Current Understanding of Leaf Senescence in Rice

Lee, Sichul; Masclaux-Daubresse, Céline

doi:10.3390/ijms22094515

Cited by 65 publications

(47 citation statements)

References 146 publications

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“…Many studies have demonstrated that hormonal changes at the whole-plant level can regulate senescence and nutrient remobilization (Davies, 1995;Lee and Masclaux-Daubresse, 2021). Abiotic stresses also affect hormonal levels, potentially regulating seed development and nutrient mobility (Ober et al, 1991;Davies, 1995;Wang et al, 2006).…”

Section: Npf and Lt Suppressed Grain Filling Related Characteristicsmentioning

confidence: 99%

Super Rice With High Sink Activities Has Superior Adaptability to Low Filling Stage Temperature

Xu¹,

Yang

Tang³

et al. 2021

Front. Plant Sci.

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To investigate the differential responses of super rice grain filling to low filling stage temperature (LT) and the regulative effect of nitrogen panicle fertilizer (NPF), physiological and molecular experiments were conducted with two super rice varieties (Nanjing 7th: N7 and Nanjing 9108th: N9108) on two different filling stage temperature treatments implemented by applying two sowing dates [Normal filling stage temperature (CK): Sowed on May 30, Tmean = 24.7°C and low filling stage temperature (LT): Sowed on July 1, Tmean = 20.3°C], and two NPF levels (0 and 150 kg N ha−1). In this study, LT, NPF, and simultaneous LT and NPF treatments suppressed the grain filling in all varieties with different levels. Under LT or NPF treatments, the reduction of grain weight, seed setting rate, and filling rate were closely associated with suppressed starch biosynthesis rate in inferior seeds, suggesting that reduced starch biosynthesis rate, expression, and activities of enzymes encoded by related genes, Floury endosperm-4 (FLO4), Starch branching enzyme-I (SBE1), and Starch phosphorylase-L (PHO-l), were responsible for the grain filling reduction. Under LT or NPF treatments, significantly higher grain filling rates and lower variance were found in N9108 compared to that in N7, which were closely related to their higher starch biosynthesis ability, related gene expression, and enzymes activities. One of the probable explanations of the grain filling difference was the variation in the relative amount of key regulative hormones, Abscisic acid (ABA) and 1-aminocyclopropane-1-carboxylic acid (ACC). These results raise a possibility that super rice with higher sink activities has superior adaptability to LT and NPF due to their higher sink activities.

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Section: Npf and Lt Suppressed Grain Filling Related Characteristicsmentioning

confidence: 99%

Super Rice With High Sink Activities Has Superior Adaptability to Low Filling Stage Temperature

Xu¹,

Yang

Tang³

et al. 2021

Front. Plant Sci.

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“…Leaf senescence is the last stage of plant growth, and is affected by various genetic and environmental constraints [ 42 ]. Leaf yellowing is a visible symptom of senescence that is caused by loss of the green pigment chlorophyll (Chl) [ 42 ].…”

Section: Discussionmentioning

confidence: 99%

Mathematical Modeling Reveals That Sucrose Regulates Leaf Senescence via Dynamic Sugar Signaling Pathways

Asim

Hussain

Wang

et al. 2022

IJMS

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Sucrose (Suc) accumulation is one of the key indicators of leaf senescence onset, but little is known about its regulatory role. Here, we found that application of high (120–150 mM) and low levels (60 mM) of Suc to young leaf (YL) and fully expanded leaf (FEL) discs, respectively, decreased chlorophyll content and maximum photosynthetic efficiency. Electrolyte leakage and malondialdehyde levels increased at high Suc concentrations (90–120 mM in YL and 60 and 150 mM in FEL discs). In FEL discs, the senescence-associated gene NtSAG12 showed a gradual increase in expression with increased Suc application; in contrast, in YL discs, NtSAG12 was upregulated with low Suc treatment (60 mM) but downregulated at higher levels of Suc. In YL discs, trehalose-6-phosphate (T6P) accumulated at a low half-maximal effective concentration (EC50) of Suc (1.765 mM). However, T6P levels declined as trehalose 6 phosphate synthase (TPS) content decreased, resulting in the maximum velocity of sucrose non-fermenting-1-related protein kinase (SnRK) and hexokinase (HXK) occurring at higher level of Suc. We therefore speculated that senescence was induced by hexose accumulation. In FEL discs, the EC50 of T6P occurred at a low concentration of Suc (0.9488 mM); T6P levels progressively increased with higher TPS content, which inhibited SnRK activity with a dissociation constant (Kd) of 0.001475 U/g. This confirmed that the T6P–SnRK complex induced senescence in detached FEL discs.

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“…So far, many SAGs have been characterized in rice. They are involved in nutrient relocation, macromolecules degradation, transcriptional regulation, and signal transduction (Lee and Masclaux-Daubresse, 2021). Rice plants containing these loss-of-function or gain-of-function SAGs usually exhibit delayed or accelerated leaf senescence.…”

Section: Introductionmentioning

confidence: 99%

“…Rice plants containing these loss-of-function or gain-of-function SAGs usually exhibit delayed or accelerated leaf senescence. Moreover, environmental factors including nutrient status, light quality and length, climate change, water usage, and biotic stress separately or collaboratively modulate leaf senescence (Lee and Masclaux-Daubresse, 2021).…”

Section: Introductionmentioning

confidence: 99%

OsWRKY53 Promotes Abscisic Acid Accumulation to Accelerate Leaf Senescence and Inhibit Seed Germination by Downregulating Abscisic Acid Catabolic Genes in Rice

Xie

Wang

et al. 2022

Front. Plant Sci.

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Abscisic acid (ABA) largely promotes leaf senescence and inhibits seed germination in plants. Endogenous ABA content is finely tuned by many transcription factors. In this study, we showed that OsWRKY53 is a positive regulator of leaf senescence and a negative regulator of seed germination in rice. OsWRKY53 expression was induced in leaves under aging, dark, and ABA treatment. The OsWRKY53-overexpressing (OsWRKY53-oe) plants showed early yellowing leaves, while the OsWRKY53 (oswrky53) knockout mutants maintained green leaves than the wild type under natural, dark-induced, and ABA-induced senescence conditions. Transcriptional analysis revealed that ABA catabolic genes, namely, OsABA8ox1 and OsABA8ox2, two key genes participating in ABA catabolism harboring ABA 8′-hydroxylase activity, were markedly downregulated in OsWRKY53-oe leaves. Chromatin immunoprecipitation and protoplast transient assays revealed that OsWRKY53 directly bound to the promoters of OsABA8ox1 and OsABA8ox2 to repress their transcription, resulting in elevated endogenous ABA contents that promoted premature leaf senescence in the OsWRKY53-oe plants. It indicates that OsWRKY53 is a positive regulator through regulating ABA accumulation to promote leaf senescence. In addition, accumulated ABA simultaneously inhibited seed germination and post-germination growth in OsWRKY53-oe plants. Taken together, OsWRKY53 suppresses the transcript of ABA catabolic genes to promote ABA accumulation to modulate ABA-induced leaf senescence and ABA-mediated inhibition of seed germination.

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Current Understanding of Leaf Senescence in Rice

Cited by 65 publications

References 146 publications

Super Rice With High Sink Activities Has Superior Adaptability to Low Filling Stage Temperature

Super Rice With High Sink Activities Has Superior Adaptability to Low Filling Stage Temperature

Mathematical Modeling Reveals That Sucrose Regulates Leaf Senescence via Dynamic Sugar Signaling Pathways

OsWRKY53 Promotes Abscisic Acid Accumulation to Accelerate Leaf Senescence and Inhibit Seed Germination by Downregulating Abscisic Acid Catabolic Genes in Rice

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