scholarly journals Leaf-derived ABA regulates rice seed development via a transporter-mediated and temperature-sensitive mechanism

2021 ◽  
Vol 7 (3) ◽  
pp. eabc8873
Author(s):  
Peng Qin ◽  
Guohua Zhang ◽  
Binhua Hu ◽  
Jie Wu ◽  
Weilan Chen ◽  
...  
Keyword(s):  
Seed Development ◽  
Starch Synthesis ◽  
Biological Significance ◽  
Grain Filling ◽  
Temperature Sensitive ◽  
Rice Seed ◽  
Dependent Manner ◽  
Long Distance ◽  
Long Distance Transport ◽  
Mechanistic Basis

Long-distance transport of the phytohormone abscisic acid (ABA) has been studied for ~50 years, yet its mechanistic basis and biological significance remain very poorly understood. Here, we show that leaf-derived ABA controls rice seed development in a temperature-dependent manner and is regulated by defective grain-filling 1 (DG1), a multidrug and toxic compound extrusion transporter that effluxes ABA at nodes and rachilla. Specifically, ABA is biosynthesized in both WT and dg1 leaves, but only WT caryopses accumulate leaf-derived ABA. Our demonstration that leaf-derived ABA activates starch synthesis genes explains the incompletely filled and floury seed phenotypes in dg1. Both the DG1-mediated long-distance ABA transport efficiency and grain-filling phenotypes are temperature sensitive. Moreover, we extended these mechanistic insights to other cereals by observing similar grain-filling defects in a maize DG1 ortholog mutant. Our study demonstrates that rice uses a leaf-to-caryopsis ABA transport–based mechanism to ensure normal seed development in response to variable temperatures.

scholarly journals Changes in the Elemental and Metabolite Profile of Wheat Phloem Sap during Grain Filling Indicate a Dynamic between Plant Maturity and Time of Day

Metabolites ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 53 ◽  
Author(s):  
Lachlan Palmer ◽  
James Stangoulis
Keyword(s):  
Metal Ions ◽  
Grain Filling ◽  
Metabolite Profile ◽  
Time Of Day ◽  
Wheat Breeding ◽  
Phloem Exudate ◽  
Long Distance ◽  
Phloem Sap ◽  
Long Distance Transport ◽  
Distance Transport

The long distance transport of Fe and Zn in the phloem sap of wheat (Triticum aestivum L.) is the key route for seed supply, due to wheat having a xylem discontinuity. To date, our knowledge is limited on Fe and Zn homeostasis in the phloem sap during the reproductive and grain filling stages. With the use of aphid stylectomy to collect samples of phloem sap, we explored maturity and morning versus afternoon (within-day) changes in nutrient and metabolite profiles. Phloem exudate was collected from a wheat breeding line, SAMNYT16, at three times during the grain filling period and at both midday and mid-afternoon. There were significant changes in the concentration of Mg, K, Fe and Zn during the course of grain loading and there were also significant within-day differences for Fe and K concentrations in the phloem exudate during the early phases of grain development. We found that, for K and Fe, there was an increase of 1.1- and 1.4-fold, respectively, for samples taken prior to midday to those from mid-afternoon. There was also a significant decrease in K, Fe and Zn phloem sap concentration of 1.5-, 1.4- and 1.1-fold, respectively, from the start of peak grain loading to the end of grain loading. Of the 79 metabolites detected within samples of phloem exudate, 43 had significant maturity differences and 38 had significant within-day variability. Glutamine was found to increase by 3.3–5.9-fold from midday to mid-afternoon and citric acid was found to decrease by 1.6-fold from the start of grain loading to the end of grain loading. These two metabolites are of interest as they can complex metal ions and may play a role in long distance transport of metal ions. The work presented here gives further insight into the complex composition of the phloem sap and variability that can occur during the day and also with increasing maturity.

scholarly journals SDG711 Is Involved in Rice Seed Development through Regulation of Starch Metabolism Gene Expression in Coordination with Other Histone Modifications

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Xiaoyun Liu ◽  
Junling Luo ◽  
Tiantian Li ◽  
Huilan Yang ◽  
Ping Wang ◽  
...  
Keyword(s):  
Seed Development ◽  
Starch Synthesis ◽  
Endosperm Development ◽  
Starch Accumulation ◽  
Body Region ◽  
Rice Seed ◽  
Normal Seed ◽  
Gene Body Region ◽  
Metabolism Gene

AbstractSDG711 is a histone H3K27me2/3 transmethylase in rice, a homolog of CLF in Arabidopsis, and plays key roles in regulating flowering time and panicle development. In this work, we investigated the role of SDG711 in rice seed development. Overexpression and downregulation of SDG711 lead to a decrease and increase in the expression level of genes related to starch accumulation, resulting in smaller seeds or even seed abortion. ChIP assay showed that SDG711-mediated H3K27me3 changed significantly in genes related to endosperm development, and SDG711 can directly bind to the gene body region of several starch synthesis genes and amylase genes. In addition, H3K4me3 and H3K9ac modifications also cooperate with H3K27me3 to regulate the development of the endosperm. Our results suggest that the crosstalk between SDG711-mediated H3K27me3 and H3K4me3, and H3K9ac are involved in starch accumulation to control normal seed development.

scholarly journals Effects of OsCDPK1 on the Structure and Physicochemical Properties of Starch in Developing Rice Seeds

2018 ◽  
Author(s):  
Jian-Zhi Jiang ◽  
Chun-Hsiang Kuo ◽  
Bo-Hong Chen ◽  
Mao-Kei Chen ◽  
Choun-Sea Lin ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Seed Development ◽  
Functional Role ◽  
Molecular Mechanisms ◽  
Amylose Content ◽  
Grain Filling ◽  
Rice Seed ◽  
Starch Granules ◽  
Double Stranded Rna ◽  
Filling Phase

Overexpression of a constitutively active truncated form of OsCDPK1 (OEtr) in rice produced smaller seeds, but a double-stranded RNA gene-silenced form of OsCDPK1 (Ri) yielded large seeds, suggesting that OsCDPK1 plays a functional role in rice seed development. In the study presented here, we propose a model in which OsCDPK1 plays key roles in negatively controlling the grain size, amylose content, and endosperm appearance, and also affects the physicochemical properties of the starch. The dehulled transgenic OEtr grains were smaller than the dehulled wild-type grains, and the OEtr endosperm was opaque and had a low amylose content and numerous small loosely packed polyhedral starch granules. However, the OEtr grain sizes and endosperm appearances were not affected by the temperature being either optimal (25 °C ) or low (22 °C) or high (31 °C) during the grain-filling phase. In contrast, the transgenic Ri grains were larger, had higher amylose contents, and had more transparent endosperms filled with tightly packed polyhedral starch granules. This demonstrates that OsCDPK1 plays a novel functional role in starch biosynthesis during seed development and affects the transparent appearance of the endosperm. These results improve our understanding of the molecular mechanisms through which the grain filling process occurs in rice.

scholarly journals Effects of OsCDPK1 on the Structure and Physicochemical Properties of Starch in Developing Rice Seeds

2018 ◽  
Vol 19 (10) ◽  
pp. 3247 ◽  
Author(s):  
Jian-Zhi Jiang ◽  
Chun-Hsiang Kuo ◽  
Bo-Hong Chen ◽  
Mao-Kei Chen ◽  
Choun-Sea Lin ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Seed Development ◽  
Functional Role ◽  
Molecular Mechanisms ◽  
Amylose Content ◽  
Grain Filling ◽  
Rice Seed ◽  
Starch Granules ◽  
Double Stranded Rna ◽  
Filling Phase

Overexpression of a constitutively active truncated form of OsCDPK1 (OEtr) in rice produced smaller seeds, but a double-stranded RNA gene-silenced form of OsCDPK1 (Ri) yielded larger seeds, suggesting that OsCDPK1 plays a functional role in rice seed development. In the study presented here, we propose a model in which OsCDPK1 plays key roles in negatively controlling the grain size, amylose content, and endosperm appearance, and also affects the physicochemical properties of the starch. The dehulled transgenic OEtr grains were smaller than the dehulled wild-type grains, and the OEtr endosperm was opaque and had a low amylose content and numerous small loosely packed polyhedral starch granules. However, the OEtr grain sizes and endosperm appearances were not affected by temperature, which ranged from low (22 °C) to high (31 °C) during the grain-filling phase. In contrast, the transgenic Ri grains were larger, had higher amylose content, and had more transparent endosperms filled with tightly packed polyhedral starch granules. This demonstrates that OsCDPK1 plays a novel functional role in starch biosynthesis during seed development and affects the transparent appearance of the endosperm. These results improve our understanding of the molecular mechanisms through which the grain-filling process occurs in rice.

Current concepts for quality assured long-distance transport of temperature-sensitive red blood cell concentrates

Vox Sanguinis ◽  
2010 ◽  
Vol 99 (1) ◽  
pp. 44-53 ◽  
Author(s):  
T. Klose ◽  
H.-H. Borchert ◽  
A. Pruß ◽  
W.-K. Roth ◽  
H. R. Bohnen ◽  
...  
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Temperature Sensitive ◽  
Long Distance ◽  
Long Distance Transport ◽  
Distance Transport

scholarly journals SDG711 is Involved in Rice Seed Development Through Regulation of Starch Metabolism Gene Expression in Coordination With Other Histone Modifications

2020 ◽  
Author(s):  
Xiaoyun Liu ◽  
Junling Luo ◽  
Tiantian Li ◽  
Huilan Yang ◽  
Ping Wang ◽  
...  
Keyword(s):  
Seed Development ◽  
Starch Synthesis ◽  
Endosperm Development ◽  
Starch Accumulation ◽  
Body Region ◽  
Rice Seed ◽  
Normal Seed ◽  
Gene Body Region ◽  
Metabolism Gene

Abstract SDG711 is a histone H3K27me2/3 transmethylases in rice, homolog ofCLFin Arabidopsis, that plays key roles in regulating of flowering time and panicle development. In this work, we investigated that the role of SDG711 in rice seed development. Overexpression and down-regulation of SDG711lead to the decrease and increase of the expression level of genes related to starch accumulation, resulting in smaller seed or even seed abortion. ChIP assay showed that SDG711-mediated H3K27me3 changed significantly in genes related to endosperm development and SDG711 can directly bind to the gene body region of several starch synthesis genes and amylase genes. In addition, H3K4me3 and H3K9ac modifications also cooperate with H3K27me3 to regulate the development of endosperm. Our results suggested that the crosstalk of SDG711-mediated H3K27me3 with H3K4me3 and H3K9ac are involved in starch accumulation to control normal seed development.

The Fine Structure of Phloem Cells

1985 ◽  
Vol 43 ◽  
pp. 632-635
Author(s):  
James Cronshaw
Keyword(s):  
Structural Studies ◽  
High Concentration ◽  
Long Distance ◽  
Phloem Tissue ◽  
Sieve Elements ◽  
Long Distance Transport ◽  
P Protein ◽  
Companion Cells ◽  
Electron Microscopical ◽  
Distance Transport

Long distance transport in plants takes place in phloem tissue which has characteristic cells, the sieve elements. At maturity these cells have sieve areas in their end walls with specialized perforations. They are associated with companion cells, parenchyma cells, and in some species, with transfer cells. The protoplast of the functioning sieve element contains a high concentration of sugar, and consequently a high hydrostatic pressure, which makes it extremely difficult to fix mature sieve elements for electron microscopical observation without the formation of surge artifacts. Despite many structural studies which have attempted to prevent surge artifacts, several features of mature sieve elements, such as the distribution of P-protein and the nature of the contents of the sieve area pores, remain controversial.

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