Imran Haider Shamsi

Rapeseed (Brassica napus L.) is a globally vital oilseed crop for edible oil, biofuel and animal feed production, yet its yield and quality are severely threatened by a narrow genetic foundation, scarce germplasm and recurrent abiotic stresses including drought and salinity. Mediator subunits have been proven to be critical for abiotic stress tolerance in model plants, but systematic research on the Brassica napus Mediator (BnaMED) gene family and its stress regulatory mechanism in Brassica napus remains largely lacking. In this study, we identified 189 BnaMED members phylogenetically clustered into five subfamilies, with extensive family expansion mainly driven by whole-genome duplications, accompanied by functional differentiation and redundancy to bolster polyploid adaptability. Chromosomal mapping revealed 176 BnaMED genes unevenly distributed across A/C subgenomes. Through gene collinearity analysis among Brassica napus, Arabidopsis thaliana, Glycine max, Oryza sativa, and Zea mays, we found that Brassica napus shares high collinearity with dicotyledonous species, such as Glycine max and Arabidopsis thaliana, indicating evolutionary conservation specific to dicots. Protein physicochemical properties and promoter cis-element analysis uncovered diverse structural features and extensive involvement in light, hormone and stress signaling pathways. Tissue expression profiling demonstrated distinct subfamily specificity and functional divergence. The quantitative real-time PCR (qRT-PCR) analysis revealed that under salt stress, endogenous transcript levels of BnaMED family members BnaA09g34000D, BnaA09g23620D, BnaC03g31860D and BnaA06g10800D were up-regulated, whereas BnaA08g23170D and BnaA08g22420D were transcriptionally repressed. Following drought-stress treatment, all six genes (BnaA09g34000D, BnaA09g23620D, BnaA09g50540D, BnaA06g10800D, BnaA08g23170D and BnaA08g22420D) displayed markedly reduced expression. These observations reflect stress-specific regulatory strategies underlying abiotic-stress adaptation. In addition, several BnaMED genes showed dynamic expression during floral transition in the semi-winter Zhong Shuang 11 (ZS11) cultivar. This study provides a foundational insight into functional roles of BnaMED genes in rapeseed abiotic stress responses.

Drought is an increasingly frequent constraint for flue‐cured tobacco production. Here we reported the root endophyte Serendipita indica enhancing drought tolerance in Nicotiana tabacum L. (cv. Yunyan 87) and identified the underlying mechanisms using integrated physiology and metabolomics. Seedlings were inoculated with a root‐zone drench of S. indica mycelium/chlamydospore suspension (15 mL per plant, repeated after 3 days), and colonization was confirmed microscopically. Drought markedly decreased net photosynthesis, stomatal conductance, transpiration, intercellular CO ₂ , and total chlorophyll, whereas inoculated plants maintained significantly higher gas‐exchange parameters and chlorophyll contents than drought‐only plants. Antioxidant defense was strengthened under S.i + D, with increased SOD, POD and CAT activities. It reduced H ₂ O ₂ and malondialdehyde in both leaves and roots, accompanied by greater proline and soluble sugar accumulation. UPLC–MS metabolomics revealed pronounced reprogramming: drought altered 168 leaf metabolites (71 up/97 down) and 215 root metabolites (111 up/104 down) relative to CTRL, while S.i + D altered 137 leaf metabolites (78 up/59 down) and 227 root metabolites (117 up/110 down); compared with drought‐only plants, S. indica shifted 100 leaf (55 up/45 down) and 81 root metabolites (41 up/40 down). S. indica reduced drought‐associated tropane/pyridine alkaloid signatures while promoting protective polyols and benzenoids. S. indica improves tobacco drought resilience by coordinating photosynthetic preservation with redox buffering, osmotic adjustment and targeted carbon/nitrogen rerouting, identifying flavonoid and arginine‐proline modules as key metabolic nodes for endophyte‐assisted drought tolerance, opening the doors for further research leading towards the way of constructing a sustainable environment of fungi‐plant interactions.

The study of volatile organic compounds (VOCs)-mediated plant growth promotion has long focused on various beneficial microbial species. As an important natural source of functional biomolecules, the biological function and potential value of VOCs released by plant pathogenic fungi in regulating plant growth still lack sufficient research, and further exploration is needed. In this study, a phytopathogenic fungus Alternaria alstroemeriae (strain Z84) was isolated from Vaccinium dunalianum for the first time, and the effects of its VOCs on the growth of Arabidopsis thaliana and Nicotiana benthamiana were systematically investigated. The results showed that after Z84 VOCs treatment, multiple phenotypic traits of the two plants were significantly improved, and the chlorophyll content was also markedly increased. Transcriptome analysis showed that a total of 1401 differentially expressed genes (DEGs) were identified in the treated A. thaliana, of which 629 were up-regulated and 772 were down-regulated. KEGG enrichment analysis showed that these DEGs were mainly enriched in photosynthesis-antenna proteins, plant–pathogen interaction, glutathione metabolism, plant hormone signal transduction, flavonoid biosynthesis and photosynthesis-related pathways. Metabolomics analysis revealed that Z84 VOCs treatment significantly changed the metabolic profile of A. thaliana, with the most significant changes in amino acid metabolism-related pathways. It is noteworthy that the plant hormone spectrum of A. thaliana was significantly changed after treatment, and the contents of salicylic acid (SA), abscisic acid (ABA) and gibberellins (GAs) were significantly up-regulated. These results not only demonstrate the potential of Z84-derived VOCs to facilitate plant growth but also provide an important basis for further dissecting the molecular mechanisms of plant–pathogenic fungi interactions.

The current state of agriculture heavily relies on chemical fertilizers and pesticides, which can negatively impact plant nutritional quality, plant health, and productivity. Additionally, abiotic stresses pose significant challenges to global agricultural productivity, threatening food security and crop sustainability. Therefore, developing and implementing sustainable alternatives to chemical fertilizers and pesticides is crucial to enhance agricultural productivity and resilience. Recent research highlights the potential of microorganisms, such as plant growth‐promoting rhizobacteria (PGPR), mycorrhizal fungi, and endophytes, as sustainable solutions to improve plant resilience under abiotic stress conditions. However, challenges including scalability, ecological impacts, and the need for standardized application methods persist. This review explores novel microbial approaches to improving crop resilience against abiotic stress, focusing on how microorganisms interact with plants to mitigate stress impacts. Key mechanisms include the production of stress‐alleviating compounds, enhanced nutrient uptake, and modulation of plant stress response pathways. We also examine advanced strategies in plant breeding, emphasizing CRISPR/Cas‐mediated genome editing technologies as powerful tools for elucidating plant‐microbe interactions. A thorough understanding of these interactions is essential for effectively applying genome editing to enhance the functional capacities of plants or associated microbes, ultimately improving key agronomic traits. This review provides a comprehensive overview of these innovative microbial approaches and their practical applications in sustainable agriculture, offering insights into future research directions, such as developing novel microbial strains and optimizing field applications.