Molecular Cloning of importin and exportin in Hevea brasiliensis and Gene Expression Induced by Ethylene

Abstract:

The aim was to understand the functions of importin and exportin genes in Hevea brasiliensis. The full-length cDNAs of importin and exportin gene were cloned from H. brasiliensis by rapid amplification of cDNA ends (RACE) technique, named as HbIMP and HbXPO, respectively. The results showed that HbIMP was 4170 bp in length, encoding 1115 amino acids, and HbXPO for 4108 bp in length, encoding 1081 amino acids. Multiple sequence alignment and phylogenetic analysis revealed that HbIMP belonged to importin5 subfamily, while HbXPO to exportin1A subfamily. The sequences analysis showed that HbIMP contained 18 exons and 17 introns, while HbXPO had 30 exons and 29 introns, and both of them containing ethylene response elements ERELEE4 and LECPLEACS2 in upstream sequences. Real time PCR analysis indicated that both HbIMP and HbXPO had expression in root, stream, leaf and bark, but not in latex, but their expression in latex were obviously induced by ethylene stimulation. Therefore, it was suggested that HbIMP and HbXPO might be involved in the transporting of macromolecules induced by ethylene.

Key words:Hevea brasiliensis;Ethylene;Importinβ family;Gene clone