scholarly journals The rice G protein γ subunit qPE9-1 positively regulates grain-filling process by interacting with abscisic acid and auxin

2018 ◽  
Author(s):  
Dongping Zhang ◽  
Minyan Zhang ◽  
Yong Zhou ◽  
Yuzhu Wang ◽  
Hongyingxue Chen ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Rice Genome ◽  
Grain Filling ◽  
Starch Biosynthesis ◽  
Starch Accumulation ◽  
Genetic Studies ◽  
Filling Stage ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Grain Filling Stage

The rice genome contains a single Gα (RGA1) and Gβ (RGB1) and five Gγ subunits. Recent genetic studies have shown that DEP1/qPE9-1, an atypical putative Gγ protein, is responsible for dense and erect panicles, but the biochemical and molecular mechanisms underlying control of grain size are not well understood. Here, we report that plants carrying qPE9-1 have more endosperm cells per grain than plants contain the qpe9-1 allele. The qPE9-1 line has a higher rate and longer period of starch accumulation than the qpe9-1 line. Additionally, the expression of several key genes encoding enzymes catalyzing sucrose metabolism and starch biosynthesis is higher in the qPE9-1 line than in the qpe9-1 line, especially from the mid to late grain-filling stage. Grains of the qPE9-1 line also have higher contents of two phytohormones, ABA and IAA. Exogenous application of ABA or IAA enhanced starch accumulation and the expression of genes encoding grain-filling-related enzymes in the grains of qPE9-1, whereas only IAA produced these effects in qpe9-1. Based on these results, we conclude that qPE9-1 promotes endosperm cell proliferation and positively regulates starch accumulation largely through ABA and IAA, which enhance the expression of genes encoding starch biosynthesis during the late grain-filling stage.

scholarly journals The Rice G Protein γ Subunit DEP1/qPE9–1 Positively Regulates Grain-Filling Process by Increasing Auxin and Cytokinin Content in Rice Grains

Rice ◽  
2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Dongping Zhang ◽  
Minyan Zhang ◽  
Yong Zhou ◽  
Yuzhu Wang ◽  
Jinyu Shen ◽  
...  
Keyword(s):  
Grain Size ◽  
G Protein ◽  
Molecular Mechanisms ◽  
Grain Filling ◽  
Starch Biosynthesis ◽  
Starch Accumulation ◽  
Filling Process ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
Grain Filling Stage

AbstractHeterotrimeric G protein-mediated signal transduction is one of the most important and highly conserved signaling pathways in eukaryotes, which involves in the regulation of many important biological processes. As compared with those in mammals and Arabidopsis thaliana, the functions of rice heterotrimeric G protein and their molecular mechanisms are largely unknown. The rice genome contains a single Gα (RGA1) and Gβ (RGB1), and five Gγ (RGG1, RGG2, GS3, DEP1/qPE9–1, and GGC2) subunits. Recent genetic studies have shown that DEP1/qPE9–1, an atypical putative Gγ protein, is responsible for the grain size as well as the dense and erect panicles, but the biochemical and molecular mechanisms underlying the control of grain size are not well understood. Here, we report that rice plants carrying DEP1/qPE9–1 have more endosperm cells per grain than plants contain the dep1/qpe9–1 allele. The DEP1/qPE9–1 line has a higher rate and more prolonged period of starch accumulation than the dep1/qpe9–1 line. Additionally, the expression of several essential genes encoding enzymes catalyzing sucrose metabolism and starch biosynthesis is higher in the DEP1/qPE9–1 line than in the dep1/qpe9–1 line, especially from the mid to late grain-filling stage. Grains of the DEP1/qPE9–1 line also have higher contents of three phytohormones, ABA, auxin and cytokinin. Exogenous application of auxin or cytokinin enhanced the starch accumulation and the expression of genes encoding grain-filling-related enzymes in the grains of dep1/qpe9–1, whereas ABA produced no effects. Based on these results, we conclude that DEP1/qPE9–1 positively regulates starch accumulation primarily through auxin and cytokinin, which enhance the expression of genes encoding starch biosynthesis during the mid to late grain-filling stage, resulting in increased duration of the grain-filling process.

Starch accumulation in rice grains subjected to drought during grain filling stage

2019 ◽  
Vol 142 ◽  
pp. 440-451 ◽  
Author(s):  
Prathap V ◽  
Kishwar Ali ◽  
Archana Singh ◽  
Chandrapal Vishwakarma ◽  
Veda Krishnan ◽  
...  
Keyword(s):  
Grain Filling ◽  
Starch Accumulation ◽  
Rice Grains ◽  
Filling Stage ◽  
Grain Filling Stage

scholarly journals Effects of Early- and Late-Sowing on Starch Accumulation and Associated Enzyme Activities During Grain Filling Stage in Rice

Rice Science ◽  
2021 ◽  
Vol 28 (2) ◽  
pp. 191-199
Author(s):  
Wang Wenting ◽  
Cui Wenpei ◽  
Xu Ke ◽  
Gao Hui ◽  
Wei Haiyan ◽  
...  
Keyword(s):  
Enzyme Activities ◽  
Grain Filling ◽  
Starch Accumulation ◽  
Filling Stage ◽  
Grain Filling Stage ◽  
Late Sowing

scholarly journals Activities of sucrose to starch metabolizing enzymes during grain filling in late sown wheat under water stress

2017 ◽  
Vol 9 (1) ◽  
pp. 338-343 ◽  
Author(s):  
Reena Mahla ◽  
Shashi Madan ◽  
Vikender Kaur ◽  
Renu Munjal ◽  
Rishi Kumar Behl ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Water Deficit ◽  
Starch Content ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
Starch Accumulation ◽  
Metabolizing Enzymes ◽  
Late Planting ◽  
Filling Stage ◽  
Grain Filling Stage

Tolerance to water deficit in relation to activities of sucrose-to- starch metabolizing enzymes and starch accumulation was studied in the grains of contrasting wheat (Triticum aestivum L.) genotypes (WH1021 and WH1080; tolerant) and (WH711 and HD2687; susceptible) under late planting conditions. The activities of starch metabolizing enzymes i.e. sucrose synthase (SuSase), ADP-glucose pyrophosphorylase (AGPase), soluble starch synthase (SSS) and starch branching enzymes (SBE) were substantially enhanced by water deficit in all genotypes at early to mid-grain filling stage showing peaks at 14 to 21 days after anthesis (DAA); while decreased significantly at mid-late grain filling stage with maximum decline at 35 DAA. Activities of all the enzymes under study showed maximum decline in activity (28.4–60%) in susceptible genotype WH711; whereas WH1021 proved to be most tolerant one with minimum decline in enzyme activity (14.9–32.8%). Starch content was also markedly reduced (21%) in WH711 due to drought while WH1021 reported 12% decline corresponding well with enzyme activity. A faster pre-mature cessation of starch deposition occurred in susceptible wheat genotypes compared to tolerant ones. A significant and positive correlation of the enzyme activities with starch accumulation (r = 0.491–0.555 at P0.05 for SuSase, AGPase, SSS and r = 0.638 at P0.01 for SBE) under well watered conditions indicated that enhancing the activities of the enzymes would lead to increase in starch accumulation and thus faster grain filling. Genotype WH1021 proved to be most efficient based on comparatively higher enzyme activity and least yield penalty under late planting conditions combined with water scarcity.

scholarly journals RGB1 Regulates Grain Development and Starch Accumulation Through Its Effect on OsYUC11-Mediated Auxin Biosynthesis in Rice Endosperm Cells

2021 ◽  
Vol 12 ◽  
Author(s):  
Dongping Zhang ◽  
Minyan Zhang ◽  
Jiansheng Liang
Keyword(s):  
Grain Size ◽  
G Protein ◽  
Grain Filling ◽  
Auxin Biosynthesis ◽  
Starch Accumulation ◽  
Grain Development ◽  
Filling Process ◽  
Filling Stage ◽  
Grain Filling Stage ◽  
Lower Expression

RGB1, a subunit of heterotrimeric G protein, plays important roles in regulating grain size and weight of rice. However, the molecular mechanisms underlying controlling grain filling process by G protein are still largely unclear. In the present study, we show that RGB1 controls not only the grain size but also the grain filling process. Knock-down of RGB1 significantly delayed grain development and reduced starch accumulation and grain weight, which was closely related to the delayed and the lower expression of genes encoding sucrose metabolism and starch biosynthesis related enzymes during grain filling stage. Suppression of RGB1 expression also resulted in the lower auxin content in grains, which was correlated with the lower expression of OsNF-YB1 and OsYUC11 during grain filling stage. Further biochemical evidence showed that OsYUC11 expression was under control of OsNF-YB1 by its interaction with promoter of OsYUC11. Taken together, we propose that RGB1 controls rice grain development and grain filling process by changing auxin homeostasis in endosperm cells. OsNF-YB1, which acts as a key downstream effector of RGB1, interacts directly with the promoter of OsYUC11 and stimulates the OsYUC11 expression, thereby regulating auxin biosynthesis and starch accumulation and grain size.

Effect of Temperature on Starch Accumulation and Activities of Starch Synthetic Key Enzymes during Grain-Filling Stage of Aromatic Rice

2011 ◽  
Vol 142 ◽  
pp. 152-156
Author(s):  
Zhen Jiang Xu ◽  
Li Zhong Xiao ◽  
Hong Liu ◽  
Yong Hao Ren ◽  
Zhi Lin Li
Keyword(s):  
Amylose Content ◽  
Grain Filling ◽  
Effect Of Temperature ◽  
Starch Accumulation ◽  
Aromatic Rice ◽  
Key Enzymes ◽  
Filling Stage ◽  
Lower Temperature ◽  
Grain Filling Stage ◽  
The Relationship

Changes of the content of starch, amylose and the activities of 3 key enzymes involved in starch synthetic metabolism in developing rice grains under four different temperature in phytotrons during grain filling stage of two aromatic rice varieties were studied. The results showed that compared with that under the lower temperature (21°C and 23°C), the content of starch and amylose and the activities of SBE and GBSS under higher temperatures (26°Cand 30°C) were generally higher at the beginning of the grain filling stage and obviously lower during the middle and late grain filling stage, with the exception of the activity SSS which were always higher under lower temperature. The relationship between the changes of activities of SSS, SBE and the variation of starch accumulating rate was very close and so did the relationship between GBSS activity and the amylose content. The lower activities of SSS, SBE and GBSS during the middle and late grain filling stage may be the key physiological factors which lead to the poorer progress quality and appearance quality of aromatic rice under high temperature.

Effect of Temperature during Grain Filling Stage on Endosperm Structure and Apperance Quality of Aromatic Rice

2012 ◽  
Vol 460 ◽  
pp. 286-289 ◽  
Author(s):  
Zhen Jiang Xu ◽  
Li Zhong Xiao ◽  
Hong Liu ◽  
Yong Hao Ren ◽  
Zhi Lin Li
Keyword(s):  
Grain Filling ◽  
Effect Of Temperature ◽  
Rice Grain ◽  
Aromatic Rice ◽  
Starch Granules ◽  
Filling Stage ◽  
Appearance Quality ◽  
Endosperm Structure ◽  
Grain Filling Stage

Based on the experiment of two inbred aromatic rice varieties and one hybrid aromatic rice line treated under four different temperatures( daymean temperature 21°C, 23°C, 26°C and 30°C respectively) during grain filling stage in phytotrons, the shape and arrangement of endosperm starch granules in rice grain transection were observed by scanning electron microscope and the related characteristics of rice grain qualities of chalky percent and chalkiness were analyzed at the same time. The results showed that under the lower temperature( daymean temperature21°C and 23°C), many large compound starch granules with clear angulars packed together regularly without significant natural gaps bewteen starch granules in the tansectional endosperm. However, with the increase of temperature, starch granules in the transectional endosperm were changed from regularly shaped and closely and orderly arranged to various shaped and chaoticly arranged with obvious natural gaps between starch granules, which was closely consistent with the poorer appearance quality under the higher temperature, which indicated that the endosperm structure is closely related with appearance quality of aromatic rice.

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