420 / 2019-01-24 16:41:37

LESION SIMULATING DISEASE 1 serves as a negative regulator of GOLDEN2-LIKE transcription factors in response to salicylic acid

LSD1,GLKs,programmed cell death,Chloroplast,ROS

全体主题 > Abiotic Stress

The transcriptional coregulator LESION SIMULATING DISEASE 1 (LSD1) has been implicated in both biotic and abiotic stresses as a negative regulator of cell death. We previously demonstrated an intracellular signaling pathway from salicylic acid (SA)-triggered upregulation of nuclear genes encoding light-harvesting proteins (LHPs) to chloroplast-mediated stress responses, which largely contributes to the lsd1-conferred runaway cell death (lsd1 RCD). The nuclear-targeted SIGMA FACTOR-BINDING PROTEIN 1 (SIB1), a transcriptional coregulator, was found to interact with GOLDEN2-LIKE transcription factors GLK1 and GLK2 to potentiate the expression of LHPs, leading to the enhanced levels of ROS in chloroplasts of lsd1 mutant plants. We now establish that LSD1 negatively regulates the activity of GLKs via physical interaction and that LSD1-GLK interaction results in the repression of LHPs, downstream target genes of GLKs. Accordingly, overexpression of LSD1 leads to the significant repression of the expression of LHPs, resembling the phenotype observed in glk1 glk2 double mutant plants. Taken together, here we propose that two transcriptional coregulators SIB1 and LSD1, primarily implicated in plant immune responses, may antagonistically regulate the activity of GLKs to finely regulate the expression of LHPs, which might be contributable for maintaining ROS homeostasis in chloroplasts。