The strict regulation of flowering time of higher plants is essential for reproductive success, enabling completion of seed development in favorable environmental conditions. The timing of flowering is coordinately controlled by various endogenous and environmental signals. Besides being a key immune signal, the lipid-derived plant hormone jasmonate (JA) also regulates a wide range of developmental processes including flowering time. Although JA has been implicated in regulating flowering time in several plant species, the exact role of JA in regulating this important physiological process and the underlying molecular mechanism remains obscure.

Scientists in Dr. LI Chuanyou’s group from the Institute of Genetics and Development Biology, the Chinese Academy of Sciences, reported that the COI1-dependent signaling pathway delayed the flowering time of Arabidopsis by inhibiting the expression of the florigen gene FT. They provided genetic and biochemical evidence that the AP2 transcription factors TOE1 and TOE2 interact with a subset of JAZ proteins and repress the transcription of FT.

 

Their research supports a scenario that, when plants encounter stress conditions, bioactive JA promotes COI1-dependent degradation of JAZs. Degradation of the JAZ repressors liberates the transcriptional function of TOEs to repress the expression of FT and thereby triggers the signaling cascades to delay flowering. Significantly, they found that the TOE-JAZ interaction complex is specifically involved in JA-dependent flowering regulation, but dose not affect JA-regulated defense gene expression and root growth inhibition.

 

This study uncovers the transcriptional mechanism of JA in regulating flowering time and highlights how the specificity of JA responses is determined.

 

This work with ZHAI Qingzhe, ZHANG Xin and WU Fangming as the co-first authors has been published in The Plant Cell(http://www.plantcell.org/content/early/2015/09/28/tpc.15.00619). This research was supported by the National Basic Research Program of China, the Strategic Priority Research Program of the Chinese Academy of Sciences, the National Natural Science Foundation of China and the State Key Laboratory of Plant Genomics.

 

AUTHOR CONTACT:

LI Chuanyou, Group Leader

Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.

E-mail: cyli@genetics.ac.cn

 

 

 

Figure. COI1-dependent signaling pathway delays the flowering time by regulating the expression of FT. (Image by IGDB)