Screening of Induced Mutants Led to the Identification of Starch Biosynthetic Genes Associated with Improved Resistant Starch in Wheat

Ahsan Irshad; Huijun Guo; Shoaib Ur Rehman; Jiayu Gu; Chaojie Wang; Hongchun Xiong; Yongdun Xie; Shirong Zhao; Luxiang Liu

doi:10.3390/ijms231810741

Screening of Induced Mutants Led to the Identification of Starch Biosynthetic Genes Associated with Improved Resistant Starch in Wheat

Int J Mol Sci. 2022 Sep 15;23(18):10741. doi: 10.3390/ijms231810741.

Authors

Ahsan Irshad¹, Huijun Guo¹, Shoaib Ur Rehman², Jiayu Gu¹, Chaojie Wang¹, Hongchun Xiong¹, Yongdun Xie¹, Shirong Zhao¹, Luxiang Liu¹

Affiliations

¹ National Engineering Laboratory of Crop Molecular Breeding, National Center of Space Mutagenesis for Crop Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
² Institute of Plant Breeding and Biotechnology, Muhammad Nawaz Sharif University of Agriculture, Multan 66000, Pakistan.

Abstract

Several health benefits are obtained from resistant starch, also known as healthy starch. Enhancing resistant starch with genetic modification has huge commercial importance. The variation of resistant starch content is narrow in wheat, in relation to which limited improvement has been attained. Hence, there is a need to produce a wheat population that has a wide range of variations in resistant starch content. In the present study, stable mutants were screened that showed significant variation in the resistant starch content. A megazyme kit was used for measuring the resistant starch content, digestible starch, and total starch. The analysis of variance showed a significant difference in the mutant population for resistant starch. Furthermore, four diverse mutant lines for resistant starch content were used to study the quantitative expression patterns of 21 starch metabolic pathway genes; and to evaluate the candidate genes for resistant starch biosynthesis. The expression pattern of 21 starch metabolic pathway genes in two diverse mutant lines showed a higher expression of key genes regulating resistant starch biosynthesis (GBSSI and their isoforms) in the high resistant starch mutant lines, in comparison to the parent variety (J411). The expression of SBEs genes was higher in the low resistant starch mutants. The other three candidate genes showed overexpression (BMY, Pho1, Pho2) and four had reduced (SSIII, SBEI, SBEIII, ISA3) expression in high resistant starch mutants. The overexpression of AMY and ISA1 in the high resistant starch mutant line JE0146 may be due to missense mutations in these genes. Similarly, there was a stop_gained mutation for PHO2; it also showed overexpression. In addition, the gene expression analysis of 21 starch metabolizing genes in four different mutants (low and high resistant starch mutants) shows that in addition to the important genes, several other genes (phosphorylase, isoamylases) may be involved and contribute to the biosynthesis of resistant starch. There is a need to do further study about these new genes, which are responsible for the fluctuation of resistant starch in the mutants.

Keywords: expression analysis; mutant population; resistant starch; wheat.

MeSH terms

Gene Expression Regulation, Plant
Phosphorylases / metabolism
Plant Proteins / genetics
Plant Proteins / metabolism
Resistant Starch
Starch* / metabolism
Triticum* / genetics
Triticum* / metabolism

Substances

Plant Proteins
Resistant Starch
Starch
Phosphorylases

Grants and funding

The work is Supported by China Agriculture Research System CARS-03 and the Agricultural Science and Technology Innovation Program (grant No. CAAS-ZDRW202002).