EcoTILLING Reveals Natural Allelic Variations in Starch Synthesis Key Gene TaSSIV and Its Haplotypes Associated with Higher Thousand Grain Weight.

Irshad Irshad,Xiong Xiong,Ding Ding,Guo Guo,Xie Xie,Liu Liu,Zhao Zhao,Zhang Zhang,Ma Ma,Gu Gu

doi:10.3390/genes10040307

Irshad Irshad, Xiong Xiong + Show 8 more

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https://doi.org/10.3390/genes10040307

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Abstract

Wheat is a staple food commodity grown worldwide, and wheat starch is a valuable source of energy and carbon that constitutes 80% of the grain weight. Manipulation of genes involved in starch synthesis significantly affects wheat grain weight and yield. TaSSIV plays an important role in starch synthesis and its main function is granule formation. To mine and stack more favorable alleles, single nucleotide polymorphisms (SNPs) of TaSSIV-A, B, and D were investigated across 362 wheat accessions by Ecotype-Targeting Induced Local Lesions IN Genome (EcoTILLING). As a result, a total of 38 SNPs in the amplified regions of three TaSSIV genes were identified, of which 10, 15, and 13 were in TaSSIV-A, B, and D, respectively. These 38 SNPs were evaluated by using KASP and six SNPs showed an allele frequency >5% whereas the rest were <5%, i.e., considered to be minor alleles. In the Chinese mini core collection, three haplotypes were detected for TaSSIV–A and three for TaSSIV–B. The results of an association study in the Chinese mini core collection with thousand grain weight (TGW) and spike length (SPL) showed that Hap-2-1A was significantly associated with TGW and Hap-3-1B with SPL. Allelic frequency and geographic distribution indicated that the favored haplotype (Hap-2-1A) has been positively selected in Chinese wheat breeding. These results suggested that the Kompetitive Allele Specific PCR (KASP) markers can be applied in starch improvement to ultimately improve wheat yield by marker assisted selection in wheat breeding.

Highlights

Breeding for yield potential of cereal crops due to a surging population is an important priority.Wheat is a staple food commodity for the ever-growing worldwide population
This panel mainly consisted of 262 mini core collection (MCC) accessions from China and 100 accessions originating from Pakistan (Table S1)
Gene structure analysis showed that TaSSIV-A consisted of 13 exons and 12 introns while TaSSIV-B, and TaSSIV-D each consisted of 16 exons and 15 introns

Summary

Introduction

Breeding for yield potential of cereal crops due to a surging population is an important priority. Wheat is a staple food commodity for the ever-growing worldwide population. Wheat is central to food security and has a large share of required calories globally. Starch is a valuable source of carbon and energy. Starch is synthesized during daytime from photosynthetically-fixed carbon and is mobilized in the night time. It is synthesized in other transient organs such as root cap cells and meristems, but major storage organs are fruits, tubers, seeds, and roots [1]. At the physiological level, seed crop yields are mainly determined by source and sink relationships [2]

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