Characterization of self-incompatibility and expression profiles of CsMCU2 related to pollination in different varieties of tea plants

Abstract Tea plant is confronted with several limitations, such as self-incompatibility, which poses a great challenge to tea breeding. In this study, this physiological response and molecular insights of incompatibility reaction in self-pollinated and cross-pollinated pistils of tea plant were analyzed to explore the factors involved in incompatible reaction. Aniline blue staining analysis revealed no significant difference in pollen germination, and pollen tubes reached the base of the style at 48 h after self- and cross-pollination, thus, ovary is a critical location involving incompatible reaction. Transcribe data of self- and reciprocal cross-pollinated pistils showed that CsMCU2 (mitochondrial calcium uniporter protein 2 in C. sinensis) may be a gene related to incompatible process of tea plants. Gene expression profiles showed that the expression levels of CsMCU2 were tissue-specific, and may be related to incompatible reaction in tea plants. The patterns of variability of endogenous hormones contents in styles and ovaries varied with type of pollination and tea plant, indicating that incompatible reactions may have different regulatory mechanism in tea plants. This study provides reference for further study on incompatible response in tea plants.