华中农业大学柑橘抗逆团队解析非生物逆境下多胺积累的分子调控机制

　　Arginine decarboxylase （ADC�?mediated putrescine （Put� biosynthesis plays an im portant role in plant abiotic stress response. SnRK2 （SNF1-related protein kinases 2� and ABF （ABA-respo nse element binding factors� are core compo nents of ABA signaling pathway involved in drought stress response. We previously reported that ADC of Po ncirus trifoliata （PtrADC� functions in drought tolerance. However, whether and how SnRK2 and ABF regulate PtrADC to modulate putrescine accumulation under drought stress remains largely unclear.

　　Herein, we employed a set of physiological, biochemical, and molecular approaches to reveal that a protein complex composed of PtrSnRK2.4 and PtrABF2 modulates putrescine biosynthesis and drought tolerance by directly regulating PtrADC.

　　PtrABF2 was up-regulated by dehydration in an ABA-dependent manner. PtrABF2 activated PtrADC by directly binding to its promoter and positively regulated drought tolerance via modulating putrescine accumulation. PtrSnRK2.4 interacts with and phosphorylates PtrABF2 at Ser93. PtrSnRK2.4-mediated PtrABF2 phosphorylation is essential for its trans criptio nal regulation of PtrADC. Besides, PtrSnRK2.4 was shown to play a positive role in drought tolerance and putrescine synthesis.

　　Taken together, this study sheds new light on the regulatory module SnRK2.4-ABF2-ADC respo nsible for fine-tuning putrescine accumulation under drought stress, which advances our understanding on trans criptio nal regulation of putrescine synthesis and plant drought resistance mechanism.

　　论文链接� https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.18526