Identification And Expression Analysis Of Response Regulators In Fragaria Vesca

Strawberry(Fragaria × ananassa Duch),which belongs to Rosaceae(Fragaria)and perennial herb,is originated in South America.Strawberry is widely cultivated worldwide and consistents with consumer's preference due to its high nutritive value and healthcare function.Fragaria vesca can be used as a model plant for cultivated strawberry and orther Rosaceae plants because it is a diploid with a sequenced genome and it is easy to cultivate and breed.Response regulators are important components of the two component signal system,which is involved in the regulation of plant growth and development,and in the response to cytokinin,stresses,etc.Therefore,growth,development and stress tolerance of plants can be regulated by fine-tuning of the gene expression of response regulators according to their identification and functional analysis.Fragaria vesca Hawaii 4 was used in this study for the identification of response regulators with bioinformatics methods.The tissue specific expressions and stress/ABA responses of response regulator genes were detected and analyzed,which laid foundation for future functional analysis of response regulators in strawberry.The main results were shown as follows:1.The conserved domain sequences of all response regulators from Arabidopsis were used as queries to search against the strawberry database to find out all possible response regulators in strawberry.Then Pfam search was preformed for domain identification.The phylogenetic tree of response regulators from Fragaria vesca and Arabidopsis was constructed.Cis-elements in promoter regions and exon-intron distributions of response regulators were analyzed.A total of 18 response regulators were identified in Fragaria vesca.They were further classified into three types:type A(FvRR 1-7),type B(FvRR8-14)and type C(FvRR15-17)according to the domain architecture and the phylogeny.Moreover,the phylogenetic tree demonstrated that most response regulators of Fragaria vesca and Arabidopsis formed clear orthologous pairs,indicating conserved evolution of the response regulators in these two species.Therefore,the functions of response regulators in Fragaria vesca could be predicted based on the functions of response regulators in Arabidopsis.2.Roots,stems,stolon,leaves,flowers,young fruits and ripe fruits were selected at the reproductive stage of the Fragaria vesca plants.The expression patterns of response regulators in various tissues and organs were detected by RT-PCR.The results showed that most type A and type B response regulators were mainly expressed in vegetative tissues while type C response regulators were mainly expressed in reproductive organs.According to the RT-PCR results,FvRR1,2 and 3 in type A response regulators showed relatively high expressions while FvRR7 in type A,FvRR12,14 in type B and FvRR16,17 in type C response regulators showed relatively low expressions.3.High temperature,high salt,dehydration and ABA treatments were performed at seedling stage of Fragaria vesca.The response patterns of response regulators were tested in roots and leaves by RT-PCR.The results showed that the expressions of most response regulators were decreased under various treatments.Some response regulators showed the same response pattern to one treatment or several treatments done in this experiment,which indicated that functional redundancy existed in different response regulators.In constrast,some other response regulators showed different responses to different treatments,which indicated that they had different regulatory effects under various streees.In addition,the responses of response regulators in roots and leaves did not always show the same pattern under a same treatment.