The General Transcription Repressor TaDr1 Is Co-expressed With TaVrn1 and TaFT1 in Bread Wheat Under Drought.

Lyudmila Zotova,Sergey Sereda,Peter Langridge,Vladimir Shvidchenko,Carly Schramm,Sergiy Lopato,Nazgul Shamambayeva,Colin Jenkins,Azamat Kashapov,Kathleen Soole,Nikolay P Goncharov,Satyvaldy Jatayev,Akhylbek Kurishbayev,Yuri Shavrukov,Ainur Otemissova,Arystan Nuralov

doi:10.3389/fgene.2019.00063

Abstract

The general transcription repressor, TaDr1 gene, was identified during screening of a wheat SNP database using the Amplifluor-like SNP marker KATU-W62. Together with two genes described earlier, TaDr1A and TaDr1B, they represent a set of three homeologous genes in the wheat genome. Under drought, the total expression profiles of all three genes varied between different bread wheat cultivars. Plants of four high-yielding cultivars exposed to drought showed a 2.0–2.4-fold increase in TaDr1 expression compared to controls. Less strong, but significant 1.3–1.8-fold up-regulation of the TaDr1 transcript levels was observed in four low-yielding cultivars. TaVrn1 and TaFT1, which controls the transition to flowering, revealed similar profiles of expression as TaDr1. Expression levels of all three genes were in good correlation with grain yields of evaluated cultivars growing in the field under water-limited conditions. The results could indicate the involvement of all three genes in the same regulatory pathway, where the general transcription repressor TaDr1 may control expression of TaVrn1 and TaFT1 and, consequently, flowering time. The strength of these genes expression can lead to phenological changes that affect plant productivity and hence explain differences in the adaptation of the examined wheat cultivars to the dry environment of Northern and Central Kazakhstan. The Amplifluor-like SNP marker KATU-W62 used in this work can be applied to the identification of wheat cultivars differing in alleles at the TaDr1 locus and in screening hybrids.

Highlights

Amongst the many types of abiotic stresses, drought or water limitation is one of the most important challenges for native plants and crops
The aims of this work were: (1) to compare flowering time and time to grain maturity of high-yielding and low-yielding wheat cultivars from Kazakhstan; (2) to analyze the genetic polymorphism of the TaDr1 gene in eight selected bread wheat cultivars, and in an F3 segregating population 18-6 originating from a complex interspecies hybridisation; (3) to study TaDr1, TaVrn1 and TaFT1 gene expression in response to drought in leaves of selected wheat cultivars; and (4) to assess the co-expression of TaDr1, TaVrn1, and TaFT1 genes and grain yields of wheat cultivars in the dry conditions of Northern and Central Kazakhstan
Expression Analysis of the TaDr1 in Leaves of Control Plants and Plants Exposed to Drought

Summary

Introduction

Amongst the many types of abiotic stresses, drought or water limitation is one of the most important challenges for native plants and crops. Amplifluor SNP markers are well-established and have been successfully applied in the recent genotyping of candidate genes for various plant species (Absattar et al, 2018; Yerzhebayeva et al, 2018; Khassanova et al, 2019). This includes research in bread wheat, where alleles of candidate genes for drought tolerance, TaDREB5 and TaNFYC-A7, were identified using Amplifluor SNP markers. Over-expression of OsNF-YA7 increased drought tolerance in transgenic rice plants (Lee et al, 2015), and OsNF-YB1 controls grain filling, resulting in improved yield (Xu et al, 2016)

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