Fasciclin-like arabinogalactan protein gene expression is associated with yield of flour in the milling of wheat

Ravi C Nirmal,Agnelo Furtado,Parimalan Rangan,Robert J Henry

doi:10.1038/s41598-017-12845-y

Abstract

A large portion of the global wheat crop is milled to produce flour for use in the production of foods such as bread. Pressure to increase food supplies sustainably can be address directly by reducing post-harvest losses during processes such as flour milling. The recovery of flour in the milling of wheat is genetically determined but difficult to assess in wheat breeding due to the requirement for a large sample. Here we report the discovery that human selection for altered expression of putative cell adhesion proteins is associated with wheats that give high yields of flour on milling. Genes encoding fasciclin-like arabinogalactan proteins are expressed at low levels in high milling wheat genotypes at mid grain development. Thirty worldwide wheat genotypes were grouped into good and poor millers based flour yield obtained from laboratory scale milling of mature seeds. Differentially expressed genes were identified by comparing transcript profiles at 14 and 30 days post anthesis obtained from RNA-seq data of all the genotypes. Direct selection for genotypes with appropriate expression of these genes will greatly accelerate wheat breeding and ensure high recoveries of flour from wheat by resulting in grains that break up more easily on milling.

Highlights

Wheat is the leading crop in the temperate world[1]
14 genotypes had Pina-D1a/Pinb-D1a alleles of puroindoline genes within which 7 genotypes showed soft grain texture (SKCS HI < 50) and 7 showed hard grain texture (SKCS HI > 50), 8 genotypes were hard with Pina mutation (Pina-D1b/Pinb-D1a), and 7 were hard wheats with Pinb mutation (Pina-D1a/Pinb-D1b) (Table 1)[18]
RNA-Seq analysis of genotypes corresponding to the poor milling (PM)-group and high milling (HM)-group, followed by application of the Baggerley’s test for identification of significant differences led to the identification of twelve genes at 14 days post anthesis (DPA) and eight genes at 30 DPA that were statistically differentially expressed at a false discovery rate (FDR) p-value of

Summary

Introduction

Wheat is the leading crop in the temperate world[1]. It provides 20% of the total calories and proteins consumed worldwide[2]. Small scale laboratory test mills are widely used for the selection of wheat genotypes that deliver a higher flour yield This process is difficult because the test has poor repeatability and still requires more than 1 kg of grain. Knowledge of the molecular basis[17] of the intense human selection for high flour yield in breeding modern wheat genotypes would greatly accelerate the breeding of wheat combining high productivity and the grain quality required by consumers. This capability will be of great value in rapidly adapting wheat to changing and variable climates. RNA Seq of 30 diverse worldwide wheat genotypes was conducted at 14 and 30 days post anthesis (DPA) and gene expression was analysed relative to flour yield obtained on laboratory milling of the mature grain

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Results

Conclusion