2020 journal article

Sequence-based mapping identifies a candidate transcription repressor underlying awn suppression at the B1 locus in wheat

NEW PHYTOLOGIST, 225(1), 326–339.

By: N. DeWitt n, M. Guedira n, E. Lauer n, M. Sarinelli n, P. Tyagi n, D. Fu*, Q. Hao*, J. Murphy n ...

co-author countries: United States of America 🇺🇸
author keywords: awns; B1 locus; fine mapping; positional cloning; wheat (Triticum aestivum); zinc finger protein
MeSH headings : Amino Acid Sequence; Base Sequence; Chromosome Mapping; Chromosome Segregation / genetics; Gene Deletion; Gene Expression Regulation, Plant; Genes, Plant; Genetic Association Studies; Genetic Loci; Genetic Markers; Genome-Wide Association Study; Haplotypes / genetics; Inbreeding; Organ Size; Plant Proteins / chemistry; Plant Proteins / genetics; Quantitative Trait Loci / genetics; Recombination, Genetic / genetics; Repressor Proteins / metabolism; Suppression, Genetic; Transcription, Genetic; Triticum / anatomy & histology; Triticum / genetics; Up-Regulation / genetics
Source: Web Of Science
Added: October 14, 2019

Summary Awns are stiff, hair‐like structures which grow from the lemmas of wheat ( Triticum aestivum ) and other grasses that contribute to photosynthesis and play a role in seed dispersal. Variation in awn length in domesticated wheat is controlled primarily by three major genes, most commonly the dominant awn suppressor Tipped1 ( B1 ). This study identifies a transcription repressor responsible for awn inhibition at the B1 locus. Association mapping was combined with analysis in biparental populations to delimit B1 to a distal region of 5 AL colocalized with QTL for number of spikelets per spike, kernel weight, kernel length, and test weight. Fine‐mapping located B1 to a region containing only two predicted genes, including C2H2 zinc finger transcriptional repressor Traes CS 5A02G542800 upregulated in developing spikes of awnless individuals. Deletions encompassing this candidate gene were present in awned mutants of an awnless wheat. Sequence polymorphisms in the B1 coding region were not observed in diverse wheat germplasm whereas a nearby polymorphism was highly predictive of awn suppression. Transcriptional repression by B1 is the major determinant of awn suppression in global wheat germplasm. It is associated with increased number of spikelets per spike and decreased kernel size.