scholarly journals ABF2, ABF3, and ABF4 Promote ABA-Mediated Chlorophyll Degradation and Leaf Senescence by Transcriptional Activation of Chlorophyll Catabolic Genes and Senescence-Associated Genes in Arabidopsis

2016 ◽  
Vol 9 (9) ◽  
pp. 1272-1285 ◽  
Author(s):  
Shan Gao ◽  
Jiong Gao ◽  
Xiaoyu Zhu ◽  
Yi Song ◽  
Zhongpeng Li ◽  
...  
2019 ◽  
Vol 20 (16) ◽  
pp. 3860
Author(s):  
Xian-mei Xiao ◽  
Yan-mei Xu ◽  
Ze-xiang Zeng ◽  
Xiao-li Tan ◽  
Zong-li Liu ◽  
...  

Several lines of evidence have implicated the involvement of the phytohormone gibberellin (GA) in modulating leaf senescence in plants. However, upstream transcription factors (TFs) that regulate GA biosynthesis in association with GA-mediated leaf senescence remain elusive. In the current study, we report the possible involvement of a TEOSINTE BRANCHED1/CYCLOIDEA/PCF (TCP) TF BrTCP21 in GA-delayed leaf senescence in Chinese flowering cabbage. Exogenous GA3 treatment maintained a higher value of maximum PSII quantum yield (Fv/Fm) and total chlorophyll content, accompanied by the repression of the expression of senescence-associated genes and chlorophyll catabolic genes, which led to the delay of leaf senescence. A class I member of TCP TFs BrTCP21, was further isolated and characterized. The transcript level of BrTCP21 was low in senescing leaves, and decreased following leaf senescence, while GA3 could keep a higher expression level of BrTCP21. BrTCP21 was further found to be a nuclear protein and exhibit trans-activation ability through transient-expression analysis in tobacco leaves. Intriguingly, the electrophoretic mobility shift assay (EMSA) and transient expression assay illustrated that BrTCP21 bound to the promoter region of a GA biosynthetic gene BrGA20ox3, and activated its transcription. Collectively, these observations reveal that BrTCP21 is associated with GA-delayed leaf senescence, at least partly through the activation of the GA biosynthetic pathway. These findings expand our knowledge on the transcriptional mechanism of GA-mediated leaf senescence.


2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Chihiro Oda-Yamamizo ◽  
Nobutaka Mitsuda ◽  
Shingo Sakamoto ◽  
Daisuke Ogawa ◽  
Masaru Ohme-Takagi ◽  
...  

Abstract Chlorophyll (Chl) degradation occurs during leaf senescence, embryo degreening, bud breaking, and fruit ripening. The Chl catabolic pathway has been intensively studied and nearly all the enzymes involved are identified and characterized; however, the molecular regulatory mechanisms of this pathway are largely unknown. In this study, we performed yeast one-hybrid screening using a transcription factor cDNA library to search for factors controlling the expression of Chl catabolic genes. We identified ANAC046 as a common regulator that directly binds to the promoter regions of NON-YELLOW COLORING1, STAY-GREEN1 (SGR1), SGR2, and PHEOPHORBIDE a OXYGENASE. Transgenic plants overexpressing ANAC046 exhibited an early-senescence phenotype and a lower Chl content in comparison with the wild-type plants, whereas loss-of-function mutants exhibited a delayed-senescence phenotype and a higher Chl content. Microarray analysis of ANAC046 transgenic plants showed that not only Chl catabolic genes but also senescence-associated genes were positively regulated by ANAC046. We conclude that ANAC046 is a positive regulator of Arabidopsis leaf senescence and exerts its effect by controlling the expression of Chl catabolic genes and senescence-associated genes.


2019 ◽  
Vol 20 (2) ◽  
pp. 256 ◽  
Author(s):  
Muhammad Asad ◽  
Shamsu Zakari ◽  
Qian Zhao ◽  
Lujian Zhou ◽  
Yu Ye ◽  
...  

Abiotic stresses trigger premature leaf senescence by affecting some endogenous factors, which is an important limitation for plant growth and grain yield. Among these endogenous factors that regulate leaf senescence, abscisic acid (ABA) works as a link between the oxidase damage of cellular structure and signal molecules responding to abiotic stress during leaf senescence. Considering the importance of ABA, we collect the latest findings related to ABA biosynthesis, ABA signaling, and its inhibitory effect on chloroplast structure destruction, chlorophyll (Chl) degradation, and photosynthesis reduction. Post-translational changes in leaf senescence end with the exhaustion of nutrients, yellowing of leaves, and death of senescent tissues. In this article, we review the literature on the ABA-inducing leaf senescence mechanism in rice and Arabidopsis starting from ABA synthesis, transport, signaling receptors, and catabolism. We also predict the future outcomes of investigations related to other plants. Before changes in translation occur, ABA signaling that mediates the expression of NYC, bZIP, and WRKY transcription factors (TFs) has been investigated to explain the inducing effect on senescence-associated genes. Various factors related to calcium signaling, reactive oxygen species (ROS) production, and protein degradation are elaborated, and research gaps and potential prospects are presented. Examples of gene mutation conferring the delay or induction of leaf senescence are also described, and they may be helpful in understanding the inhibitory effect of abiotic stresses and effective measures to tolerate, minimize, or resist their inducing effect on leaf senescence.


2019 ◽  
Vol 39 (1) ◽  
pp. 75-87 ◽  
Author(s):  
Wei Lei ◽  
Yan Li ◽  
Xiuhong Yao ◽  
Kang Qiao ◽  
Lin Wei ◽  
...  

2007 ◽  
Vol 144 (3) ◽  
pp. 1429-1441 ◽  
Author(s):  
Guodong Ren ◽  
Kun An ◽  
Yang Liao ◽  
Xiao Zhou ◽  
Yajun Cao ◽  
...  

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