Comprehensive evaluation of agronomic traits, physiological responses, and gene expression in chickpea cultivars under fungal stress

Chickpea (Cicer arietinum L.), a widely grown legume with significant economic importance, serves as an important nutrient source for humans. However, its production is severely constrained by Fusarium wilt, caused by the pathogen Fusarium oxysporum. Due to the high pathogenic variability, effective control remains challenging, and the plant's defense responses are not yet fully understood. In this study, we provide novel insights by identifying cultivar-specific responses and uncovering novel gene expression profiles associated with Fusarium resistance, which advance current understanding beyond previous studies. An integrative approach combining agronomic, physiological, and molecular analyses was used to evaluate chickpea cultivars under fungal stress. We assessed the disease severity index (DSI) to quantify infection levels and evaluated various morphological traits, including plant height, root length, number of pods per plant, days to maturity, 100-seed weight, and shoot biomass, to determine the physical impact of fungal stress. Antioxidant enzyme activities, including superoxide dismutase (SOD), peroxidase (POD), and polyphenol oxidase (PPO), were significantly elevated, reflecting an enhanced antioxidative response to mitigate reactive oxygen species generated during pathogen attack. Biochemical parameters such as malondialdehyde (MDA), protein, and chlorophyll content were also measured, with increased MDA levels indicating increased lipid peroxidation under stress. Additionally, strong positive correlations among SOD, POD, PPO, and MDA highlight a coordinated antioxidant response that helps minimize oxidative damage. Similarly, the protein and chlorophyll contents exhibited significant correlations with enzyme activities, suggesting their roles in enhancing stress resilience. Moreover, real-time quantitative PCR analysis revealed changes in gene expression related to defense pathways, with significant upregulation of WRKY55 and MADS-Box transcription factor 23-like genes under fungal stress. This molecular response aligns with the physiological data, depicting the role of both antioxidant enzymes and gene expression in chickpea's defense mechanisms. This integrative analysis of agronomic traits, antioxidant responses, and gene expression under fungal stress conditions provides valuable insights for enhancing chickpea resilience against Fusarium wilt. Despite these findings, further research is needed to explore additional genetic factors contributing to resistance and to validate these biomarkers across diverse chickpea germplasms. Future studies should focus on applying these insights to breeding programs to develop Fusarium-resistant cultivars suitable for various agro-climatic conditions.