Drought suppresses plant salicylic acid defence against herbivorous insects by down-regulating the expression of ICS1 via NAC transcription factor

Many herbivorous insects exhibit enhanced performance and population dynamics on drought-stressed host plants due to induced changes in plant physiology. However, the underlying mechanisms of how drought regulates plant defense against herbivorous insects are still largely unknown. In this study, we...

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Main Authors: Chan Zhao, Wen-Hao Han, Yu-Die Xiong, Shun-Xia Ji, Hui Du, Yu-Jie Chi, Na Chen, He Wu, Shu-Sheng Liu, Xiao-Wei Wang
Format: Article
Language:English
Published: Elsevier 2025-06-01
Series:Plant Stress
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Online Access:http://www.sciencedirect.com/science/article/pii/S2667064X25001551
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Summary:Many herbivorous insects exhibit enhanced performance and population dynamics on drought-stressed host plants due to induced changes in plant physiology. However, the underlying mechanisms of how drought regulates plant defense against herbivorous insects are still largely unknown. In this study, we found that the survival rate and fecundity of whiteflies, notorious global pests, were significantly higher on drought-stressed tobacco. Drought stress did not affect jasmonic acid (JA) accumulation, whereas it significantly decreased the salicylic acid (SA) content by suppressing its biosynthesis. We further demonstrated that drought-induced abscisic acid (ABA) inhibited the expression of isochorismate synthase 1 (ICS1), a key enzyme in the synthesis of SA. The accumulation of ABA induced the expression of abscisic acid responsive NAC domain containing protein 19 (ANAC019), which directly bound to the promoter of NtICS1 and negatively regulated its expression. Finally, we revealed that drought and ABA could activate abscisic acid responsive elements-binding factor 2 (ABF2) transcription factor to up-regulate the expression of NtANAC019. Our study illustrates the significance of cross-talk between abiotic stress and plant-herbivore interactions and reveals the mechanisms leading to altered herbivore fitness on drought-stressed plants.
ISSN:2667-064X