ThMYC4E, candidate Blue aleurone 1 gene controlling the associated trait in Triticum aestivum.

Na Li,Wenjie Chen,Kunpu Zhang,Dengcai Liu,Daowen Wang,Baolong Liu,Shiming Li,Bo Zhang,Huaigang Zhang,Harsh Raman

doi:10.1371/journal.pone.0181116

Abstract

Blue aleurone is a useful and interesting trait in common wheat that was derived from related species. Here, transcriptomes of blue and white aleurone were compared for isolating Blue aleurone 1 (Ba1) transferred from Thinopyrum ponticum. In the genes involved in anthocyanin biosynthesis, only a basic helix-loop-helix (bHLH) transcription factor, ThMYC4E, had a higher transcript level in blue aleurone phenotype, and was homologous to the genes on chromosome 4 of Triticum aestivum. ThMYC4E carried the characteristic domains (bHLH-MYC_N, HLH and ACT-like) of a bHLH transcription factor, and clustered with genes regulating anthocyanin biosynthesis upon phylogenetic analysis. The over-expression of ThMYC4E regulated anthocyanin biosynthesis with the coexpression of the MYB transcription factor ZmC1 from maize. ThMYC4E existed in the genomes of the addition, substitution and near isogenic lines with the blue aleurone trait derived from Th. ponticum, and could not be detected in any germplasm of T. urartu, T. monococcum, T. turgidum, Aegilops tauschii or T. aestivum, with white aleurone. These results suggested that ThMYC4E was candidate Ba1 gene controlling the blue aleurone trait in T. aestivum genotypes carrying Th. ponticum introgression. The ThMYC4E isolation aids in better understanding the genetic mechanisms of the blue aleurone trait and in its more effective use during wheat breeding.

Highlights

Blue grain wheat cultivars have a blue aleurone layer that contains a group of anthocyanin pigments that differ from those in purple, red or white wheat grains [1,2,3]
72 genotypes with white aleurone were used to confirm the lack of ThMYC4E in T. urartu, T. monococcum, T. turgidum, Ae. tauschii or T. aestivum, and four cultivars with blue aleurone traits derived from Th. ponticum were used to verify the universality of ThMYC4E in the cultivars containing the 4E chromosome (S1 Table)
The chromosomal locations of the homologues of phenylalanine ammonia lyase (PAL), F3050H and dihydrofavonol 4-reductase (DFR) were on chromosomes 2B, 1A and 7D, respectively, while all five of the basic helix-loop-helix (bHLH) transcription factors resided on chromosome 4D (S3 Table)

Summary

Introduction

Blue grain wheat cultivars have a blue aleurone layer that contains a group of anthocyanin pigments that differ from those in purple, red or white wheat grains [1,2,3]. Because it is observed, the blue aleurone trait has been used as a genetic marker for measuring the outcrossing frequencies among wheat cultivars, detecting the distance of pollen transmission, identifying true hybrids and monitoring chromosomal changes caused by wheat. ThMYC4E, candidate Blue aleurone 1 gene in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Methods

Results

Conclusion