Gibberellins (GAs) modulate jasmonate (JA) signaling

Gibberellins (GAs) modulate jasmonate (JA) signaling, which is essential for stress response and development of plants. However, the molecular details of such phytohormone interaction remain largely unknown.

Dr. XIA Kuafei from Sustainable Use of Plant and Gene Resource Field in South China Botanical Garden, CAS and postdoctor HOU Xingliang from Plant Functional Genomics Lab in National University of Singapore worked together in the research of reciprocity of proteins JA ZIM-domain 1 (JAZ1), DELLA, MYC2 and GA. A great progress achieved on this field recently. The results show that the JA ZIM-domain 1 (JAZ1) protein, a key repressor of JA signaling, interacts in vivo with DELLA proteins, repressors of the GA pathway. DELLAs prevent inhibitory JAZ1 interaction with a key transcriptional activator of JA responses, MYC2, and, thus, enhance the ability of MYC2 to regulate its target genes. Conversely, GA triggers degradation of DELLAs, which allows JAZ1 to bind MYC2 and suppress MYC2-dependent JA signaling outputs. Therefore, our results reveal one means by which GAs suppress cellular competence to respond to JA. Because DELLAs serve as central regulators that mediate the crosstalk of various phytohormones, our mode lalso suggests a candidate mechanism by which JA signaling may be fine-tuned by other signaling pathways through DELLAs.

The results has been published in the important international journal Developmental Cell (DOI 10.1016/j.devcel. 2010.10.024).

A "Relief of Repression" Model Describing that DELLAs Modulate JA Signaling via Competitive Binding to JAZs