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Epigenetic Mutation of RAV6 Affects Leaf Angle and Seed Size in Rice.

Epigenetic Mutation of RAV6 Affects Leaf Angle and Seed Size in Rice.

Authors :
Xiangqian Zhang
Jing Sun
Xiaofeng Cao
Xianwei Song
Source :
Plant Physiology. Nov2015, Vol. 169 Issue 3, p2118-2128. 17p.
Publication Year :
2015

Abstract

Heritable epigenetic variants of genes, termed epialleles, can broaden genetic and phenotypic diversity in eukaryotes. Epialleles may also provide a new source of beneficial traits for crop breeding, but very few epialleles related to agricultural traits have been identified in crops. Here, we identified Epi-rav6, a gain-of-function epiallele of rice (Oryza sativa) RELATED TO ABSCISIC ACID INSENSITIVE3 (ABI3)/VIVIPAROUS1 (VP1) 6 (RAV6), which encodes a B3 DNA-binding domain-containing protein. The Epi-rav6 plants show larger lamina inclination and smaller grain size; these agronomically important phenotypes are inherited in a semidominant manner. We did not find nucleotide sequence variation of RAV6. Instead, we found hypomethylation in the promoter region of RAV6, which caused ectopic expression of RAV6 in Epi-rav6 plants. Bisulfite analysis revealed that cytosine methylation of four CG and two CNG loci within a continuous 96-bp region plays essential roles in regulating RAV6 expression; this region contains a conserved miniature inverted repeat transposable element transposon insertion in cultivated rice genomes. Overexpression of RAV6 in the wild type phenocopied the Epi-rav6 phenotype. The brassinosteroid (BR) receptor BR INSENSITIVE1 and BR biosynthetic genes EBISL1 DWARF, DWARF11, and BR-DEFICIENT DWARF1 were ectopically expressed in Epi-rav6 plants. Also, treatment with a BR biosynthesis inhibitor restored the leaf angle defects of Epi-rav6 plants. This indicates that RAV6 affects rice leaf angle by modulating BR homeostasis and demonstrates an essential regulatory role of epigenetic modification on a key gene controlling important agricultural traits. Thus, our work identifies a unique rice epiallele, which may represent a common phenomenon in complex crop genomes. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00320889
Volume :
169
Issue :
3
Database :
Academic Search Index
Journal :
Plant Physiology
Publication Type :
Academic Journal
Accession number :
110840397
Full Text :
https://doi.org/10.1104/pp.15.00836