Transcriptome Analysis of Purple Pericarps in Common Wheat (Triticum aestivum L.).

Di Liu,Wenjie Chen,Baolong Liu,Shiming Li,Bo Zhang,Dengcai Liu,Huaigang Zhang,Wujun Ma

doi:10.1371/journal.pone.0155428

Di Liu, Wenjie Chen + Show 6 more

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https://doi.org/10.1371/journal.pone.0155428

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Abstract

Wheat (Triticum aestivum L.) cultivars possessing purple grain arethought to be more nutritious because of high anthocyanin contents in the pericarp. Comparative transcriptome analysis of purple (cv Gy115) and white pericarps was carried out using next-generation sequencing technology. There were 23,642 unigenes significantly differentially expressed in the purple and white pericarps, including 9945 up-regulated and 13,697 down-regulated. The differentially expressed unigenes were mainly involved in encoding components of metabolic pathways, The flavonoid biosynthesis pathway was the most represented in metabolic pathways. In the transcriptome of purple pericarp in Gy115, most structural and regulatory genes biosynthesizing anthocyanin were identified, and had higher expression levels than in white pericarp. The largestunigene of anthocyanin biosynthesis in Gy115 was longer than the reference genes, which implies that high-throughput sequencing could isolate the genes of anthocyanin biosynthesis in tissues or organs with high anthocyanin content. Based on present and previous results, three unigenes of MYB gene on chromosome 7BL and three unigenes of MYC on chromosome 2AL were predicted as candidate genes for the purple grain trait. This article was the first to provide a systematic overview comparing the transcriptomes of purple and white pericarps in common wheat, which should be very valuable for identifying the key genes for the purple pericarp trait.

Highlights

White- and red-grained bread wheat (Triticum aestivum L.) types are common, while few wheat cultivars possess either purple or blue grain
The structural and regulatory genes of anthocyanin biosynthesis should occupy an approprite proportion of expression relative to other genes in the kinds of cells that accumulate anthocyanins
The relative expression of anthocyanin biosynthesis genes should be relatively constant compared with all genes in these organs, meaning that the same content of RNA should contain an appreciable content of structural genes

Summary

Introduction

White- and red-grained bread wheat (Triticum aestivum L.) types are common, while few wheat cultivars possess either purple or blue grain. Purple and blue grains are thought to result from accumulation of anthocyanin in pericarp or aleurone[1,2]. Because of the high anthocyanin content, this kind of wheat is thought to be more nourishing than red or white wheat[3]. The purple or blue grain could be used as a marker for special purpose wheat to distinguish them from others, for instance in an indirect selection program to measure the degree of PLOS ONE | DOI:10.1371/journal.pone.0155428. Transcriptome Analysis in Common Wheat and analysis, decision to publish, or preparation of the manuscript The purple or blue grain could be used as a marker for special purpose wheat to distinguish them from others, for instance in an indirect selection program to measure the degree of PLOS ONE | DOI:10.1371/journal.pone.0155428 May 12, 2016

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