Global warming has led to an increasing frequency and intensity of extreme high temperature weather. The premature senescence induced by high temperature stress greatly affects the growth and development of plants and the accumulation of biomass. However, the current mechanism of high temperature stress inducing leaf senescence is still lacking Systematic understanding. In addition, the biological clock, as an endogenous timing mechanism in cells, plays an important role in regulating the response of plants to abiotic stress, but whether it is involved in regulating the process of high temperature stress-induced senescence is still unclear.
The research group of Wang Lei, Institute of Botany, Chinese Academy of Sciences, previously discovered that phytochrome interacting factors (PHYTOCHROME INTERACTING FACTOR4/5, PIF4/5) are the direct target genes of the PRR gene family, the core component of the biological clock, and mediate the light of the biological clock on the hypocotyl The regulation of cycle-dependent growth is also a key regulator of plant temperature morphogenesis. In order to further clarify the role of PIF4/5 in temperature stress, the researchers treated Arabidopsis plants at 42oC and found that PIF4/5 mutants significantly delayed the leaf senescence process induced by high temperature stress, while their overexpression plants showed performance The premature senescence phenotype induced by high temperature stress indicates that PIF4/5 participates in the leaf senescence process induced by high temperature. Transcriptomics studies have found that multiple genes related to stress, heat and oxidative stress response, and leaf senescence are differentially expressed in PIF4/5 mutants. The researchers further analyzed the transcriptome and ChIP-seq data and found that NAC019, SAG113, IAA29, CBF2 and BRI1 are the target genes of PIF4/5. The study also found that during the recovery process after high temperature treatment, PIF4 and PIF5 proteins gradually accumulated, and the transcription levels of senescence promoting factors NAC019 and SAG113 also gradually accumulated, while the transcription levels of senescence inhibitor IAA29 gradually decreased, indicating that they may be PIF4 /5 The key target gene that regulates the senescence process induced by high temperature in leaves. Further studies have found that light/dark signals and biological clocks also play an important role in the process of leaf senescence induced by high temperature stress.
Interestingly, under the conditions of 12 hours of light/12 hours of darkness, Arabidopsis thaliana has stronger resistance to leaf senescence induced by high temperature stress during the day; while under continuous light conditions, Arabidopsis leaves senescence The speed is faster in the subjective daytime and slower in the subjective night, indicating that the regulation mechanism of the circadian clock in response to high temperature stress in Arabidopsis to induce leaf senescence does not depend on the light/dark signal of the environment. To sum up, this study analyzed the molecular mechanism of PIF4 and PIF5 regulating high temperature stress-induced leaf senescence, laying a theoretical foundation for further revealing the molecular regulatory network of high temperature stress-induced leaf senescence, and for cultivating high temperature stress to delay senescence. Germplasm materials provide targets for genetic improvement.
The research results were published online in the International Academic Journal Journal of Experimental Botany on April 8. Li Na, a PhD student at the Institute of Botany, Chinese Academy of Sciences, is the first author of this paper, and associate researcher Zhang Yuanyuan and researcher Wang Lei are the co-corresponding authors. The research was funded by the General Program of the National Natural Science Foundation of China, the Strategic Leading Science and Technology Special Project B of the Chinese Academy of Sciences, and the Youth Promotion Association of the Chinese Academy of Sciences.
Link to the paper:https://doi.org/10.1093/jxb/erab158
(Molecular Physiology Laboratory Contribution)
PIFs regulate the molecular mechanism of high temperature stress-induced leaf senescence