Over-Expressing <i>TaSPA-B</i> Reduces Prolamin and Starch Accumulation in Wheat (<i>Triticum aestivum</i> L.) Grains

Over-Expressing <i>TaSPA-B</i> Reduces Prolamin and Starch Accumulation in Wheat (<i>Triticum aestivum</i> L.) Grains

Starch and prolamin composition and content are important indexes for determining the processing and nutritional quality of wheat (<i>Triticum aestivum</i> L.) grains. Several transcription factors (TFs) regulate gene expression during starch and protein biosynthesis in wheat. Storage pr...

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Bibliographic Details
Main Authors: Dandan Guo, Qiling Hou, Runqi Zhang, Hongyao Lou, Yinghui Li, Yufeng Zhang, Mingshan You, Chaojie Xie, Rongqi Liang, Baoyun Li
Format: Article
Language:English
Published: MDPI AG 2020-05-01
Series:International Journal of Molecular Sciences
Subjects:
<i>Triticum aestivum</i> L.
<i>TaSPA</i>
transcriptome sequencing
prolamin
starch
wheat grains
Online Access:https://www.mdpi.com/1422-0067/21/9/3257
Description
Summary:Starch and prolamin composition and content are important indexes for determining the processing and nutritional quality of wheat (<i>Triticum aestivum</i> L.) grains. Several transcription factors (TFs) regulate gene expression during starch and protein biosynthesis in wheat. Storage protein activator (TaSPA), a member of the basic leucine zipper (bZIP) family, has been reported to activate glutenin genes and is correlated to starch synthesis related genes. In this study, we generated <i>TaSPA-B</i> overexpressing (OE) transgenic wheat lines. Compared with wild-type (WT) plants, the starch content was slightly reduced and starch granules exhibited a more polarized distribution in the <i>TaSPA-B</i> OE lines. Moreover, glutenin and ω- gliadin contents were significantly reduced, with lower expression levels of related genes (e.g., <i>By15</i>, <i>Dx2,</i> and ω-1,2 gliadin gene). RNA-seq analysis identified 2023 differentially expressed genes (DEGs). The low expression of some DEGs (e.g., <i>SUSase</i>, <i>ADPase</i>, <i>Pho1</i>, <i>Waxy</i>, <i>SBE</i>, <i>SSI</i>, and <i>SS II a</i>) might explain the reduction of starch contents. Some TFs involved in glutenin and starch synthesis might be regulated by <i>TaSPA-B,</i> for example, <i>TaPBF</i> was reduced in <i>TaSPA-B</i> OE-3 lines. In addition, dual-luciferase reporter assay indicated that both TaSPA-B and TaPBF could transactivate the promoter of ω-1,2 gliadin gene. These results suggest that <i>TaSPA-B</i> regulates a complex gene network and plays an important role in starch and protein biosynthesis in wheat.
ISSN:1661-6596
1422-0067

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