Mutational analysis of chilling tolerance in plants

Abstract

ABSTRACTA mutational approach was taken to identify genes required for low‐temperature growth of the chilling‐tolerant plant Arabidopsis thaliana. The screen identified mutants that were specifically compromised in their ability to grow at 5°C but were indistinguishable from wild type when grown at 22°C. The populations screened were mutated either by ethyl methanesulphonate or by T‐DNA insertion. In both cases symptoms at 5°C included chlorosis, reduced growth, necrosis and death. This diversity of phenotypes demonstrates roles for chilling‐tolerance responses in such diverse processes as organdie biogenesis, cell metabolism and cell and organ development. Co‐segregation analysis on the first five mutants isolated from the T‐DNA lines indicated that in three of them, pfc1, pfc2 and sop1, the chilling phenotype is the result of T‐DNA insertion in a gene required for chilling tolerance rather than the creation of a temperature‐conditional mutation in an essential housekeeping gene. This identification of T‐DNA tagged alleles will facilitate cloning of the PFC1, PFC2 and SOP1 loci and allow for the biochemical and molecular genetic characterization of these chilling‐tolerance genes and the proteins that they encode.