Genetic Diversity and Genome Wide Association Study of β-Glucan Content in Tetraploid Wheat Grains

PLoS One. 2016 Apr 5;11(4):e0152590. doi: 10.1371/journal.pone.0152590. eCollection 2016.

Abstract

Non-starch polysaccharides (NSPs) have many health benefits, including immunomodulatory activity, lowering serum cholesterol, a faecal bulking effect, enhanced absorption of certain minerals, prebiotic effects and the amelioration of type II diabetes. The principal components of the NSP in cereal grains are (1,3;1,4)-β-glucans and arabinoxylans. Although (1,3;1,4)-β-glucan (hereafter called β-glucan) is not the most representative component of wheat cell walls, it is one of the most important types of soluble fibre in terms of its proven beneficial effects on human health. In the present work we explored the genetic variability of β-glucan content in grains from a tetraploid wheat collection that had been genotyped with a 90k-iSelect array, and combined this data to carry out an association analysis. The β-glucan content, expressed as a percentage w/w of grain dry weight, ranged from 0.18% to 0.89% across the collection. Our analysis identified seven genomic regions associated with β-glucan, located on chromosomes 1A, 2A (two), 2B, 5B and 7A (two), confirming the quantitative nature of this trait. Analysis of marker trait associations (MTAs) in syntenic regions of several grass species revealed putative candidate genes that might influence β-glucan levels in the endosperm, possibly via their participation in carbon partitioning. These include the glycosyl hydrolases endo-β-(1,4)-glucanase (cellulase), β-amylase, (1,4)-β-xylan endohydrolase, xylanase inhibitor protein I, isoamylase and the glycosyl transferase starch synthase II.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Genetic Variation*
  • Genome-Wide Association Study
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism
  • Seeds / genetics*
  • Seeds / metabolism
  • Tetraploidy*
  • Triticum / genetics*
  • Triticum / metabolism
  • beta-Glucans*

Substances

  • Plant Proteins
  • beta-Glucans

Grant support

The research project was supported by grants from Ministero dell’Istruzione, dell’Università e della Ricerca, project ‘PON-01_01145 ISCOCEM’. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.