A novel methyl transferase induced by osmotic stress in the facultative halophyte Mesembryanthemum crystallinum.

摘要: Abstract Molecular mechanisms of osmotic stress tolerance were studied in Mesembryanthemum crystallinum (ice plant), a facultative halophyte capable adjusting to and surviving highly saline conditions. We screened subtracted cDNA library enriched for salt stress-induced mRNAs identify transcripts involved this plant's adaptation salinity. One mRNA, Imt1, was found be up-regulated leaves and, transiently, roots. Nuclear run-on assays indicated that mRNA is transcriptionally regulated. Imt1 encoded predicted polypeptide M(r) 40,250 which exhibited sequence similarity several hydroxymethyl transferases. Expression the protein Escherichia coli subsequent activity identified as novel myoinositol O-methyl transferase catalyzes first step biosynthesis cyclic sugar alcohol pinitol. Pinitol accumulates salt-stressed M.crystallinum abundant number salt- drought-tolerant plants. The presence high levels alcohols correlates with osmotolerance diverse range organisms, including bacteria, fungi algae, well higher stress-initiated transcriptional induction IMT1 expression provides strong support importance establishing