hosoba toge toge, a syndrome caused by a large chromosomal deletion associated with a T-DNA insertion in Arabidopsis

We isolated a T-DNA-tagged mutant named hosoba toge toge (hot) in which a p leiotropic phenotype was observed in both the shoot and root throughout the life cycle, The phenotype and allelism indicated that the mutant has a def ect in both the FASCIATA1 (FAS1) gene and the FT gene located on the bottom arm of chromosome 1, Analysis of the junctions between the T-DNA ends and the plant genome suggested the presence of a 75.8-kbp deletion at the inser tion site. In addition to FAS1 and FT, 13 genes were predicted to exist in the region corresponding to that deleted in hot. They include homologs of g enes for type II inositol-1,4,5-triphosphate 5-phosphatase (IP5Pase), the b eta-chain of N-acetyl-beta-glucosaminidase (NAGase), NADPH oxidoreductase o f the zeta-crystallin family, polygalacturonase, and endo-1,4-beta-glucanas e. Although most aspects of the hot phenotype can be explained by loss of F AS1 and FT functions, some novel phenotypic features which may represent as pects of a mutant phenotype due to loss-of-function of other gene(s) were o bserved. One "wild-type" ecotype and a previously reported T-DNA insertion line, neither of which has any obvious phenotypic abnormality, carry a poss ible loss-of-function mutation in the zeta-crystallin homolog and in the NA Gase beta chain homolog, respectively.