The strict regulation of flowering time in 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 unclear.
A recent paper with Dr. Chuanyou Li (Institute of Genetics and Developmental Biology, Chinese Academy of Sciences), a guest professor of Zhejiang University, and Dr. Qiaomei Wang from the Institute of Vegetable Science, Zhejiang University as co-corresponding authors, reported that the COI1-dependent JA signaling pathway delays the flowering time by inhibiting the expression of the florigen gene FT. They have provided genetic and biochemical evidences 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 does not affect JA-regulated defense gene expression and root growth inhibition. This study elucidates the transcriptional mechanism of JA in regulating flowering time and highlights how the specificity of JA responses is determined.
This paper with Dr. Qingzhe Zhai, Xin Zhang and Dr. Fangming Wu as the co-first authors was published online 26 September 2015 in The Plant Cell (DOI:10.1105/tpc.15.00619) . Xin Zhang is a PhD student from Prof. Qiaomei Wang's Lab at the Institute of Vegetable Science, Zhejiang University.
Link: http://www.plantcell.org/content/early/2015/09/28/tpc.15.00619.abstract
