Abstract：
The combined stress studies provide fundamental knowledge that could assist in producing multiple stress resilient crops. The fungal phytopathogen, Macrophomina phaseolina is a major limiting factor in the productivity of the crop, Vigna radiata (mungbean). This fungal species tends to flourish under hot and dry conditions. Therefore, in this study the salicylic acid (SA) mediated stress responses in contrasting mungbean cultivars (Shikha and RMG-975) exposed to combined M. phaseolina infection (F) and drought stress (D) have been elucidated. The combined stress was applied to ten days seedlings in three orders i.e. drought followed by fungal infection (DF), drought followed by fungal infection with extended water deficit (DFD) and fungal infection followed by drought stress (FD). The severity of infection was analyzed using ImageJ analysis. Besides, the concentration of SA has been correlated with the phenylpropanoid pathway products, expression of pathogenesis-related proteins (β-1,3-glucanase and chitinase) and the specific activity of certain related enzymes (phenylalanine ammonia lyase, lipoxygenase and glutathione-S-transferase). The data revealed that the cultivar RMG-975 was relatively more tolerant than Shikha under individual stresses. However, the former became more susceptible to the infection under DFD treatment while the latter showed tolerance. Otherwise, the crown rot severity was reduced in both the cultivars under other combined treatments. The stress response analysis suggested that enhanced chitinase expression is vital for tolerance against both, the pathogen and drought stress. Also, it was noted that plants treat each stress combination differently and the role of SA was more prominently visible under individual stress conditions.
摘要：
综合胁迫研究提供了可以帮助生产多种抗逆性作物的基本知识。真菌植物病原体，Macrophominaphaseolina是作物生产力的主要限制因素，Vignaradiata（绿豆）。这种真菌物种倾向于在炎热和干燥的条件下蓬勃发展。因此,在这项研究中，阐明了水杨酸（SA）介导的与绿豆品种（Shikha和RMG-975）相比的应激反应。组合胁迫以三个顺序应用于十天幼苗，即干旱，然后真菌感染（DF），干旱，其次是真菌感染，长期缺水（DFD）和真菌感染，其次是干旱胁迫（FD）。使用ImageJ分析分析感染的严重程度。此外,SA的浓度与苯丙素途径产物相关，发病相关蛋白（β-1,3-葡聚糖酶和几丁质酶）的表达和某些相关酶（苯丙氨酸氨裂解酶，脂氧合酶和谷胱甘肽-S-转移酶）。数据显示，在单个胁迫下，品种RMG-975的耐受性比Shikha高。然而,在DFD治疗下，前者变得更容易感染，而后者表现出耐受性。否则,在其他组合处理下，两个品种的冠腐严重程度均降低。应激反应分析表明，增强的几丁质酶表达对于对两者的耐受性至关重要，病原体和干旱胁迫。此外，注意到植物对每种胁迫组合的处理方式不同,并且SA的作用在个体胁迫条件下更显著可见。
