Abstract:

Transgenic citrange lines with rolABC genes behave resset branching and extreme dwarfing. To explore the regulatory mechanism of plant hormones in axillary shoot growth of transgenic citrange，a full length cDNA of CPMAX2 was cloned from citrange[Citrus sinensis（L.）Osb × Poncirus trifoliate（L.）Raf.] by RT-PCR in this study. The expression of CPMAX2 was detected in axillary tender leaves of 3 transgenic citrange lines and the wild type；Additionally，we constructed an over-expression vector CPMAX2-pCAMBIA1301 for further study. The results showed that the cDNA sequence and its putative peptide sequence shared 99.66% and 99.14% of identity with its citrus sinensis ortholog MAX2. The deduced amino acid sequence contained putatively one F-box and two LRR repeat domains that arehighly conserved in MAX2 genes. CPMAX2 was obviously down-expressed in tender leaves of 3 transgenic citrange lines compared with the wild type. The results suggest CPMAX2 play an important role in regulating the rosette shoot growth in transgenic citrange with rolABC genes.

Key words: citrus, strigolactone, CPMAX2 gene, axillary bud outgrowth