Genome-wide identification and expression analysis of the phosphatase 2A family in rubber tree (Hevea brasiliensis)

The protein phosphatase 2As (PP2As) play a key role in manipulating protein phosphorylation. Although a number of proteins in the latex of laticifers are phosphorylated during latex regeneration in rubber tree, information about the PP2A family is limited. In the present study, 36 members of the HbPP2A family were genome-wide identified. They were clustered into five subgroups: the subgroup HbPP2AA (4), HbPP2AB' (14), HbPP2AB'' (6), HbPP2AB55 (4), and HbPP2AC (8). The members within the same subgroup shared highly conserved gene structures and protein motifs. Most of HbPP2As possessed ethylene- and wounding-responsive cis-acting elements. The transcripts of 29 genes could be detected in latex by using published high-throughput sequencing data. Of the 29 genes, seventeen genes were significantly down-regulated while HbPP2AA1-1 and HbPP2AB55α/Bα-1were up-regulated by tapping. Of the 17 genes, 14 genes were further significantly down-regulated by ethrel application. The down-regulated expression of a large number of HbPP2As may attribute to the enhanced phosphorylation of the proteins in latex from the tapped trees and the trees treated with ethrel application.