Abstract
Bryophytes live throughout the world from the tropics to Antarctica. Many mosses can grow in extreme environment such as lands with dry and cold seasons. The moss Physcomitrella patens acquires high freezing tolerance (FT) upon treatment with abscisic acid (ABA) and survives after cryopreservation. We demonstrated that ABA induced morphological changes in cellular organelles and accumulation of boiling-stable proteins and soluble sugars. The increase in FT was strongly inhibited by cycloheximide suggesting critical roles of synthesis of nuclear encoded protein in ABA-induced FT.
To identify genes involved in development of FT of P. patens, we carried out differential screening. Results of analysis of more than 60 isolated clones indicated that a large proportion of the ABA-induced genes had similarity to higher plant stress-induced genes such as those encoding LEA and aquaporin, whereas several other genes encoded proteins not conserved in higher plants such as LI818 and UVI-1.
