil and is primarily transported within the plant through the xylem. Topping has been reported to cause efflux and loss of K⁺ in plants; however, its effect on the real-time flow rate and genotypes with varying K⁺ accumulation ability is still unknown. Therefore, we carried out a pot experiment containing sand culture using two tobacco cultivars EY1 (high K⁺ accumulating) and Y87 (low K⁺ accumulating). The results demonstrated the change of K⁺ flow direction from influx to efflux in the roots of both cultivars due to topping. The percentage ratio of K⁺ efflux to influx was estimated to be 18.8% in EY-1 and 157.0% in Y87, respectively. We noticed a decline in indole acetic acid (IAA) content due to topping, which activated the expression of K⁺ efflux channel gene NTORK1 and inhibited the expression of K⁺ influx channel genes NKT1 and NtKC1. Furthermore, K⁺ loss from the roots increased due to topping, which led to decreased K⁺ concentration in entire tobacco plant. Topping had a more serious impact on the K⁺ efflux rate and K⁺ loss in Y87. IAA application after topping, in turn, decreased the K⁺ loss in both the cultivars. We conclude that topping caused a decrease in IAA concentration and K⁺ losses in tobacco leaves, and these losses can be mitigated by the exogenous application of IAA. Full article

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14 pages, 1530 KiB

Open AccessArticle

Comparative Transcriptional Analysis of Two Contrasting Rice Genotypes in Response to Salt Stress

by Xiaoxue Ye, Weiwei Tie, Jianlong Xu, Zehong Ding and Wei Hu

Agronomy 2022, 12(5), 1163; https://doi.org/10.3390/agronomy12051163 - 11 May 2022

Cited by 4 | Viewed by 2478

Abstract

Improving rice salt-tolerance is an effective way to deal with the increasing food demand caused by soil salinization and population growth. Nevertheless, the molecular mechanisms of rice salt-tolerance remain elusive. In this study, comparative transcriptomic analyses were performed to identify salt-tolerance genes that [...] Read more.

Improving rice salt-tolerance is an effective way to deal with the increasing food demand caused by soil salinization and population growth. Nevertheless, the molecular mechanisms of rice salt-tolerance remain elusive. In this study, comparative transcriptomic analyses were performed to identify salt-tolerance genes that were either specifically regulated or more changed in salt-tolerant cultivar FL478 relative to salt-sensitive cultivar 93-11. In total, 1423, 175, and 224 salt-tolerance genes were identified under 200 mM NaCl treatment for 6 h, 24 h, and 72 h, respectively. These genes were commonly enriched in transport and peroxidase/oxidoreductase activity across all timepoints, but specially enriched in transcription regulator activity at 6 h under salt stress. Further analysis revealed that 53 transporters, 38 transcription factors (TFs), and 23 reactive oxygen species (ROS) scavenging enzymes were involved in salt adaptation of FL478, and that overall, these salt-tolerance genes showed a faster transcriptional expression response in FL478 than in 93-11. Finally, a gene co-expression network was constructed to highlight the regulatory relationships of transporters, TFs, and ROS scavenging genes under salt-stress conditions. This work provides an overview of genome-wide transcriptional analysis of two contrasting rice genotypes in response to salt stress. These findings imply a crucial contribution of quickly transcriptional changes to salt tolerance and provide useful genes for genetic improvement of salt tolerance in rice. Full article

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8 pages, 850 KiB

Open AccessArticle

Tissue-Specific Responses of Cereals to Two Fusarium Diseases and Effects of Plant Height and Drought Stress on Their Susceptibility

by Zhouyang Su, Zhi Zheng, Meixue Zhou, Sergey Shabala and Chunji Liu

Agronomy 2022, 12(5), 1108; https://doi.org/10.3390/agronomy12051108 - 2 May 2022

Cited by 4 | Viewed by 2376

Abstract

Multiple species of Fusarium can infect wheat and barley plants at various stages of development. Fusarium head blight (FHB) refers to the infection of spikes and developing kernels by these pathogens, and crown rot (FCR) infers to infection of the root, crown, and [...] Read more.

Multiple species of Fusarium can infect wheat and barley plants at various stages of development. Fusarium head blight (FHB) refers to the infection of spikes and developing kernels by these pathogens, and crown rot (FCR) infers to infection of the root, crown, and basal stem by Fusarium pathogens. Interestingly, most of the host genes conferring resistance to these two diseases are different in both wheat and barley, and plants’ susceptibility to these two diseases are oppositely affected by both plant height and reduced water availability. Available results do not support the hypothesis that reduced height genes have different effects on biotrophic and necrotrophic diseases. Rather, differences in temperature and humidity in microenvironments surrounding the infected tissues and the difference in the physical barriers originating from the difference in cell density seem to be important factors affecting the development of these two diseases. The fact that genes conferring resistance to Type I and Type II of FHB are different indicates that it could be feasible to identify and exploit genes showing resistance at the three distinct stages of FCR infection for breeding varieties with further enhanced resistance. The strong association between FCR severity and drought stress suggests that it should be possible to exploit some of the genes underlying drought tolerance in improving resistance to FCR. Full article

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15 pages, 12231 KiB

Open AccessReview

Waterlogging Stress Physiology in Barley

by James De Castro, Robert D. Hill, Claudio Stasolla and Ana Badea

Agronomy 2022, 12(4), 780; https://doi.org/10.3390/agronomy12040780 - 24 Mar 2022

Cited by 18 | Viewed by 5611

Abstract

Barley (Hordeum vulgare L.) is the most susceptible cereal species to excess moisture stress. Waterlogging-induced hypoxia causes major morphological, physiological, and metabolic changes, some of which are regulated by the action of plant growth regulators and signal molecules including nitric oxide. Recent [...] Read more.

Barley (Hordeum vulgare L.) is the most susceptible cereal species to excess moisture stress. Waterlogging-induced hypoxia causes major morphological, physiological, and metabolic changes, some of which are regulated by the action of plant growth regulators and signal molecules including nitric oxide. Recent studies have evidenced the participation of phytoglobins in attenuating hypoxic stress during conditions of excessive moisture through their ability to scavenge nitric oxide and influence the synthesis and response of growth regulators. This review will highlight major cellular changes linked to plant responses to waterlogging stress with emphasis on phytoglobins. Full article

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12 pages, 3151 KiB

Open AccessArticle

Aerenchyma Formation in Adventitious Roots of Tall Fescue and Cocksfoot under Waterlogged Conditions

by Nguyen Thi Mui, Meixue Zhou, David Parsons and Rowan William Smith

Agronomy 2021, 11(12), 2487; https://doi.org/10.3390/agronomy11122487 - 8 Dec 2021

Cited by 10 | Viewed by 3984

Abstract

The formation of aerenchyma in adventitious roots is one of the most crucial adaptive traits for waterlogging tolerance in plants. Pasture grasses, like other crops, can be affected by waterlogging, and there is scope to improve tolerance through breeding. In this study, two [...] Read more.

The formation of aerenchyma in adventitious roots is one of the most crucial adaptive traits for waterlogging tolerance in plants. Pasture grasses, like other crops, can be affected by waterlogging, and there is scope to improve tolerance through breeding. In this study, two summer-active cocksfoot (Dactylis glomerata L.) cultivars, Lazuly and Porto, and two summer-active tall fescue (Lolium arundinaceum Schreb., syn. Festuca arundinacea Schreb.) cultivars, Hummer and Quantum II MaxP, were selected to investigate the effects of waterlogging on root growth and morphological change. Cultivars were subjected to four periods of waterlogging treatments (7, 14, 21 and 28 days), while comparable plants were kept under free drained control conditions. The experiment was arranged as a split–split plot design, with waterlogging treatments (waterlogged, control) considered as main plots, time periods (days of waterlogging) as subplots and cultivars as sub-subplots. Plants began to show signs of waterlogging stress 14–21 days after the onset of waterlogging treatments. There were no significant differences in shoot biomass between the waterlogged and control plants of any cultivar. However, waterlogging significantly reduced root dry matter in all cultivars, with greater reduction in cocksfoot (56%) than in tall fescue (38%). Waterlogging also led to increased adventitious root and aerenchyma formation in both species. Cocksfoot cultivars showed a greater increase in adventitious roots, while tall fescue cultivars had a greater proportion of aerenchyma. Both cultivars within each species showed similar responses to waterlogging treatments. However, an extended screening program is needed to identify whether there are varietal differences within species, which could be used to discover genes related to aerenchyma or adventitious root formation (waterlogging tolerance) for use in breeding programs. Full article

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14 pages, 1357 KiB

Open AccessEditor’s ChoiceReview

Improving Crop Lodging Resistance by Adjusting Plant Height and Stem Strength

by Yanan Niu, Tianxiao Chen, Chenchen Zhao and Meixue Zhou

Agronomy 2021, 11(12), 2421; https://doi.org/10.3390/agronomy11122421 - 27 Nov 2021

Cited by 40 | Viewed by 6577

Abstract

Crop height not only determines plant resistance to lodging and crowding, but also affects crop architecture, apical dominance, biomass, and mechanical harvesting. Plant height is determined by the internode elongation, regulated by genes involved in gibberellin (GA) and brassinosteroid (BR) biosynthesis or related [...] Read more.

Crop height not only determines plant resistance to lodging and crowding, but also affects crop architecture, apical dominance, biomass, and mechanical harvesting. Plant height is determined by the internode elongation, regulated by genes involved in gibberellin (GA) and brassinosteroid (BR) biosynthesis or related signaling networks. Plants’ genetic inability to synthesize or respond to GAs and BRs induce dwarfness. However, the signaling mechanisms of GAs and BRs for controlling plant height individually or collectively are still unclear. Since stem mechanically supports plant during the whole life span, components that affect stem physical strength are also important to crop lodging resistance. One of the major components is lignin, which forms stem structure, thus contributing to crop lodging resistance. In this review, we looked into the reported genes involved in lignin, GAs, and BRs biosynthesis and summarized the signaling networks centered by these genes. Then, we filled the knowledge gap by modifying plant height through interrupting normal GA and BR metabolism utilizing core gene inhibitors. Therefore, we highly endorsed the current approaches of using plant growth regulators (PRGs) to maintain an ideal plant height under lodging stress, and proposed possibilities of modifying crop culm strength against lodging as well. Full article

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