scholarly journals The leaf senescence-promoting transcription factor AtNAP activates its direct target gene CYTOKININ OXIDASE 3 to facilitate senescence processes by degrading cytokinins

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Youzhen Hu ◽  
Bin Liu ◽  
Huazhong Ren ◽  
Liping Chen ◽  
Christopher B. Watkins ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Leaf Senescence ◽  
Plant Hormones ◽  
Cytokinin Oxidase ◽  
In Planta ◽  
Delayed Senescence ◽  
Lateral Bud ◽  
Direct Target Gene ◽  
Fountain Of Youth ◽  
Senescence Phenotype

AbstractCytokinins (CKs) are a class of adenine-derived plant hormones that plays pervasive roles in plant growth and development including cell division, morphogenesis, lateral bud outgrowth, leaf expansion and senescence. CKs as a “fountain of youth” prolongs leaf longevity by inhibiting leaf senescence, and therefore must be catabolized for senescence to occur. AtNAP, a senescence-specific transcription factor has a key role in promoting leaf senescence. The role of AtNAP in regulating CK catabolism is unknown. Here we report the identification and characterization of AtNAP-AtCKX3 (cytokinin oxidase 3) module by which CKs are catabolized during leaf senescence in Arabidopsis. Like AtNAP, AtCKX3 is highly upregulated during leaf senescence. When AtNAP is chemically induced AtCKX3 is co-induced; and when AtNAP is knocked out, the expression of AtCKX3 is abolished. AtNAP physically binds to the cis element of the AtCKX3 promoter to direct its expression as revealed by yeast one-hybrid assays and in planta experiments. Leaves of the atckx3 knockout lines have higher CK concentrations and a delayed senescence phenotype compared with those of WT. In contrast, leaves with inducible expression of AtCKX3 have lower CK concentrations and exhibit a precocious senescence phenotype compared with WT. This research reveals that AtNAP transcription factor˗AtCKX3 module regulates leaf senescence by connecting two antagonist plant hormones abscisic acid and CKs.

scholarly journals Ring/U-Box Protein AtUSR1 Functions in Promoting Leaf Senescence Through JA Signaling Pathway in Arabidopsis

2020 ◽  
Vol 11 ◽  
Author(s):  
Zenglin Zhang ◽  
Mengmeng Xu ◽  
Yongfeng Guo
Keyword(s):  
Transcription Factor ◽  
Signaling Pathway ◽  
Leaf Senescence ◽  
Luciferase Assay ◽  
Significant Delay ◽  
Delayed Senescence ◽  
Age Dependent ◽  
Ja Signaling ◽  
Senescence Phenotype

Leaf senescence is regulated by a large number of internal and environmental factors. Here, we report that AtUSR1 (U-box Senescence Related 1) which encodes a plant Ring/U-box protein, is involved in age-dependent and dark-induced leaf senescence in Arabidopsis. Expression of AtUSR1 gene in leaves was up-regulated in darkness and during aging. Plants of usr1, an AtUSR1 gene knock-down mutant, showed a significant delay in age-dependent and dark-induced leaf senescence and the delayed senescence phenotype was rescued when the AtUSR1 gene was transferred back to the mutant plants. Meanwhile, overexpression of AtUSR1 caused accelerated leaf senescence. Furthermore, the role of AtUSR1 in regulating leaf senescence is related to MYC2-mediuated jasmonic acid (JA) signaling pathway. MeJA treatments promoted the accumulation of AtUSR1 transcripts and this expression activation was dependent on the function of MYC2, a key transcription factor in JA signaling. Dual-luciferase assay results indicated that MYC2 promoted the expression of AtUSR1. Overexpression of AtUSR1 in myc2 mutant plants showed precocious senescence, while myc2 mutation alone caused a delay in leaf senescence, suggesting that AtUSR1 functions downstream to MYC2 in the JA signaling pathway in promoting leaf senescence.

scholarly journals The NAC transcription factor ANAC046 is a positive regulator of chlorophyll degradation and senescence in Arabidopsis leaves

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Chihiro Oda-Yamamizo ◽  
Nobutaka Mitsuda ◽  
Shingo Sakamoto ◽  
Daisuke Ogawa ◽  
Masaru Ohme-Takagi ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transgenic Plants ◽  
Leaf Senescence ◽  
Loss Of Function ◽  
Pheophorbide A ◽  
Delayed Senescence ◽  
Positive Regulator ◽  
Catabolic Genes ◽  
Senescence Associated Genes ◽  
Senescence Phenotype

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.

scholarly journals Drought-induced Leaf Senescence and Horticultural Performance of Transgenic PSAG12-IPT Petunias

2004 ◽  
Vol 129 (1) ◽  
pp. 93-99 ◽  
Author(s):  
David G. Clark ◽  
Chris Dervinis ◽  
James E. Barrett ◽  
Harry Klee ◽  
Michelle Jones
Keyword(s):  
Transgenic Plants ◽  
Leaf Senescence ◽  
Plant Morphology ◽  
Fold Increase ◽  
Transcript Abundance ◽  
Plant Production ◽  
Mrna Levels ◽  
Delayed Senescence ◽  
Transgenic Lines ◽  
Senescence Phenotype

Cytokinins have been shown to delay the onset of leaf senescence. The focus of this project was to produce transgenic petunia (Petunia ×hybrida) plants that over-produced endogenous cytokinins in a senescence specific manner. This was achieved by transforming plants with the IPT (isopentenyl transferase) gene driven by the senescence-associated transcriptional promoter, PSAG12. Two independent transgenic events produced T1 and T2 generation seedling lines that demonstrated the desired nonsenescent phenotype in progeny trials. These lines were used to evaluate the horticultural performance of PSAG12-IPT petunia plants in terms of delayed senescence, rooting of vegetative cuttings, lateral branch growth, flower number, floral timing, and fruit set. Although both lines displayed a delayed senescence phenotype the two PSAG12-IPT transgenic lines differed from each other in regard to other horticultural traits. In addition to delayed leaf senescence, line I-1-7 also demonstrated a decrease in adventitious rooting and an increased number of branches during plant production. Line I-3-18 also demonstrated a delayed leaf senescence phenotype; however, plants of this line were not greatly altered in any other horticultural performance traits in comparison to wild-type `V26'. IPT transcript was detected in young fully expanded leaves of both lines, although mRNA levels were higher in I-1-7 plants. A greater than 50-fold increase in IPT transcript abundance was detected in leaves of transgenic plants following drought stress. These results demonstrate that it is possible to use PSAG12-IPT to produce transgenic plants with delayed leaf senescence but differences in plant morphology between transgenic lines exist, which may alter horticultural performance characteristics.

scholarly journals A combinatorial action of GmMYB176 and GmbZIP5 controls isoflavonoid biosynthesis in soybean (Glycine max)

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Arun Kumaran Anguraj Vadivel ◽  
Tim McDowell ◽  
Justin B. Renaud ◽  
Sangeeta Dhaubhadel
Keyword(s):  
Transcription Factor ◽  
Hairy Roots ◽  
Defense Mechanisms ◽  
Biosynthetic Pathway ◽  
Bzip Transcription Factor ◽  
Myb Transcription Factor ◽  
In Planta ◽  
Rnai Silencing ◽  
Protein Protein Interaction ◽  
Soybean Roots

AbstractGmMYB176 is an R1 MYB transcription factor that regulates multiple genes in the isoflavonoid biosynthetic pathway, thereby affecting their levels in soybean roots. While GmMYB176 is important for isoflavonoid synthesis, it is not sufficient for the function and requires additional cofactor(s). The aim of this study was to identify the GmMYB176 interactome for the regulation of isoflavonoid biosynthesis in soybean. Here, we demonstrate that a bZIP transcription factor GmbZIP5 co-immunoprecipitates with GmMYB176 and shows protein–protein interaction in planta. RNAi silencing of GmbZIP5 reduced the isoflavonoid level in soybean hairy roots. Furthermore, co-overexpression of GmMYB176 and GmbZIP5 enhanced the level of multiple isoflavonoid phytoallexins including glyceollin, isowighteone and a unique O-methylhydroxy isoflavone in soybean hairy roots. These findings could be utilized to develop biotechnological strategies to manipulate the metabolite levels either to enhance plant defense mechanisms or for human health benefits in soybean or other economically important crops.

scholarly journals The apple C2H2-type zinc finger transcription factor MdZAT10 positively regulates JA-induced leaf senescence by interacting with MdBT2

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Kuo Yang ◽  
Jian-Ping An ◽  
Chong-Yang Li ◽  
Xue-Na Shen ◽  
Ya-Jing Liu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Transcription Factor ◽  
Liquid Chromatography ◽  
Zinc Finger ◽  
Leaf Senescence ◽  
Transcriptional Activity ◽  
Molecular Mechanisms ◽  
Liquid Chromatography Mass Spectrometry ◽  
Zinc Finger Transcription Factor ◽  
Insight Into

AbstractJasmonic acid (JA) plays an important role in regulating leaf senescence. However, the molecular mechanisms of leaf senescence in apple (Malus domestica) remain elusive. In this study, we found that MdZAT10, a C2H2-type zinc finger transcription factor (TF) in apple, markedly accelerates leaf senescence and increases the expression of senescence-related genes. To explore how MdZAT10 promotes leaf senescence, we carried out liquid chromatography/mass spectrometry screening. We found that MdABI5 physically interacts with MdZAT10. MdABI5, an important positive regulator of leaf senescence, significantly accelerated leaf senescence in apple. MdZAT10 was found to enhance the transcriptional activity of MdABI5 for MdNYC1 and MdNYE1, thus accelerating leaf senescence. In addition, we found that MdZAT10 expression was induced by methyl jasmonate (MeJA), which accelerated JA-induced leaf senescence. We also found that the JA-responsive protein MdBT2 directly interacts with MdZAT10 and reduces its protein stability through ubiquitination and degradation, thereby delaying MdZAT10-mediated leaf senescence. Taken together, our results provide new insight into the mechanisms by which MdZAT10 positively regulates JA-induced leaf senescence in apple.

Involvement of NAC transcription factor SiNAC1 in a positive feedback loop via ABA biosynthesis and leaf senescence in foxtail millet

Planta ◽  
2017 ◽  
Vol 247 (1) ◽  
pp. 53-68 ◽  
Author(s):  
Tingting Ren ◽  
Jiawei Wang ◽  
Mingming Zhao ◽  
Xiaoming Gong ◽  
Shuxia Wang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Leaf Senescence ◽  
Positive Feedback ◽  
Feedback Loop ◽  
Foxtail Millet ◽  
Nac Transcription Factor ◽  
Positive Feedback Loop ◽  
Aba Biosynthesis

Roles of potential plant hormones and transcription factors in controlling leaf senescence and drought tolerance

PROTOPLASMA ◽  
2018 ◽  
Vol 256 (2) ◽  
pp. 313-329 ◽  
Author(s):  
Sumira Jan ◽  
Nazia Abbas ◽  
Muhammad Ashraf ◽  
Parvaiz Ahmad
Keyword(s):  
Transcription Factors ◽  
Drought Tolerance ◽  
Leaf Senescence ◽  
Plant Hormones

scholarly journals Expression of the ToxA and PtrPf2 genes of the phytopathogenic fungus Pyrenophora tritici-repentis at the beginning of the infection process

2019 ◽  
Author(s):  
Nina V. Mironenko ◽  
Alexandra S. Orina ◽  
Nadezhda M. Kovalenko
Keyword(s):  
Transcription Factor ◽  
Wheat Variety ◽  
Infection Process ◽  
Phytopathogenic Fungus ◽  
In Planta ◽  
Effector Gene ◽  
Pyrenophora Tritici Repentis ◽  
Wheat Leaves ◽  
Necrotrophic Effector

This study shows that the necrotrophic effector gene ToxA is differentially expressed in isolates of P. tritici-repentis fungus at different time periods after inoculation of the wheat variety Glenlea which has the gene Tsn1 controlling sensitivity to the necrosis inducing toxin Ptr ToxA. Two P. tritici-repentis isolates with different ability to cause necrosis on the leaves of Glenlea variety (nec + and nec-) and with different expression level of ToxA and gene of factor transcription PtrPf2 in vitro were used for analysis. Isolates of P. tritici-repentis are characterized by the differential expression of ToxA in planta. The expression of the ToxA gene in P. tritici-repentis ToxA+ isolates significantly increased when infected the wheat leaves compared to ToxA expression results obtained in vitro. The levels of ToxA expression in both isolates differed significantly after 24, 48 and 96 hours after inoculation, however, the dynamics of the trait change over time were similar. However, the highest ToxA expression in the virulent (nec+) isolate in contrast with the avirulent (nec-) isolate was observed at a point of 48 hours. Whereas the expression of regulating transcription factor PtrPf2 in planta differed imperceptibly from expression in vitro throughout the observation period. Obviously, the role of the fungal transcription factor in regulating the effector gene expression weakens in planta, and other mechanisms regulating the expression of pathogen genes at the biotrophic stage of the disease develop.

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