Two translationally controlled tumor protein (TCTP) genes from Hevea brasiliensis play overlapping and different roles in development and stress response

Translationally controlled tumor protein (TCFP) is a highly conserved protein and performs vital roles in regulating general growth and development in eukaryotes. Rubber tree (Hevea brasiliensis) harbors two TCTP genes, HbTCTP and HbTCTP1, but the individual functions of them were unknown in plant. Here, sequence analysis displayed that HbTCTP and HbTCTP1 had the same number of 5'-terminal oligopyrimidine tract (5'-TOP) motifs in the 5'-untranslated region (UTR). However, the number of AUUUA motifs in the 3'-UTR was different between two TCTPs. HbTCTP and HbTCTP1 indicated different expression profiles in phloem and its exudate under ethylene treatment, suggesting that functional divergence likely occurred between two TCTPs in rubber tree. Moreover, HbTCTP and HbTCTPl had different effect on adventitious shoot differentiation from leaf explants during transformation. Overexpressing HbTCTP or HbTCTP1 in tobacco enhanced the tolerance to H2O2-mediated oxidative stress and alleviated cell death induced by tunicamycin, suggesting that HbTCTP and HbTCTP1 played overlapping roles in the oxidative stress resistance and anti-apoptosis. Our results provide important insights into function and characteristics of HbTCTP and HbTCTP1.