Synergistic influence of sucrose and abscisic acid on the genes involved in starch synthesis in maize endosperm

The formation of meristemoids and the ontogeny of the shoot apical meristem (SAM) were studied using cultured zygotic embryos of Arabidopsis thaliana (L.) Heynh. LER ecotype. In the callus induction treatment, the procambial cells within the cotyledons of the embryo explants proliferated and gave rise to callus tissues. At the end of the treatment, a band of small cytoplasmic-rich cells derived from the procambium was produced and located at the outer surface of the callus. Upon transfer to the shoot induction medium (SIM) in the absence of abscisic acid (ABA), the cytoplasmic cells differentiated mainly into vascular elements and vacuolated parenchyma cells. This pattern of development negatively affected the explants’ ability to produce meristemoids and SAMs. Contrary to the control, the inclusion of ABA in the SIM resulted first in starch synthesis and accumulation in the surface cytoplasmic cells. This was followed by the formation of cytoplasmic cells among the starch-rich cells; further proliferation of the cytoplasmic cells resulted in the formation of meristemoids. The formation of tracheary elements was suppressed in the ABA-containing SIM. Upon transferring to the shoot development medium, which lacked plant growth regulators, some meristemoids differentiated into apical meristem cells. These cells had distinct nuclei and nucleoli, with little starch present. Additional cell divisions increased the size of the future SAM. Shoot buds with distinct SAMs were clearly delineated with the appearance of leaf primordia.

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The Importance of the Enzyme Sucrose Synthase for Cell Wall Synthesis in Plants

10.32747/1994.7568771.bard ◽

1994 ◽

Author(s):

Deborah P. Delmer ◽

Prem S. Chourey

Keyword(s):

Cell Wall ◽

Plasma Membrane ◽

Cotton Seed ◽

Sucrose Synthase ◽

Starch Synthesis ◽

Endosperm Development ◽

Current Evidence ◽

Cell Wall Synthesis ◽

Maize Endosperm ◽

Callose Deposition

The goal of this work was to understand the role of the enzyme sucrose synthase (SuSy) in synthesis of cellulose and callose in plants. The work resulting from the this grant leads to a number of conclusions. SuSy clearly plays diverse roles in carbon metabolism. It can associate with the plasma membrane of cells undergoing rapid cellulose deposition, such as cotton fibers, developing maize endosperm, gravistimulated pulvini, and transfer cells of the cotton seed. It is also concentrated at sites of high callose deposition (tapetal cells; cell plates). When SuSy levels are lowered by mutation or by anti-sense technology, cell walls undergo degeneration (maize endosperm) and show reduced levels of cellulose (potato tubers). In sum, our evidence has very much strengthened the concept that SuSy does function in the plasma membrane to channel carbon from sucrose via UDP-glucose to glucan synthase complexes. Soluble SuSy also clearly plays a role in providing carbon for starch synthesis and respiration. Surprisingly, we found that the cotton seed is one unique case where SuSy apparently does not play a role in starch synthesis. Current evidence in sum suggests that no specific SuSy gene encodes the membrane-associated form, although in maize the SS 1 form of SuSy may be most important for cell wall synthesis in the early stages of endosperm development. Work is still in progress to determine what does control membrane localization - and the current evidence we have favors a role for Ca2+, and possibly also protein phosphorylation by differentially regulated protein kinases. Finally, we have discovered for the first time, a major new family of genes that encode the catalytic subunit of the cellulose synthase of plants - a result that has been widely cited and opens many new approaches for the study of this important plant function.

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Coordinated regulation of starch synthesis in maize endosperm by microRNAs and DNA methylation

The Plant Journal ◽

10.1111/tpj.15043 ◽

2020 ◽

Author(s):

Yufeng Hu ◽

Yangping Li ◽

Jianfeng Weng ◽

Hanmei Liu ◽

Guowu Yu ◽

...

Keyword(s):

Dna Methylation ◽

Starch Synthesis ◽

Maize Endosperm ◽

Coordinated Regulation

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Inhibition of maize endosperm cell division and endoreduplication by exogenously applied abscisic acid

Physiologia Plantarum ◽

10.1034/j.1399-3054.1998.1040215.x ◽

1998 ◽

Vol 104 (2) ◽

pp. 266-272 ◽

Cited By ~ 36

Author(s):

Stefania Mambelli ◽

Tim L. Setter

Keyword(s):

Abscisic Acid ◽

Cell Division ◽

Endosperm Cell ◽

Maize Endosperm

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Maize endosperm-specific transcription factors O2 and PBF network the regulation of protein and starch synthesis

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1613721113 ◽

2016 ◽

Vol 113 (39) ◽

pp. 10842-10847 ◽

Cited By ~ 59

Author(s):

Zhiyong Zhang ◽

Xixi Zheng ◽

Jun Yang ◽

Joachim Messing ◽

Yongrui Wu

Keyword(s):

Transcription Factors ◽

Double Mutant ◽

Starch Content ◽

Starch Synthesis ◽

Starch Synthase ◽

Maize Endosperm ◽

Protein Levels ◽

Pyruvate Orthophosphate Dikinase ◽

Branching Enzymes ◽

Critical Components

The maize endosperm-specific transcription factors opaque2 (O2) and prolamine-box binding factor (PBF) regulate storage protein zein genes. We show that they also control starch synthesis. The starch content in the PbfRNAi and o2 mutants was reduced by ∼5% and 11%, respectively, compared with normal genotypes. In the double-mutant PbfRNAi;o2, starch was decreased by 25%. Transcriptome analysis reveals that >1,000 genes were affected in each of the two mutants and in the double mutant; these genes were mainly enriched in sugar and protein metabolism. Pyruvate orthophosphate dikinase 1 and 2 (PPDKs) and starch synthase III (SSIII) are critical components in the starch biosynthetic enzyme complex. The expression of PPDK1, PPDK2, and SSIII and their protein levels are further reduced in the double mutants as compared with the single mutants. When the promoters of these genes were analyzed, we found a prolamine box and an O2 box that can be additively transactivated by PBF and O2. Starch synthase IIa (SSIIa, encoding another starch synthase for amylopectin) and starch branching enzyme 1 (SBEI, encoding one of the two main starch branching enzymes) are not directly regulated by PBF and O2, but their protein levels are significantly decreased in the o2 mutant and are further decreased in the double mutant, indicating that o2 and PbfRNAi may affect the levels of some other transcription factor(s) or mRNA regulatory factor(s) that in turn would affect the transcript and protein levels of SSIIa and SBEI. These findings show that three important traits—nutritional quality, calories, and yield—are linked through the same transcription factors.

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Effect of Exogenous Gibberellin, Paclobutrazol, Abscisic Acid, and Ethrel Application on Bulblet Development in Lycoris radiata

Frontiers in Plant Science ◽

10.3389/fpls.2020.615547 ◽

2021 ◽

Vol 11 ◽

Author(s):

Junxu Xu ◽

Qingzhu Li ◽

Ye Li ◽

Liuyan Yang ◽

Yongchun Zhang ◽

...

Keyword(s):

Abscisic Acid ◽

Carbohydrate Metabolism ◽

Starch Synthesis ◽

Soluble Starch ◽

Future Research ◽

Expression Levels ◽

Metabolism Enzymes ◽

Genes Encoding ◽

Lycoris Radiata ◽

Bulblet Development

Lycoris species have great ornamental and medicinal values; however, their low regeneration efficiency significantly restricts their commercial production. Exogenous hormone application is an effective way to promote bulblet development, but their effect on Lycoris radiata has not been verified to date. In the present study, we examined the effect of different exogenous hormones on bulblet development in L. radiata, and found that gibberellic acid (GA) significantly inhibited, whereas paclobutrazol (PBZ), abscisic acid (ABA), and ethrel promoted bulblet development, especially PBZ, a GA biosynthesis inhibitor. Furthermore, GA reduced endogenous cytokinin (CK) content, as well as the activities of carbohydrate metabolism enzymes, including sucrose synthase (SUS) and glucose-1-phosphate adenylyltransferase (AGPase), by downregulating the expression levels of LrSUS1, LrSUS2, and genes encoding AGPase large and small subunits. This resulted in the decrease in carbohydrate accumulation in the bulblets, thus hindering their development. PBZ had the opposite effect to GA on carbohydrate metabolism; it decreased endogenous GA15 and GA24, thereby promoting bulblet development. ABA promoted endogenous auxin content and the activities of starch synthesis enzymes, especially soluble starch synthase (SSS) and granule-bound SS (GBSS), through the up-regulation of the expression levels of LrSS1, LrSS2, and LrGBSS1 genes, which could also result in the accumulation of carbohydrates in the bulblets and promote their development. In addition, ethrel application partly promoted bulblet development by promoting endogenous CK content. Although the accumulation of carbohydrates and the activity of starch enzymes were increased by ethrel treatment, we hypothesized that the effect of ethrel on regulating carbohydrate metabolism may be indirect. Our results could provide a basis for improving the propagation efficiency of L. radiata for production, as well as propose some directions for future research.

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