Memory responses of jasmonic acid-associated Arabidopsis genes to a repeated dehydration stress----中国科学院微生物研究所

科研成果

论文题目:	Memory responses of jasmonic acid-associated Arabidopsis genes to a repeated dehydration stress
作者:	Liu, Ning Staswick, Paul E. Avramova, Zoya
联系作者:	Avramova, Zoya*(Zhong Naiqin)
刊物名称:	Plant Cell and Environment
期:
卷:
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年份:	2016
影响因子:	6.443
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摘要:	Dehydration stress activates numerous genes co-regulated by diverse signaling pathways. Upon repeated exposures, however, a subset of these genes does not respond maintaining instead transcription at their initial pre-stressed levels (revised-response' genes). Most of these genes are involved in jasmonic acid (JA) biosynthesis, JA-signaling and JA-mediated stress responses. How these JA-associated genes are regulated to provide different responses to similar dehydration stresses is an enigma. Here, we investigate molecular mechanisms that contribute to this transcriptional behavior. The memory-mechanism is stress-specific: one exposure to dehydration stress or to abscisic acid (ABA) is required to prevent transcription in the second. Both ABA-mediated and JA-mediated pathways are critical for the activation of these genes, but the two signaling pathways interact differently during a single or multiple encounters with dehydration stress. Synthesis of JA during the first (S1) but not the second dehydration stress (S2) accounts for the altered transcriptional responses. We propose a model for these memory responses, wherein lack of MYC2 and of JA synthesis in S2 is responsible for the lack of expression of downstream genes. The similar length of the memory displayed by different memory-type genes suggests biological relevance for transcriptional memory as a gene-regulating mechanism during recurring bouts of drought. Dehydration stress activates transcription from many JA-regulated genes in Arabidopsis. Upon a repeated exposure to dehydration stress, however, a subset of these genes does not respond again but maintain transcription at their initial pre-stressed levels (revised-response' genes). We investigate molecular mechanisms for this transcriptional behavior and found that both ABA-mediated and JA-mediated pathways are critical for the activation of the genes, but the two signaling pathways interact differently in a single and during multiple encounters with dehydration stress. We propose a model, wherein lack of MYC2 and of JA synthesis in a repeated dehydration stress are responsible for the memory responses and suggest biological relevance for the transcriptional memory displayed by JA-regulated genes during recurring bouts of drought.