Identification of Two GLOBOSA-Like MADS-Box Genes in Tea Plant (Camellia sinensis [L.] O. Kuntze)

Abstract

Tea plant (Camellia sinensis [L.] O. Kuntze) is a woody crop of high economic importance worldwide; however, information on the molecular mechanisms underlying the regulation of flower development in this species is limited. In the present study, two GLOBOSA (GLO)-like MADS-box genes, CsGLO1 and CsGLO2, were isolated from C. sinensis ‘Ziyangzhong’ and were characterized to elucidate their roles in flower development. We found that CsGLO1 and CsGLO2 are nuclear-localized transcription factors without transactivation ability but with a robust interaction. They have similar patterns of expression, both mainly restricted to petals and stamens. Moreover, ectopic expression of either CsGLO1 or CsGLO2 in Arabidopsis thaliana resulted in a partial conversion of sepals to petals, suggesting full GLOBOSA functional activity. Our results indicate that CsGLO1 and CsGLO2 paralogs might redundantly contribute to petal and stamen, providing the first insight into their role in tea plant flower development.