Abstract:
Based on the gene sequence identified from the rubber tree (Hevea brasiliensis) genome, an 849 bp cDNA containing an ORF of 798 bp was isolated from the leaf tissue by using the RTPCR technique. The gene denoted HbLhcb21 was predicted to encode 265 amino acids with a theoretical molecular weight of 2866 kD and isolectric point of 542; the protein was promised to be a thylakoid protein of chloroplast; the protein contains one conserved lightharvesting chlorophyll a/b binding protein domain, three transmembrane helices and two Cterminal helices, a trimerization motif, several chlorophyll and carotenoid binding sites, which could be grouped into the LHCB2 subfamily based on the evolutionary relationship. Homologous analysis showed that HbLhcb21 shared an identity of about 95% with the homologs in Ricinus communis, Gossypium hirsutum, Vitis vinifera, Fragaria vesca or Theobroma cacao, suggesting a highly conserved evolution. Expression analysis indicated that HbLhcb21 was mainly expressed in the leaves, with a gradual increase as along with the leaf maturity, but a sharp decrease in senescing leaves.