Validation by isolation and expression analyses of the mitogen-activated protein kinase gene family in the grapevine (Vitis vinifera L.)

Background and Aims Mitogen-activated protein kinases have been found to play essential roles in mediating biotic and abiotic stress responses in plants. Investigation of their possible involvement in grapevine resistance to biotic or abiotic stresses and of their development will be possible only through future functional genomics experiments of gain/loss of function in the grapevine. Methods and Results We identified and re-annotated all 12 mitogen-activated protein kinases genes from the 12X V1 sequenced grapevine genome and re-nominated them according to international standards as VvMPK. All were validated by cloning their cDNA sequences through polymerase chain reaction amplification. Expression analysis of VvMPK genes using microarray analysis and quantitative real-time polymerase chain reaction demonstrated that all VvMPK genes are expressed during grapevine growth and development. Based on expression analysis of grapevine tissues and organs at several developmental stages, and of leaf tissues treated with Erysiphe necator (powdery mildew), salicylic acid, ethylene, hydrogen peroxide and drought, we identified for further functional characterisation several VvMPK candidate genes which might be involved in grapevine growth and development and in biotic and abiotic responses. Conclusions We identified several grapevine MPK genes modulated at the transcriptional level in several stages of grapevine growth and development and during the response to development and environmental stresses. Significance of the Study This is the first comprehensive experimental survey of the grapevine MPK gene family, which provides insights into their potential roles in regulating responses to biotic and abiotic stresses. Ongoing functional characterisation of important candidate VvMPK genes will assist unravelling their biological roles in grapevine.