Cloning and functional analysis of five TERMINAL FLOWER 1/CENTRORADIALIS‐like genes from Hevea brasiliensis

Five TERMINAL FLOWER 1 (TFL1)/CENTRORADIALIS (CEN)‐like genes were isolated and characterized from rubber tree (Hevea brasiliensis). All genes, except HbCEN1, were found to have conserved genomic organization, characteristic of the phosphatidyl ethanolamine‐binding protein (PEBP) family. Overexpression of all of them delayed flowering and altered flower architecture compared with the wild‐type (wt) counterpart. In addition, as premature‐flowering of the terminal bud was successfully overcome in the tfl1‐1 mutant of Arabidopsis, all these genes have a potential function similar to TFL1. Quantitative reverse transcriptase‐polymerase chain reaction analysis showed higher expressions of HbCEN1 and HbCEN2 in the shoot apices and stems of both immature and mature rubber trees than in reproductive organs. HbTFL1‐1 and HbTFL1‐2 expression was confined to roots of 3‐month‐old seedlings and HbTFL1‐3 was significantly higher in the shoot apices of these seedlings. These results suggested that HbCEN1 and HbCEN2 could be associated with the development of vegetative growth, whereas HbTFL1‐1, HbTFL1‐2 and HbTFL1‐3 seem to be mainly related with maintenance of juvenility. In addition, four of the five genes displayed variable diurnal expression, HbTFL1‐1 and HbTFL1‐3 being mainly expressed during the night whereas HbCEN1 and HbCEN2 showed irregular diurnal rhythms.