Functionally redundant SHI family genes regulate Arabidopsis gynoecium development in a dose-dependent manner

• Published in: The Plant journal : for cell and molecular biology Vol. 47; no. 1; pp. 99 - 111
• Main Authors: Kuusk, Sandra, Sohlberg, Joel J, Magnus Eklund, D, Sundberg, Eva
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01-07-2006; Blackwell Publishing Ltd; Blackwell Science
• Subjects: Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis - ultrastructure; Arabidopsis Proteins - genetics; Arabidopsis Proteins - physiology; Arabidopsis thaliana; Biological and medical sciences; Botany; Chemical agents; Flowers & plants; Flowers - growth & development; Flowers - ultrastructure; Fundamental and applied biological sciences. Psychology; gene duplication; Gene expression; gene family; gene redundancy; Genes; Genotype & phenotype; gynoecium; leaf; leaf development; Multigene Family - physiology; mutants; Mutation; Phenotype; Plant physiology and development; proteins; Recombinant Fusion Proteins; style; Transcription Factors - genetics; Transcription Factors - physiology; Two-Hybrid System Techniques; Vegetative apparatus, growth and morphogenesis. Senescence; Yeasts - genetics; zinc finger motif; gene redundancy; Stamen; Plant leaf; Phylogeny; leaf; Gynoecium; Arabidopsis thaliana; Gene; gene family; Cruciferae; Dicotyledones; Angiospermae; Development; Spermatophyta; style; Mutation
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/j.1365-313x.2006.02774.x

Gene duplication events, and the subsequent functional divergence of duplicates, are believed to be important evolutionary agents, driving morphological diversification. We have studied the structural and functional diversification of members of a plant-specific gene family in Arabidopsis thaliana by analysing mutant phenotypes, expression patterns and phylogeny. The SHI gene family comprises ten members that encode proteins with a RING finger-like zinc finger motif. We show that, despite being highly divergent in sequence, except in two conserved regions, many of the SHI-related genes are partially redundant in function and synergistically promote gynoecium, stamen and leaf development in Arabidopsis. Gynoecia of the loss-of-function sty1-1 mutant display subtle morphological defects, and, although mutations in the related STY2, SHI, SRS3, SRS4, SRS5, SRS7 and LRP1 genes have no apparent effect on gynoecium development, the sty1-1 mutant phenotype is gradually enhanced in double, triple, quadruple and quintuple mutant combinations, suggesting a remarkably extensive functional conservation within the family, which appears to be based on dosage dependency and protection against dominant negative mutations. In multiple mutant lines, all marginal tissues in the apical part of the gynoecium are dramatically reduced or missing, and our data indicate that SHI family members may promote formation of these tissues downstream of the transcriptional co-repressor LEUNIG (LUG).