A Novel Arabidopsis Thaliana Mutation Causes Defects in Cellular Development. (Biology Section).

Jilk, R., and L. Huntington. Department of Biology, Rockhurst University. A NOVEL ARABIDOPSIS THALIANA MUTATION CAUSES DEFECTS IN CELLULAR DEVELOPMENT. A mutant strain of Arabidopsis thaliana was created by T-DNA insertional mutagenesis. The characterization of this mutation shows a recessive mutation with several apparently unrelated phenotypes. This mutation was originally isolated for the fact that the trichomes do not show the branching patterns seen in wild type strains, earning the mutant allele the name SINGLE TRICHOME VARIANT 1. Scanning electron microscopy of the developing leaves also shows incompletely differentiated epidermal pavement cells. The mutation also leads to a high degree of lethality, where 90% of plants wilt and die within two days of being transferred to soil. Studies done to determine optimal growth conditions demonstrate that the mutant plants are highly sensitive to microbial infection, and do best when raised in sterile conditions. Even so, the surviving plants leave only sterile seeds. The site of the T-DNA insertion has been mapped and sequenced to a region of chromosome 5 with no previously reported function. The results of the characterization of the mutation indicate that the affected protein plays a key role in proper cellular differentiation and morphogenesis.