Molecular Tools for Reverse Genetic Analyses in the Moss Physcomitrella patens

Abstract

The moss Physcomitrella patens is a model plant in which various genetic resources including the genome sequence have been well established. To clarify molecular action of plant totipotency, we developed molecular tools for reverse genetic analyses in P. patens. We searched P. patens genome for targeting sites of transgenes. For gain-of-function analyses, we constructed inducible expression systems, one using heat-shock promoter (HSP) and another one induced by estrogen application. Although gene knock-out (KO) in P. patens has been useful for loss-of-function analyses, it is important to avoid lethality of gene KO because the moss is haploid in most of its life cycle. Thus, we developed a conditional KO system by using Cre-loxP system, in which Cre recombinase is expressed under the control of HSP facilitating excision of the target gene flanked by loxP sites. We will discuss results and applicability of our reverse genetic tools.