Participation of ABA Metabolism and ROS Generation in Sugar Starvation-Induced Senescence of Rice Flag Leaves

Abstract Background: Both sucrose and abscisic acid (ABA) play pivotal role in the regulation of plant leaf senescence. However, the exact mechanism by which sugar starvation , ABA, and reactive oxygen species (ROS) interact with each other during leaf senescence remains largely unknown. In this study, the genotype-dependent alteration in temporal patterns of sugar concentration during leaf senescence and its relation to ABA metabolism and ROS generation were investigated by using the premature senescence of flag leaf ( psf ) mutant and its wild type. Results: Results showed that sugar starvation-induced leaf senescence was closely associated with the endogenous ABA concentration and ROS level in senescent leaves. Sugar starvation accelerated leaf senescence, concomitantly with the marked increase in ABA concentration and malonaldehyde (MDA) accumulation in detached leaves. Conversely, exogenous sugar treatment significantly suppressed the ABA concentration ad ROS level in detached leaves, thus leaf senescence was delayed by exogenous sugar supply. Pharmacological tests revealed that ABA biosynthesis inhibitor (NDGA) delayed the sugar starvation-induced leaf senescence, while ABA catabolism inhibitor (DNCZ) accelerated leaf senescence and significantly increased the endogenous ABA content in senescent leaves. For the expression patterns of ABA synthesis and catabolism related genes induced by sugar starvation, exogenous sucrose supply, NDGA and DNCZ. sugar starvation up-regulated the OsABA8ox1 transcript, while exogenous sucrose and NDGA down-regulated the transciptional expressions of OsNCED1 , OsNCED4 and OsNCED5 and OsABA8ox2 and OsABA8ox3 e by sugar starvation and DNCZ, while the transcript of was increased. Conclusion: Together, our results demonstrated that the rise in endogenous ABA content during sugar starvation-induced leaf senescence is mostly caused by the suppression of ABA catabolism, rather than the enhancement of ABA biosynthesis, and the expression of ABA metabolic genes determines the equilibrium between ABA biosynthesis and catabolism that eventually influence cross-talk between endogenous factors. The breaking for the equilibrium between ABA biosynthesis and catabolism was strongly responsible for sugar starvation-induced leaf senescence, which was resulted from the suppression of ABA catabolism, rather than the enhancement of ABA biosynthesis .

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CCCH protein-PvCCCH69 acted as a repressor for leaf senescence through suppressing ABA-signaling pathway

Horticulture Research ◽

10.1038/s41438-021-00604-0 ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Zheni Xie ◽

Guohui Yu ◽

Shanshan Lei ◽

Chenchen Zhang ◽

Bin Xu ◽

...

Keyword(s):

Leaf Senescence ◽

Panicum Virgatum ◽

Aba Signaling ◽

Light Harvesting Complex ◽

Photosynthetic Proteins ◽

Growth Development ◽

Aba Content ◽

Aba Biosynthesis ◽

Senescence Associated Genes ◽

Endogenous Aba

AbstractCCCH is a subfamily of zinc finger proteins involved in plant growth, development, and stresses response. The function of CCCH in regulating leaf senescence, especially its roles in abscisic acid (ABA)-mediated leaf senescence is largely unknown. The objective of this study was to determine functions and mechanisms of CCCH gene in regulating leaf senescence in switchgrass (Panicum virgatum). A CCCH gene, PvCCCH69 (PvC3H69), was cloned from switchgrass. Overexpressing PvC3H69 in rice suppressed both natural senescence with leaf aging and dark-induced leaf senescence. Endogenous ABA content, ABA biosynthesis genes (NCED3, NCED5, and AAO3), and ABA signaling-related genes (SnRKs, ABI5, and ABF2/3/4) exhibited significantly lower levels in senescencing leaves of PvC3H69-OE plants than those in WT plants. PvC3H69-suppression of leaf senescence was associated with transcriptional upregulation of genes mainly involved in the light-dependent process of photosynthesis, including light-harvesting complex proteins, PSI proteins, and PSII proteins and downregulation of ABA biosynthesis and signaling genes and senescence-associated genes. PvC3H69 could act as a repressor for leaf senescence via upregulating photosynthetic proteins and repressing ABA synthesis and ABA signaling pathways.

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

Seed Science Research ◽

10.1079/ssr2002117 ◽

2002 ◽

Vol 12 (4) ◽

pp. 239-252 ◽

Cited By ~ 31

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.

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

10.20944/preprints201908.0189.v1 ◽

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.

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Functional Identification of 9-cis-epoxycarotenoid Dioxygenase Genes in Double Dormant Plant-herbaceous Peony

10.21203/rs.3.rs-1176350/v1 ◽

2021 ◽

Author(s):

Riwen Fei ◽

Siyang Duan ◽

Jiayuan Ge ◽

Tianyi Sun ◽

Xiaomei Sun

Keyword(s):

Seed Dormancy ◽

Dormancy Release ◽

Transcriptome Data ◽

Functional Identification ◽

Internal Factors ◽

Herbaceous Peony ◽

Aba Metabolism ◽

Complex Process ◽

Aba Content ◽

Endogenous Aba

Abstract Seed dormancy and germination is a complex process, which is affected by external environmental conditions and internal factors independently or mutually. Phytohormones play an important regulatory role in this process. ABA was the main phytohormone affecting herbaceous peony seed dormancy release. However, the mechanism of ABA in the dormancy release of herbaceous peony needs to be further explored. Here, transcriptome data was screened from the perspective of ABA metabolism, and significantly differentially expressed PlNCED1 and PlNCED2 were obtained. We found that their expression trends were positively correlated with ABA content. Among them, PlNCED2 had a stronger regulatory effect on ABA content and was more sensitive to exogenous ABA. Overexpression and silencing of PlNCEDs in callus could affect the expression of PlCYP707As and the content of endogenous ABA. Through the observation of seed germination of Arabidopsis thaliana (A. thaliana), we found PlNCED1 and PlNCED2 promoted seed dormancy, and the promotion effect of PlNCED2 was more obvious. In general, PlNCED1 and PlNCED2 participated in the dormancy release of herbaceous peony seeds by regulating the accumulation of endogenous ABA. Our work can reveal the molecular mechanism and related theories of ABA involved in herbaceous peony seed dormancy release.

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Contribution of ABA metabolism and ROS generation to sugar starvation-induced senescence of rice leaves

Plant Growth Regulation ◽

10.1007/s10725-021-00718-4 ◽

2021 ◽

Author(s):

Muhmmad Asad Ullah Asad ◽

Fubiao Wang ◽

Yu Ye ◽

Xianyue Guan ◽

Lujian Zhou ◽

...

Keyword(s):

Ros Generation ◽

Sugar Starvation ◽

Aba Metabolism ◽

Rice Leaves

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Tomato mutants sensitive to abiotic stress display different abscisic acid content and metabolism during germination

Seed Science Research ◽

10.1017/s0960258508096219 ◽

2008 ◽

Vol 18 (4) ◽

pp. 249-258 ◽

Cited By ~ 2

Author(s):

Andrea Andrade ◽

Oscar Masciarelli ◽

Sergio Alemano ◽

Virginia Luna ◽

Guillermina Abdala

Keyword(s):

Abscisic Acid ◽

Abiotic Stress ◽

Solanum Lycopersicum ◽

Wild Type ◽

Aba Metabolism ◽

Germination Process ◽

Aba Catabolism ◽

Aba Content ◽

Abscisic Acid Content

AbstractWe report the determination of abscisic acid (ABA) and its metabolites, phaseic acid (PA), dihydrophaseic acid (DPA) and ABA glucose ester (ABA-GE), in non-dormant dry and imbibed seeds of tomato (Solanum lycopersicumMill.) cv. Moneymaker (wild type), and itstss1,tss2andtos1mutants. High ABA in dry seeds may originate from ABA accumulation in the sheath tissue, which was in contact with an ABA-containing medium, the endocarpus. The highest germination percentages at 72 h, observed intss1andtss2, coincided with minimal ABA content. Wild-type and mutant seeds showed different ABA and catabolic patterns, and these were correlated with their sensitivity to abiotic stress. Whereas dry seeds showed a high basal ABA, imbibed seeds showed higher ABA metabolite content, particularly DPA. The dramatic decrease of ABA following seed imbibition suggests an activation of ABA catabolism during the early stages of the germination process. The observed variation of ABA metabolites among dry and imbibed seeds ofSolanum lycopersicumcv. Moneymaker and itstss1,tss2andtos1mutants shows that ABA metabolism is differentially regulated in these genotypes.

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

International Journal of Molecular Sciences ◽

10.3390/ijms20184437 ◽

2019 ◽

Vol 20 (18) ◽

pp. 4437 ◽

Cited By ~ 5

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.

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Influence of γ-irradiation on the expression of encoding ABA metabolism enzymes in barley embryos

Ecological genetics ◽

10.17816/ecogen16485-89 ◽

2018 ◽

Vol 16 (4) ◽

pp. 85-89

Author(s):

Sofia V. Bitarishvili ◽

Vladimir S. Bondarenko ◽

Stanislav A. Geras’kin

Keyword(s):

Dose Range ◽

Γ Irradiation ◽

Aba Metabolism ◽

Expression Of Genes ◽

Metabolism Enzymes ◽

Small Doses ◽

Genes Encoding ◽

Aba Content ◽

Aba Biosynthesis ◽

Relative Gene

Background. Small doses of radiation stimulate the growth and development of plants including seed germination. ABA plays a key role not only in seed dormancy and germination but also in the regulation of adaptive reactions of plants. The aim of our work was to study the effect of γ-irradiation of barley seeds in a small doses on the expression of genes encoding ABA biosynthesis enzyme 9-cis-epoxycarotenoid dioxygenase (HvNCED1) and catabolism enzyme ABA 8’-hydroxylase (HvABA8’OH-1). Materials and Methods. The barley seeds were irradiated at dose range of 4–50 Gy at a dose rate of 60 Gy/h, the radiation source was 60Co. The study was carried out in the embryos within the first 30 hours after germination. Relative gene expression was investigated using real-time PCR (RT-PCR). Results. It was shown that γ-irradiation of barley seeds changes the expression of ABA biosynthesis and catabolism genes in all experimental groups. Conclusion. This alterations can lead to a decrease the ABA content under irradiation with stimulating doses and increase the biosynthesis of phytohormone under irradiation with inhibitory dose.

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