CAT activity and related gene expression in the pistil of self- and cross-pollinated Camellia oleifera Abel.

Camellia oleifera Abel. shows late-acting self-incompatibility (LSI) characteristics,which seriously hinder parental selection and cultivar arrangement during cross breeding. To study the role of catalase (CAT) in the self-incompatibility of C. oleifera, CAT activities in the pistils after self- and cross-pollination were determined. Three CAT genes (CoCAT1, CoCAT2, and CoCAT3) were cloned by reverse-transcription polymerase chain reaction (RT-PCR), with coding sequences (CDSs)of 1479, 1287, and 1479 bp, encoding 492, 428, and 492 amino acids, respectively. Multiple sequence alignment showed that their coding products contained typical tripeptide sequences at the C-terminal.Phylogenetic analysis showed that CoCAT2 and CoCAT3 were most closely related to NtCAT3, and CoCAT1 was most closely related to CsCAT1. Expression pattern analysis indicated that the expression levels of the three genes were highest in the self-pollinated pistils 72 h after pollination, and expression levels in the self-pollinated pistils at 36 and 84 h were significantly higher than those in the cross-pollinated pistils.Thus, self-pollination and cross-pollination increased CAT activity in the pistils of C. oleifera, but at different magnitudes. This study indicated that CAT maybe involved in the response mechanism of self-incompatibility in C. oleifera.