Differential gene expression analysis of self-incompatible lines in tea by cDNA-AFLP

Self-incompatibility (SI) is an important genetically-controlled mechanism to prevent self-fertilization. In this study, the tea cultivars 'Longjing Changye' (self-incompatible) and 'Fuding Dabaicha' were used as plant materials in four experimental groups: 1) 'Longjing Changye' without pollination, (2) 'Longjing Changye' with self-pollination, (3) 'Longjing Changye' (female) crossed with 'Fuding Dabaicha' (male), and (4) leaves of 'Longjing Changye' as a control. Genes with differentially expressed transcripts were analyzed by cDNA-AFLP. 25 differentially expressed genes that may be related to self-incompatibility were found in 'Longjing Changye' after self-pollination. These genes are involved in energy metabolism, signal transduction, programmed cell death (PCD), protein synthesis, transcription, and other processes. The expression patterns of genes encoding G-protein, a microtubule protein, and inositol phosphatase were verified by qRT-PCR in the four groups. The expression profiles suggested that G-protein and inositol phosphate were involved in the regulation of Ca(2+) concentrations in SI signal transduction, and microtubules played a role in pollen tube development in SI; these genes may be closely related to self-incompatibility.