EXPANSINS IN CHERRY: EXPRESSION OF EXPANSIN PROTEINS IN CHERRIES AND DETECTION OF EXPANSIN PROMOTER ACTIVITY USING AGROINJECTION

Abstract

While climacteric fruits soften as a consequence of ethylene production that initiates the transcription of genes controlling cell wall modification, non-climacteric fruits seem to have a different softening mechanism. Cherries and sour cherries are non-climacteric, and expansins were suggested to be involved in their softening. Expansins are a class of proteins thought to weaken non-covalent bonds between hemicelluloses and cellulose microfibrills. In this study cell wall proteins isolated from cherries, were separated on one-dimensional and two-dimensional SDS PAGE gels. Expression characteristics of the expansin proteins were detected using polyclonal tomato expansin antibody. Four expansin isoforms were detected in cherries one with an isoelectric point close to 7 and three of them with higher isoelectric points, around 9-10. An expansin promoter was cloned from sour cherries and fused upstream region of GUS reporter gene. Reporter gene constructs were introduced into the cherries using agroinjection and GUS expression was detected by histochemical staining. Results have shown that expansin promoter fragments are active and have the ability to drive transgene expression in cherries.