Abstract
Plants' S-like RNases are usually expressed in response to exogenic factors such as inorganic phosphate starvation, wounding and pathogen attack. We investigated the expression and DNA methylation profiles of carnivorous plants' S-like RNase genes using various tissues from Drosera adelae (a sundew), Dionaea muscipula (Venus flytrap) and Cephalotus follicularis. We found that in D. adelae the S-like RNase gene is expressed only in glandular tentacles and not in the other tissues. Also found was that its promoter was hypermethylated in leaves, while unmethylated in glandular tentacles. The S-like RNase gene of D. muscipula was suggested to be constitutively expressed in all tissues examined. Its promoter was revealed to be unmethylated in them. And, it was clarified that the expression of the S-like RNase gene of C. follicularis is restricted in its trap leaves while its promoter is unmethylated in all tissues. The style of carnivory seems related to the mechanism of S-like RNase gene expression. The evolution of S-like RNase genes and their expression in carnivorous plants will be discussed.
