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Author Beuchat J., Li S., Ragni L., Shindo C., Michael H Kohn, Christian S Hardtke
Title A hyperactive quantitative trait locus allele of Arabidopsis BRX contributes to natural variation in root growth vigor.
Abstract:
Quantitative trait loci analysis of natural Arabidopsis thaliana accessions is increasingly exploited for gene isolation. However, to date this has mostly revealed deleterious mutations. Among them, a loss-of-function allele identified the root growth regulator BREVIS RADIX (BRX). Here we present evidence that BRX and the paralogous BRX-LIKE (BRXL) genes are under selective constraint in monocotyledons as well as dicotyledons. Unexpectedly, however, whereas none of the Arabidopsis orthologs except AtBRXL1 could complement brx null mutants when expressed constitutively, nearly all monocotyledon BRXLs tested could. Thus, BRXL proteins seem to be more diversified in dicotyledons than in monocotyledons. This functional diversification was correlated with accelerated rates of sequence divergence in the N-terminal regions. Population genetic analyses of 30 haplotypes are suggestive of an adaptive role of AtBRX and AtBRXL1. In two accessions, Lc-0 and Lov-5, seven amino acids are deleted in the variable region between the highly conserved C-terminal, so-called BRX domains. Genotyping of 42 additional accessions also found this deletion in Kz-1, Pu2-7, and Ws-0. In segregating recombinant inbred lines, the Lc-0 allele (AtBRX(Lc-0)) conferred significantly enhanced root growth. Moreover, when constitutively expressed in the same regulatory context, AtBRX(Lc-0) complemented brx mutants more efficiently than an allele without deletion. The same was observed for AtBRXL1, which compared with AtBRX carries a 13 amino acid deletion that encompasses the deletion found in AtBRX(Lc-0). Thus, the AtBRX(Lc-0) allele seems to contribute to natural variation in root growth vigor and provides a rare example of an experimentally confirmed, hyperactive allelic variant.
Journal Proceedings of the National Academy of Sciences of the United States of America
Country Switzerland
Volume 107(18)
Pages 8475-80
Year 2010
PubMed ID 20404146
PubMed Central ID -
DOI 10.1073/pnas.0913207107
URL -
Relation
Gene BRXL1 BRXL2 BRXL3 BRXL4 BRXL5.P
INSD -
Strain Wild Core Collection -
Induced Mutation Lines(NIG Collection) -
Sterile Seed Strain -
Lethal Embryo
Mutantion Strain
-
Stages in Each Organ
- Muant Lines (Gene)
-
Cultivated Varieties(NIG Collection) -
Stages in Each Organ -
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