Title: A novel kinase subverts Aluminum resistance by boosting Ornithine decarboxylase-dependent putrescine biosynthesis

Xiang Pei Liu, Li Jun Gao, Ben Tao She, Gui Xin Li, Yun Rong Wu, Ji Ming Xu, Zhong Jie Ding, Prof, Jian Feng Ma, Shao Jian Zheng

Abstract

Rice, as one of the most aluminum (Al) resistant cereal crops has developed more complicated Al resistance mechanisms than others. By using forward genetic screening from a rice EMS mutant library, we obtained a mutant showing specifically high sensitivity to Al. Through MutMap analysis followed by a complementation test, we identified the causal gene, Al related Protein Kinase (ArPK) for Al-sensitivity. ArPK expression was induced by a relatively longer exposure to high Al concentration in the roots. The result of RNA-seq indicated the functional disorder in arginine metabolism pathway with down-regulation of N-acetylornithine deacetylase (NAOD) expression and up-regulation of Ornithine decarboxylase1 (ODC1) expression in arpk mutant. Al specifically and rapidly up-regulated ODC1 expression and causes overaccumulation of putrescine (Put), while the ODC inhibitor DFMO (difluoromethylornithine) reverted Al-sensitive phenotype of arpk, suggesting that over accumulation of endogenous Put might be harmful for root growth, and that ArPK seems to act as an endogenous inhibitor of ODC1 action to maintain suitable endogenous Put level under Al treatment. Overall, we identified ArPK and its putative repressive role in controlling a novel ODC-dependent Put biosynthesis pathway specifically affecting rice Al resistance, thus enriching the fundamental understanding of plant Al resistance.

Link:  https://onlinelibrary.wiley.com/doi/10.1111/pce.14371