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Role of the gibberellin receptors GID 1 during fruit‐set in Arabidopsis
Author(s) -
GallegoGiraldo Carolina,
Hu Jianhong,
Urbez Cristina,
Gomez Maria Dolores,
Sun Taiping,
PerezAmador Miguel A.
Publication year - 2014
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12603
Subject(s) - gibberellin , biology , arabidopsis , mutant , ovule , gynoecium , receptor , microbiology and biotechnology , gene , phenotype , repressor , genetics , botany , gene expression , embryo , stamen , pollen
Summary Gibberellins ( GA s) play a critical role in fruit‐set and fruit growth. Gibberellin is perceived by its nuclear receptors GA INSENSITIVE DWARF 1s ( GID 1s), which then trigger degradation of downstream repressors DELLA s. To understand the role of the three GA receptor genes ( GID 1A , GID 1B and GID 1C ) in Arabidopsis during fruit initiation, we have examined their temporal and spatial localization, in combination with analysis of mutant phenotypes. Distinct expression patterns are revealed for each GID 1: GID 1A is expressed throughout the whole pistil, while GID 1B is expressed in ovules, and GID 1C is expressed in valves. Functional study of gid1 mutant combinations confirms that GID 1A plays a major role during fruit‐set and growth, whereas GID 1B and GID 1C have specific roles in seed development and pod elongation, respectively. Therefore, in ovules, GA perception is mediated by GID 1A and GID 1B, while GID 1A and GID 1C are involved in GA perception in valves. To identify tissue‐specific interactions between GID 1s and DELLA s, we analyzed spatial expression patterns of four DELLA genes that have a role in fruit initiation ( GAI , RGA , RGL 1 and RGL 2 ). Our data suggest that GID 1A can interact with RGA and GAI in all tissues, whereas GID 1C– RGL 1 and GID 1B– RGL 2 interactions only occur in valves and ovules, respectively. These results uncover specific functions of each GID 1– DELLA in the different GA ‐dependent processes that occur upon fruit‐set. In addition, the distribution of GA receptors in valves along with lack of expression of GA biosynthesis genes in this tissue, strongly suggests transport of GA s from the developing seeds to promote fruit growth.