Search Results (319)

With the objective of identifying superior Vernicia montana trees grounded in phenotypic and agronomic traits, this study sought to develop and implement a comprehensive evaluation method which would provide a practical foundation for future clonal breeding initiatives. Using the Vernicia montana propagated from seedling forests grown in the Suxian District of Chenzhou City in southern Hunan Province, we conducted pre-selection, primary selection, and re-selection of Vernicia montana forest stands and took the nine trait indices of single-plant fruiting quantity, single-plant fruit yield, disease and pest resistance, fruit ripening consistency, fruit aggregation, fresh fruit single-fruit weight, fresh fruit seed rate, dry seed kernel rate, and seed kernel oil content rate as the optimal evaluation indexes and carried out cluster analysis and a comprehensive evaluation in order to establish a comprehensive evaluation system for superior Vernicia montana trees. The results demonstrated that a three-stage selection process—consisting of pre-selection, primary selection, and re-selection—was conducted using a comprehensive analytical approach. The pre-selection phase relied primarily on sensory evaluation criteria, including fruit count per plant, tree size, tree morphology, and fruit clustering characteristics. Through this rigorous screening process, 60 elite plants were selected. The primary selection was based on phenotypic traits, including single-plant fruit yield, pest and disease resistance, and uniformity of fruit ripening. From this stage, 36 plants were selected. Twenty plants were then selected for re-selection based on key performance indicators, such as fresh fruit weight, fresh fruit seed yield, dry seed kernel yield, and oil content of the seed kernel. Then the re-selected optimal trees were clustered and analyzed into three classes, with 10 plants in class I, 7 plants in class II, and 3 plants in class III. In class I, the top three superior plants exhibited outstanding performance across key traits: their fresh fruit weight per fruit, fresh fruit seed yield, dry seed yield, and seed kernel oil content reached 41.61 g, 42.80%, 62.42%, and 57.72%, respectively. Compared with other groups, these figures showed significant advantages: 1.17, 1.09, 1.12, and 1.02 times the average values of the 20 reselected superior trees; 1.22, 1.19, 1.20, and 1.08 times those of the 36 primary-selected superior trees; and 1.24, 1.25, 1.26, and 1.19 times those of the 60 pre-selected trees. Fruits counts per plant and the number of fruits produced per plant of the best three plants in class I were 885 and 23.38 kg, respectively, which were 1.13 and 1.18 times higher than the average of 20 re-selected superior trees, 1.25 and 1.30 times higher than the average of 36 first-selected superior trees, and 1.51 and 1.58 times higher than the average of 60 pre-selected superior trees. Class I superior trees, especially the top three genotypes, are suitable for use as mother trees for scion collection in grafting. The findings of this study provide a crucial foundation for developing superior clonal varieties of Vernicia montana through selective breeding. Full article

Corn smut, caused by Ustilago maydis, significantly threatens maize production. This study evaluated 199 maize inbred lines at the seedling stage under greenhouse conditions for resistance to U. maydis, identifying 39 highly resistant lines. A genome-wide association study (GWAS) using the mrMLM model detected 19 significant single-nucleotide polymorphism (SNP) loci. Based on a linkage disequilibrium (LD) decay distance of 260 kb, 226 candidate genes were identified. Utilizing the significant loci chr1_244281660 and chr5_220156746, two kompetitive allele-specific PCR (KASP) markers were successfully developed. A PCR-based sequence-specific oligonucleotide probe hybridization technique applied to the 199 experimental lines and 60 validation lines confirmed polymorphism for both markers, with selection efficiencies of 48.12% and 43.33%, respectively. The tested materials were derived from foundational inbred lines of domestic and foreign origin. Analysis of 39 highly resistant lines showed that the advantageous alleles carrying thymine/cytosine (T/C) predominated at frequencies of 94.87% and 53.84%, respectively. The genotype TTCC conferred high resistance, while CCTT was highly susceptible. The resistance exhibited high heritability and significant gene-by-environment interaction. This work systematically dissects the genetic basis of common smut resistance in maize, identifies favorable alleles, and provides a novel KASP marker-based strategy for developing disease-resistant germplasm. Full article

Asia minor bluegrass (Polypogon fugax), a widespread Poaceae weed, exhibits broad tolerance to abiotic stresses. Validated reference genes (RGs) for reliable RT-qPCR normalization in this ecologically and agriculturally significant species remain unidentified. This study identified eight candidate RGs using transcriptome data from seedling tissues. We assessed the expression stability of these eight RGs across various abiotic stresses and developmental stages using Delta Ct, BestKeeper, geNorm, and NormFinder algorithms. A comprehensive stability ranking was generated using RefFinder, with validation performed using the target genes COR413 and P5CS. Results identified EIF4A and TUB as the optimal RG combination for normalizing gene expression during heat stress, cold stress, and growth stages. EIF4A and ACT were most stable under drought stress, EIF4A and 28S under salt stress, and EIF4A and EF-1 under cadmium (Cd) stress. Furthermore, EIF4A and UBQ demonstrated optimal stability under herbicide stress. Additionally, application of validated RGs revealed higher acetyl-CoA carboxylase gene (ACCase) expression in one herbicide-resistant population, suggesting target-site gene overexpression contributes to resistance. This work presents the first systematic evaluation of RGs in P. fugax. The identified stable RGs provide essential tools for future gene expression studies on growth and abiotic stress responses in this species, facilitating deeper insights into the molecular basis of its weediness and adaptability. Full article

Idesia polycarpa is a valuable woody oil plant with potential for horticultural and industrial applications. However, limited information is available regarding its drought tolerance during the seedling stage. In this study, one-year-old seedlings were subjected to five treatments based on soil relative water content (RWC): moderate drought (T1, 40 ± 5%), severe drought (T2, 20 ± 5%), control (CK, 70 ± 5%), and rewatering following moderate (T3) and severe drought stress (T4), with RWC restored to 70 ± 5%. Under drought stress, seedlings exhibited adaptive responses including reduced growth, enhanced antioxidant enzyme activity, osmotic regulation, and changes in endogenous hormone levels. Seedlings showed good tolerance and recovery under moderate drought, but severe drought caused substantial damage and limited post-rewatering recovery. Pearson correlation and principal component analyses revealed that betaine, APX, SA, IAA, ABA, chlorophyll (a + b) content, and crown growth were strongly associated with drought response and could serve as key indicators for drought resistance assessment in I. polycarpa. These findings provide insights into the physiological mechanisms of drought adaptation and support the development of a reliable evaluation system for drought tolerance in this promising species. Full article

Drought stress poses a major constraint on global crop productivity. Although aspartic proteases (APs) are primarily characterized in plant disease resistance, their roles in abiotic stress adaptation remain largely unexplored. Here, we demonstrate that rice (Oryza sativa) OsAP4 critically regulates drought stress tolerance at the seedling stage. Genetic manipulation through overexpression (OsAP4-OE) or CRISPR knockout (OsAP4-KO) resulted in significantly reduced or enhanced stress tolerance compared to wild-type plants, respectively. Through integrated approaches including yeast two-hybrid, bimolecular fluorescence complementation, pull-down, co-immunoprecipitation, and protein degradation assays, we established that OsAP4 physically interacts with and destabilizes OsCATA/OsCATC, two catalase enzymes responsible for reactive oxygen species (ROS) scavenging. Importantly, OsAP4 modulates ROS production under drought stress treatment conditions. Together, these findings reveal a novel OsAP4-OsCATA/OsCATC regulatory module governing rice drought stress responses. Full article

Orobanche cumana Wallr. is a root parasitic plant that causes considerable yield losses of up to 50% in sunflower Helianthus annuus plantations. The holoparasite fulfills its entire demand for water, minerals, and organic nutrients from the host’s vascular system. Agronomic practices alone are not effective in controlling this pest. This study investigated the mechanism of a verified plant growth-promoting strain, Streptomyces rochei D74, on the inhibition of the parasitism of O. cumana in a co-culture experiment. We conducted potted and sterile co-culture experiments using sunflower, O. cumana, and S. rochei D74. Our results suggest that the inoculated bacteria invoked the sunflower systemic resistance (SAR and ISR) by increasing the activity of resistance-related enzymes (SOD, POD, PPO, and PAL), the gene expression of systemic resistance marker genes (PR-1 and NPR1), ethylene synthesis genes (HACS. 1 and ACCO1), and JA synthesis genes (pin2 and lox). The expression levels of ISR marker genes (lox, HACS. 1, ACCO1, and pin2) increased by 1.66–7.91-fold in the seedling stage. Simultaneously, S. rochei D74 formed a protective layer on the sunflower root surface, preventing O. cumana from connecting to the vascular system of the sunflower roots. In addition, S. rochei D74 reduced 5DS synthesis of the strigol precursor substance, resulting in a reduction in O. cumana germination. These results demonstrated that the S. rochei D74 strain improved systemic resistance and decreased seed germination to prevent O. cumana parasitism. Full article

Maize (Zea mays L.) is one of the most important food crops. Salt stress can hinder crop growth and development, but the molecular mechanisms underlying maize’s response to salt tolerance remain unclear. In this study, we conducted comparative transcriptome, metabolome, and physiological analyses of a salt-tolerant maize inbred line (J1285) subjected to different NaCl concentrations during the seedling stage. The results demonstrated that, with increasing salt concentration, seedling growth parameters and antioxidant enzyme activities (SOD, POD, CAT) exhibited initially increases before subsequently decreasing, peaking at 50–150 mmol/L. Transcriptome data analysis revealed that the experimental groups subjected to 50, 100, 150, and 200 mmol/L treatments had 375, 1043, 2504, and 2328 differentially expressed genes (DEGs) compared to the control group, respectively. Additionally, through GO and KEGG analysis, we found that the DEGs were primarily enriched in the MAPK signaling pathway and plant hormone signal transduction, especially the abscisic acid (ABA) signaling pathway, both of which play instrumental roles in orchestrating the maize response to salt-induced stress. Transcription factors involved in the salt stress response, including WRKY, TIFY, bZIP, and bHLH, were identified. Metabolomic data analysis revealed that the experimental groups subjected to 50, 100, 150 and 200 mmol/L treatments had 44, 335, 278, and 550 differentially expressed metabolites (DEMs) compared to the control group, respectively. The DEMs were mainly enriched in metabolic pathways and the biosynthesis of secondary metabolites. Transcriptomics and metabolomics combined analysis were performed on J1285 seedling leaves, and it was found that the co-enrichment pathways included starch and sucrose metabolism, linoleic acid metabolism, α-linolenic acid metabolism, phenylpropanoid biosynthesis pathway, etc. Collectively, these results will aid in identifying resistance genes and elucidating the molecular mechanisms underlying salt tolerance for maize. Full article

The Orchidaceae family is of significant decorative, pharmaceutical, alimentary, and cultural importance worldwide. This family is very vulnerable due to illegal looting, habitat destruction, and climate change. The development of new hybrids helps meet the demand for specimens that possess outstanding appearance, fragrance, and resistance characteristics and may reduce illegal looting. The objective of this research was to investigate the in vitro propagation of the hybrid Rhyncattleanthe Queen Bee JLA 1 (Rth. Queen Bee JLA 1). Shoot induction was performed with germinated seedlings that were 1 cm in length on semi-solid MS medium with different 6-Benzylaminopurine (BAP), 1-Naphthaleneacetic acid (NAA), 3-Indoleacetic acid (IAA), and 3-indolebutyric acid (IBA) concentrations. Micropropagation was conducted using a temporary immersion system (TIS), a liquid continuous immersion system (CIS), and a conventional semi-solid system (SSS). Afterwards, all regenerated seedlings underwent an acclimatization stage. The highest numbers of shoots (7.04) and leaves (14.28) were obtained with the combination of 1.5 mg L⁻¹ BAP and 0.4 mg L⁻¹ NAA, while the addition of 0.4 mg L⁻¹ IBA in combination with 1.5 mg L⁻¹ BAP enhanced the length of stems (2.12 cm) and leaves (1.88 cm). TIS produced the highest number of shoots (15.68), leaves (22.92), stem length (5.94 cm), and number of leaves (3.50) in seedlings analyzed. The combination of growth regulators BAP and NAA together with the temporary immersion system influenced both the development of the vitroplants and their vegetative development after acclimatization of the hybrid Rth. Queen Bee JLA1 orchid. Full article

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), threatens global wheat production. Breeding resistant varieties is a key to disease control. In this study, 198 modern wheat varieties were phenotyped with the prevalent Pst races CYR33 and CYR34 at the seedling stage and with mixed Pst races at the adult-plant stage. Seven stable resistance varieties with infection type (IT) ≤ 2 and disease severity (DS) ≤ 20% were found, including five Chinese accessions (Zhengpinmai8, Zhengmai1860, Zhoumai36, Lantian36, and Chuanmai32), one USA accession (GA081628-13E16), and one Pakistani accession (Pa12). The genotyping applied a 55K wheat single-nucleotide polymorphism (SNP) array. A genome-wide association study (GWAS) identified 14 QTL using a significance threshold of p ≤ 0.001, which distributed on chromosomes 1B (4), 1D (2), 2B (4), 6B, 6D, 7B, and 7D (4 for CYR33, 7 for CYR34, 3 for mixed Pst races), explaining 6.04% to 18.32% of the phenotypic variance. Nine of these QTL were potentially novel, as they did not overlap with the previously reported Yr or QTL loci within a ±5.0 Mb interval (consistent with genome-wide LD decay). The haplotypes and resistance effects were evaluated to identify the favorable haplotype for each QTL. Candidate genes within the QTL regions were inferred based on their transcription levels following the stripe rust inoculation. These resistant varieties, QTL haplotypes, and favorable alleles will aid in wheat breeding for stripe rust resistance. Full article

Drought is a major factor limiting crop growth and yield. Enhancing drought resistance is an important strategy to sustain higher yields, with an emphasis on developing drought-tolerant cultivars. In this study, 19 sorghum varieties from both domestic and international sources were selected as experimental materials. At the seedling stage, 11 above-ground and below-ground phenotypic traits were investigated. Under 25% PEG-6000 concentration, drought tolerance during the seedling stage was assessed using differential analysis, such as correlation analysis, principal component analysis (PCA), membership function analysis, regression analysis, and cluster analysis. The present results demonstrate that the principal component analysis could represent 77.18% of the data from the original 11 indicators. Total root length, stem diameter, and leaf area were identified as the main evaluation indicators for sorghum seedling drought tolerance. In addition, based on principal component scores (F) and drought tolerance metric values (D), the 19 sorghum varieties were classified into three categories through systematic cluster analysis: two varieties were classified as highly drought-tolerant, nine as moderately drought-tolerant, and eight as drought-sensitive. Two varieties, such as Longza 24 and Jinza 12, were identified as drought-tolerant during the seedling stage and can serve as valuable resources for evaluating drought tolerance throughout the full growth period and for breeding improvements. Hence, this study established a drought tolerance evaluation method by integrating above- and below-ground phenotypic traits indicators, providing theoretical support for the identification of drought-tolerant sorghum. Full article

To identify seedling traits closely associated with drought resistance and to screen for drought-tolerant germplasm, 202 cotton varieties (lines) were evaluated under controlled indoor conditions using a nutrient soil cultivation method. Seedling-stage traits measured included plant height, cotyledon node diameter, true leaf number, chlorophyll content, and fresh and dry biomass of both shoots and roots. Drought resistance was assessed using drought resistance coefficients for each trait, followed by descriptive statistics, principal component analysis (PCA), partial correlation analysis, and comprehensive evaluation via the entropy weight method. PCA and partial correlation analysis revealed that plant height, cotyledon node diameter, aboveground fresh weight, and underground fresh weight were strongly associated with drought resistance at the seedling stage. The comprehensive drought resistance index (D-value) classified the 202 cotton lines into four categories: highly drought-resistant, moderately drought-resistant, drought-sensitive, and highly drought-sensitive. Physiological assays indicated that malondialdehyde (MDA) content in drought-resistant lines first increased and then declined with prolonged drought stress, while it continued to increase in sensitive lines. In contrast, proline (Pro) content and superoxide dismutase (SOD) activity increased steadily in drought-resistant lines but showed negligible changes in sensitive lines. These four morphological traits and three physiological indicators represent reliable criteria for evaluating drought resistance in cotton seedlings. Four highly drought-resistant and thirteen moderately drought-resistant lines were identified, providing valuable germplasm for genetic improvement of drought tolerance in cotton. Full article

Wheat (Triticum aestivum L.) is the world’s most indispensable staple crop and a vital source of food for human diet. Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), constitutes a severe threat to wheat production and in severe cases, the crop fails completely. Anmai1350 (AM1350) is moderately resistant to leaf rust and powdery mildew, and highly susceptible to sheath blight and fusarium head blight. We found that the length and area of mycelium in AM1350 cells varied at different time points of Pst infection. To investigate the molecular mechanism of AM1350 resistance to Pst, we performed transcriptome sequencing (RNA-seq). In this study, we analyzed the transcriptomic changes of the seedling leaves of AM1350 at different stages of Pst infection at 0 h post-infection (hpi), 6 hpi, 24 hpi, 48 hpi, 72 hpi, and 120 hpi through RNA-seq. Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) was used to validate RNA-seq data. It was determined that there were differences in the differentially expressed genes (DEGs) of AM1350, and the upregulation and downregulation of the DEGs changed with the time of infection. At different time points, there were varying degrees of enrichment in the response pathways of AM1350, such as the ”MAPK signaling pathway–plant”, the “plant–pathogen interaction” pathway and other pathways. After Pst infected AM1350, the reactive oxygen species (ROS) content gradually increases. The ROS is toxic to Pst, promotes the synthesis of phytoalexins, and inhibits the spread of Pst. As a result, AM1350 shows resistance to Pst race CYR34. The main objective of this study is to provide a better understanding for resistance mechanisms of wheat in response to Pst infections and to avoid production loss. Full article

Drought stress is one of the main factors limiting seed germination and seedling establishment in field crops such as jalapeño peppers (Capsicum annuum L.). Nanopriming, a seed improvement technique using nanoparticle suspensions, has emerged as a sustainable approach to improving water use efficiency during the early stages of development. This study evaluated the effects of zinc oxide (ZnO, 100 mg·L⁻¹), silicon dioxide (SiO₂, 10 mg·L⁻¹), and their combination (ZnO + SiO₂), stabilized with chitosan, on the germination yield and drought tolerance of jalapeño seeds under mannitol-induced water stress (0%, 15%, and 30%). Compared to the hydroprimed control (T1), nanoparticle treatments consistently improved seed yield. Priming with ZnO (T2) increased the germination percentage by up to 25%, priming with SiO₂ (T3) improved the germination rate by 34%, and the combined treatment (T4: ZnO + SiO₂) improved the fresh weight of the seedlings by 40%. Proline accumulation increased 7.5 times, antioxidant capacity (DPPH) increased 6.5 times, and total phenol content increased 4.8 times in the combined treatment. Flavonoid levels also showed notable increases, suggesting enhanced antioxidant defense. These results clearly demonstrate the superior efficacy of nanoparticle pretreatment compared to conventional hydraulic pretreatment, especially under drought conditions. Multivariate analysis further highlighted the synergistic role of ZnO and SiO₂ in improving osmolite accumulation, antioxidant activity, and water use efficiency. Nanopriming with ZnO and SiO₂ offers a promising, economical, and scalable strategy to improve germination, early growth, and drought resistance in jalapeño pepper cultivation under semi-arid conditions. Full article

Spodoptera frugiperda, a major global agricultural pest, poses significant challenges to chemical control methods due to pesticide resistance and environmental concerns, underscoring the need for sustainable management strategies. Attractants based on host plant volatiles offer a promising eco-friendly approach, but their development for S. frugiperda is hindered by limited research on host recognition mechanisms. This study reveals that female S. frugiperda preferentially oviposit on maize at the seedling stage. Using electrophysiological techniques, we identified p-xylene and (+)-camphor from seedling-stage maize volatiles as key compounds eliciting strong responses in female S. frugiperda. Behavioral assays confirmed that these compounds (p-xylene at the concentration of 5%, 10%, and 20% and (+)-camphor at 1%, 5%, and 10%) significantly attract females, establishing them as the key odor cues for host selection. Moreover, these volatiles are more abundant in seedling-stage maize, suggesting that S. frugiperda assesses maize growth stages based on their concentrations. Importantly, larvae reared on seedling-stage maize exhibited higher survival rates than those on later-stage maize, indicating that oviposition site selection directly affects offspring fitness. These findings demonstrate that S. frugiperda uses p-xylene and (+)-camphor to evaluate maize development and select suitable oviposition sites, thereby enhancing larval survival. This study provides a foundation for developing targeted attractants for S. frugiperda and highlights the seedling stage as a critical period for implementing pest control measures, particularly in autumn maize production, given the higher pest population density during this phase. Full article

Drought stress is a crucial factor limiting plant survival and growth, especially during the seedling establishment stage. A deep understanding of different plants’ responses to drought stress and their drought resistance is of great significance for vegetation restoration under drought conditions. This study selected one-year-old seedlings of Winter Jasmine (Jasminum nudiflorum), Oleander (Nerium oleander), Privet (Ligustrum lucidum), and Redleaf Photinia (Photinia × fraseri) as research objects. Through pot experiments, we investigated the physiological and biochemical responses of these shrubs under different levels of drought stress (control, mild, moderate, and severe drought stress, corresponding to 75%, 60%, 45%, and 30% of field maximum water holding capacity) to comprehensively assess their drought resistance capabilities. The research results indicated that as the level of drought stress increased, significant changes (p < 0.05) occurred in the physiological and biochemical indicators of all four plant species. The chlorophyll content (Chla+b) of Winter Jasmine and Redleaf Photinia gradually decreased with the intensification of stress, while the Chla+b of Oleander showed the most significant decline under moderate stress and Privet was most affected under mild stress. The proline (Pro) and soluble sugar (SS) contents of all four plants exhibited an upward trend, suggesting that the plants coped with drought stress by accumulating these osmoregulatory substances. Drought stress led to damage to plant cell membranes, manifested by an increase in malondialdehyde content (MDA), with Winter Jasmine showing the most pronounced increase. The activities of peroxidase (POD) and superoxide dismutase (SOD) in the four plant species responded differently to drought stress: the POD activity of Oleander and Redleaf Photinia increased with the deepening of stress, while that of Winter Jasmine and Privet decreased. A comprehensive evaluation of the drought tolerance of the four plant species was performed using principal component analysis and affiliation function value methods. The drought tolerance of the four shrubs, from strongest to weakest, was as follows: Redleaf Photinia > Oleander > Privet > Winter Jasmine. This finding provides valuable insights for plant selection in ecological slope protection projects, and Redleaf Photinia and Oleander can be promoted for use in vegetation restoration work under drought conditions. Full article