Targeting the B1 Gene and Analysis of Its Polymorphism Associated with Awned/Awnless Trait in Russian Germplasm Collections of Common Wheat.

Diana D. Kuvaeva,Olga P. Mitrofanova,Elena A. Salina,Svetlana E. Khverenets,Alexander I. Pryanishnikov,Andrey B. Shcherban

doi:10.3390/plants10112285

Diana D. Kuvaeva, Olga P. Mitrofanova + Show 4 more

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https://doi.org/10.3390/plants10112285

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Abstract

The presence of awns on the ear is associated with a number of important plant properties, such as drought resistance, quality of the grain mass during processing, etc. The main manifestations of this trait are controlled by the B1 gene, which has recently been identified and encodes the C2H2 zinc finger transcription factor. Based on the previously identified SNPs in the promoter region of this gene, we constructed markers for dominant and recessive alleles which determine awnless and awned phenotypes, respectively. The markers were successful for use in targeting the respective alleles of the B1 gene in 176 varieties of common wheat, accessions of T. spelta L., as well as on F2/F3 hybrids from crosses between awned and awnless forms of T. aestivum. We first identified a new allele, b1mite, which has both an insert of a miniature Stowaway-like transposon, 261 bp in length, and 33 novel SNPs in the promoter region. Despite these changes, this allele had no effect on the awned phenotype. The possible mechanisms of the influence of the analyzed gene on phenotype are discussed.

Highlights

Earlier fine mapping of the B1 locus identified a single gene that can control awn length. It belongs to the transcription factor (TF) family encoding the zinc finger C2H2 domain [19,20,21]
The analysis of the promoter region was only carried out in the awnless cultivar Saratovskaya 29, and it was compared to a similar sequence from the cultivar CS, which carries the recessive allele b1 [17]
Based on the previous studies of the C2H2Zf gene (B1 gene) and our structural analysis of this gene in Russian common wheat cultivars, we first developed specific combinations of primers that effectively discriminate between recessive and dominant B1 alleles in both homo- and heterozygous states. This has been convincingly demonstrated across a variety of plant materials, including various varieties of spring and winter bread wheat, inter-varietal hybrids of different generations, as well as T. spelta specimens from different growing regions. These combinations of primers can be used in markeroriented selection based on the awned trait, as well as other important associated traits, which are subject to the pleiotropic action of the locus under study

Summary

Introduction

Intensive selection aimed at increasing yields in various climatic conditions has led to the creation of a large phenotypic diversity of cultivated wheat in terms of traits such as the shape, length, color and hairiness of the ear, awned and awnless, the number of spikelets, grain size, color and shape, etc. One of the important economically valuable traits is the presence of awns on the ear. Ear awns effectively increase inflorescence transpiration and play an important role in the processes of photosynthesis and plant respiration [1,2]. About half of the total number of stomata on a spike of wheat are located on the awns [3]. The total surface of the awns captures about 9% of visible solar radiation and increases the efficiency of photosynthesis by

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