Analysis of nucleotide sequences of the ABI3 gene coding region in pea varieties with different percentage of seed storage proteins

Abstract

The main source of vegetable protein in the world are leguminous crops, among which peas are the most common in Russia. Dozens and even hundreds of genes are involved in the regulation of biological processes associated with the maturation of seeds and the accumulation of reserve nutrients in them, including proteins. The study conducted on legume species related to peas indicate that one of the genes at the highest hierarchical level in this regulatory chain is the ABI3 transcription factor gene; however, its role in the biosynthesis and accumulation of seed storage proteins remains poorly studied. The purpose of the current work is to identify high-protein pea genotypes and analyze the nucleotide sequences of the coding region of the ABI3 gene to search for possible DNA polymorphisms associated with protein percentage in their seeds. The study was carried out in 2020–2021. The objects of the study were 37 pea varieties from the collection of genetic resources of leguminous crops of VIR. Protein percentage in seeds was determined by the Bradford method. Selection of primers and comparative analysis of nucleotide sequences were performed using the PrimerSelect and MegAlign programs. Sequencing was performed according to the Sanger method. There were identified pea varieties with the highest (‘Aksaisky Usaty 55’, ‘Sakharny’) and low (‘K-8361’ (VIR), ‘Fregat’) seed protein percentage. In these variety samples, the coding region of the ABI3 gene was sequenced. Comparative analysis of their nucleotide sequences with the sequence of the ABI3 gene fragment annotated in the GenBank database revealed significant variability among them: nucleotide substitutions, deletion of 6 nucleotides. In the high protein variety ‘Sakharny’, there has been found a 9-nucleotide insertion, leading to the insertion of three additional amino acids, and in the low-protein variety Fregat, there has been found a single nucleotide insertion, causing a shift in the reading frame. The data obtained may indicate a correlation between mutations in the ABI3 gene and protein accumulation in pea seeds.