Among the universal changes that occur with age in multicellular organismsis the decline in regenerative capacity. In mammalian, for example, the heart quickly loses its capacity to regenerate within a brief period after birth. In plants, the root regeneration is triggered by wound-induced auxin biosynthesis. As plants age, the root regenerative capacity is gradually decreased. How wound leads to the auxin burst and how age and woundsignals collaboratively regulate root regenerative capacity arepoorly understood.

　　The research group led by Dr. Jia-Wei Wang now uncover an important role of microRNA156 (miR156), the master regulator of juvenility, in root regenerative capacityin the model plant Arabidopsis thaliana. They find that the increased level of three closely-related miR156-targeted SPL transcription factors, SPL2, SPL10 and SPL11, with age suppresses root regeneration by inhibiting wound-induced auxin biosynthesis. Mechanistically, theydemonstrate that a subset of AP2/ERF transcription factors including ABR1 and ERF109 is rapidly induced by wound and serves as a proxy for woundsignal to induce auxin biosynthesis. In older plants, SPL2/10/11 directly binds to the promotersof AP2/ERFs and attenuates their induction, thereby dampening auxin accumulation at the wound. Overall, these results identify AP2/ERFs as a hub for integration of age and wound signal for root regeneration and may pave the way for the improvement of rooting capacity in trees.

　　This work is supported by the grants from National Key Research and Development Program (2016YFA0500800), National Natural Science Foundation of China (31430013; 31222029; 912173023, 31525004; 31770399) and Strategic Priority Research Program of the Chinese Academy of Sciences (XDB27030101).

　　Link: http://www.plantcell.org/content/early/2019/10/24/tpc.19.00378

　　Contact:

　　Dr. Jia-Wei Wang, Professor

　　National Key Laboratory of Plant Molecular Genetics,CAS Center for Excellence in Molecular Plant Sciences/Shanghai Institute of Plant Physiology and Ecology (SIPPE), Chinese Academic of Sciences

　　Tel: 86-21-54924263

　　Email: jwwang@sippe.ac.cn