Melatonin delays leaf senescence of Chinese flowering cabbage by suppressing ABFs‐mediated abscisic acid biosynthesis and chlorophyll degradation

2019 ◽  
pp. e12570 ◽  
Author(s):  
Xiao‐Li Tan ◽  
Zhong‐qi Fan ◽  
Jian‐fei Kuang ◽  
Wang‐jin Lu ◽  
Russel J. Reiter ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Leaf Senescence ◽  
Chlorophyll Degradation ◽  
Acid Biosynthesis ◽  
Abscisic Acid Biosynthesis

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 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.

Biosynthesis of abscisic acid

1983 ◽  
Vol 11 (5) ◽  
pp. 553-557 ◽  
Author(s):  
R. HORGAN ◽  
S. J. NEILL ◽  
D. C. WALTON ◽  
D. GRIFFIN
Keyword(s):  
Acetic Acid ◽  
Abscisic Acid ◽  
Model System ◽  
Acid Biosynthesis ◽  
Abscisic Acid Biosynthesis ◽  
Preliminary Results ◽  
Endogenous Compounds

The fungus Cercospora rosicola has been studied as a model system for abscisic acid biosynthesis. 1′-Deoxyabscisic acid and 4′-hydroxy-α-ionylidene acetic acid have been identified as endogenous compounds in this fungus. The results of feeding these and other putative intermediates suggest that abscisic acid biosynthesis proceeds via the successive oxidations of a 3 -methyl- 5 - (2′,6′,6′- trimethylcyclohex-2′-en-1′-yl)- 2,4-pentadienyl intermediate. Preliminary results suggest that a similar pathway may operate in plants.

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