scholarly journals OsWRKY5 Promotes Rice Leaf Senescence via Senescence-Associated NAC and Abscisic Acid Biosynthesis Pathway

2019 ◽  
Vol 20 (18) ◽  
pp. 4437 ◽  
Author(s):  
Kim ◽  
Kang ◽  
Kim ◽  
An ◽  
Paek
Keyword(s):  
Abscisic Acid ◽  
Leaf Senescence ◽  
Chlorophyll Degradation ◽  
Regulatory Function ◽  
Abscisic Acid Biosynthesis ◽  
Positive Regulator ◽  
Expression Of Genes ◽  
Dna Insertion ◽  
Aba Biosynthesis ◽  
Endogenous Aba

he onset of leaf senescence is triggered by external cues and internal factors such as phytohormones and signaling pathways involving transcription factors (TFs). Abscisic acid (ABA) strongly induces senescence and endogenous ABA levels are finely tuned by many senescence-associated TFs. Here, we report on the regulatory function of the senescence-induced TF OsWRKY5 TF in rice (Oryza sativa). OsWRKY5 expression was rapidly upregulated in senescing leaves, especially in yellowing sectors initiated by aging or dark treatment. A T-DNA insertion activation-tagged OsWRKY5-overexpressing mutant (termed oswrky5-D) promoted leaf senescence under natural and dark-induced senescence (DIS) conditions. By contrast, a T-DNA insertion oswrky5-knockdown mutant (termed oswrky5) retained leaf greenness during DIS. Reverse-transcription quantitative PCR (RT-qPCR) showed that OsWRKY5 upregulates the expression of genes controlling chlorophyll degradation and leaf senescence. Furthermore, RT-qPCR and yeast one-hybrid analysis demonstrated that OsWRKY5 indirectly upregulates the expression of senescence-associated NAM/ATAF1/2/CUC2 (NAC) genes including OsNAP and OsNAC2. Precocious leaf yellowing in the oswrky5-D mutant might be caused by elevated endogenous ABA concentrations resulting from upregulated expression of ABA biosynthesis genes OsNCED3, OsNCED4, and OsNCED5, indicating that OsWRKY is a positive regulator of ABA biosynthesis during leaf senescence. Furthermore, OsWRKY5 expression was suppressed by ABA treatment. Taken together, OsWRKY5 is a positive regulator of leaf senescence that upregulates senescence-induced NAC, ABA biosynthesis, and chlorophyll degradation genes.

scholarly journals OsWRKY5 Promotes Rice Leaf Senescence by Upregulating Senescence-Associated NAC Genes and Abscisic Acid Biosynthesis

2019 ◽  
Author(s):  
Taehoon Kim ◽  
Kiyoon Kang ◽  
Suk-Hwan Kim ◽  
Gynheung An ◽  
Nam-Chon Paek
Keyword(s):  
Abscisic Acid ◽  
Leaf Senescence ◽  
Chlorophyll Degradation ◽  
Regulatory Function ◽  
Abscisic Acid Biosynthesis ◽  
Negative Feedback Regulation ◽  
Positive Regulator ◽  
Dna Insertion ◽  
Aba Biosynthesis ◽  
Endogenous Aba

The onset of leaf senescence is triggered by external cues and internal factors such as phytohormones and signaling pathways involving transcription factors (TFs). Abscisic acid (ABA) strongly induces senescence and endogenous ABA levels are finely tuned by many senescence-associated TFs. Here, we report on the regulatory function of the senescence-induced TF OsWRKY5 TF in rice (Oryza sativa). OsWRKY5 expression was rapidly upregulated in senescing leaves, especially in yellowing sectors initiated by aging or dark treatment. A T-DNA insertion activation-tagged OsWRKY5-overexpressing mutant (termed oswrky5-D) promoted leaf senescence under natural and dark-induced senescence (DIS) conditions. By contrast, a T-DNA insertion oswrky5-knockdown mutant (termed oswrky5) retained leaf greenness during DIS. Reverse-transcription quantitative PCR (RT-qPCR) showed that OsWRKY5 upregulates the expression of genes controlling chlorophyll degradation and leaf senescence. Furthermore, RT-qPCR and yeast one-hybrid analysis demonstrated that OsWRKY5 indirectly upregulates the expression of senescence-associated NAC genes including OsNAP and OsNAC2. Precocious leaf yellowing in the oswrky5-D mutant might be caused by elevated endogenous ABA concentrations resulting from upregulated expression of ABA biosynthesis genes OsNCED3, OsNCED4, and OsNCED5, indicating that OsWRKY is a positive regulator of ABA biosynthesis during leaf senescence. Furthermore, OsWRKY5 expression was significantly suppressed by ABA treatment, indicating negative feedback regulation of OsWRKY5 expression by ABA. OsWRKY5 is a positive regulator of leaf senescence that upregulates senescence-induced NAC genes leading to expression of ABA biosynthesis and chlorophyll degradation genes.

scholarly journals The Apocarotenoid Zaxinone Is a Positive Regulator of Strigolactone and Abscisic Acid Biosynthesis in Arabidopsis Roots

2020 ◽  
Vol 11 ◽  
Author(s):  
Abdugaffor Ablazov ◽  
Jianing Mi ◽  
Muhammad Jamil ◽  
Kun-Peng Jia ◽  
Jian You Wang ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Acid Biosynthesis ◽  
Abscisic Acid Biosynthesis ◽  
Positive Regulator

Vegetation-derived abscisic acid and four terpenes enforce dormancy in seeds of the post-fire annual,Nicotiana attenuata

2002 ◽  
Vol 12 (4) ◽  
pp. 239-252 ◽  
Author(s):  
Bernd Krock ◽  
Sybille Schmidt ◽  
Christian Hertweck ◽  
Ian T. Baldwin
Keyword(s):  
Abscisic Acid ◽  
Environmental Control ◽  
Wood Smoke ◽  
Nicotiana Attenuata ◽  
Germination Inhibitors ◽  
Physiological Basis ◽  
Fire Environment ◽  
Aba Content ◽  
Aba Biosynthesis ◽  
Endogenous Aba

AbstractThe native tobacco,Nicotiana attenuata, synchronizes its germination with the immediate post-fire environment with a combination of germination stimulants found in wood smoke and inhibitors from the unburned litter of the dominant vegetation. The inhibitors override the stimulants and prevent seeds from germinating maladaptively in unburned habitats adjacent to burns. To understand the physiological basis of this environmental control of germination, we tested several previously isolated signals, phytohormones and their respective biosynthesis inhibitors. The germination inhibitors methyl jasmonate (MeJA, a constituent of sagebrush litter), bornane-2,5-dione (BD, a constituent of juniper litter extract, JLE) and JLE did not alter abscisic acid (ABA) content of imbibed seeds. Treatment with the ABA biosynthesis inhibitor, fluridone, inhibited the dormancy-inducing effects of BD, JLE and MeJA, but surprisingly did not affect endogenous ABA levels in treated seeds. However, ABA leached from litter of the species, which dominate the plant community before fires, plays an important role in germination control. We conclude thatN. attenuataseeds, which can lie dormant in the soil for 150 years between fires, time their germination with the post-fire environment by responding to smoke, ABA and four terpenes (BD, 1,8-cineole, β-thujaplicin and camphor) leaching from the litter of the dominant vegetation.

scholarly journals Triticum Aestivum L. cv. Guizi 1 ANS-6D Positively Regulates Leaf Senescence Through the Abscisic Acid Mediated Chlorophyll Degradation in Tobacco

2021 ◽  
Author(s):  
Luhua Li ◽  
Chang An ◽  
Zhongni Wang ◽  
Fumin Xiong ◽  
Yingxi Wang ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Abscisic Acid ◽  
Leaf Senescence ◽  
Triticum Aestivum L ◽  
Degradation Pathway ◽  
Chlorophyll Degradation ◽  
Anthocyanin Synthesis ◽  
Marker Genes ◽  
Wild Type ◽  
Transgenic Lines

Abstract Anthocyanidin synthase (ANS) is involved in the synthesis of anthocyanins, which are important phytonutrients because of their beneficial effects on human health. Here, we identified ANS-6D of purple-colored Triticum aestivum L. cv. Guizi 1 (Gz) that is involved in leaf senescence through the abscisic acid (ABA) mediated chlorophyll degradation pathway in tobacco. After characterizing the leaf-senescence phenotype in GzANS-6D overexpression (OxGzANS-6D) lines, we found that the increased anthocyanin accumulation and decreased chlorophyll content in OxGzANS-6D lines were closely correlated with the expression levels of anthocyanin synthesis-related structural genes and senescence marker genes, as well as the accumulation of reactive oxygen species. The endogenous ABA content increased and ethylene content decreased in OxGzANS-6D transgenic lines compared with wild type. Additionally, the levels of the abscisic acid-responsive transcription factors ABF1 and ABF2, as well as those of chlorophyll degradation-related genes (PAO, NYC, SGR and CHL), were significantly higher in OxGzANS-6D transgenic lines than in wild type. Furthermore, we found that GzABF1 and NtABF1 binds to the promoter of GzANS-6D, and NtABF2 binds to the promoter of NtSGR. Thus, GzANS-6D participated in leaf senescence through ABA-mediated chlorophyll degradation, and ABF1/2 play important role in GzANS-6D functions.

scholarly journals Abscisic Acid Biosynthesis and Signaling in Plants: Key Targets to Improve Water Use Efficiency and Drought Tolerance

2020 ◽  
Vol 10 (18) ◽  
pp. 6322 ◽  
Author(s):  
Amanda A. Cardoso ◽  
Antonella Gori ◽  
Cristiane J. Da-Silva ◽  
Cecilia Brunetti
Keyword(s):  
Abscisic Acid ◽  
Drought Tolerance ◽  
Water Use Efficiency ◽  
Water Use ◽  
Acid Biosynthesis ◽  
Abscisic Acid Biosynthesis ◽  
Crop Species ◽  
Use Efficiency ◽  
Aba Biosynthesis ◽  
Made In

The observation of a much-improved fitness of wild-type plants over abscisic acid (ABA)-deficient mutants during drought has led researchers from all over to world to perform experiments aiming at a better understanding of how this hormone modulates the physiology of plants under water-limited conditions. More recently, several promising approaches manipulating ABA biosynthesis and signaling have been explored to improve water use efficiency and confer drought tolerance to major crop species. Here, we review recent progress made in the last decade on (i) ABA biosynthesis, (ii) the roles of ABA on plant-water relations and on primary and secondary metabolisms during drought, and (iii) the regulation of ABA levels and perception to improve water use efficiency and drought tolerance in crop species.

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