Abstract
The inflorescence of Arabidopsis ecotype Landsberg harboring the erecta mutation shows a corymb-like inflorescence. To understand inflorescence development, we previously screened corymb-like inflorescence mutations, named corymbosa1 (crm1). Cloning of the CRM1 gene revealed that it is allelic to BIG. CRM1/BIG is highly expressed in inflorescence meristems and floral meristems by in situ hybridization and histochemical analysis using transgenic plants. Allelic series of crm1/big mutants, reduced lateral root formation (rlr) were categorized into two classes depending on the defects of plant development. Identification of the molecular defects and Northern blotting suggest that rlr mutants whose phenotypes are changed alternately corresponding with the size of presumed CRM1/BIG protein are hypomorphic alleles. The severities of the corymbose inflorescence in crm1/rlr mutants were correlated with increased levels of PINFORMED1 gene, suggesting that CRM1/BIG controls inflorescence development through auxin transport. Further analyses of the expression pattern of several genes are now under way.
