Strigolactones(SLs) constitute the recently discovered group of plant hormones, they participate in inhibiting shoot branching and promoting parasitic and symbiotic interactions in the rhizosphere. Three SLs-related genes were obtained from Brassica napus by homologous cloning, named BnMAX4, BnMAX1, BnD14; the length of CDS was 1707, 1593, 804 bp; encoding 568, 530, 267 amino acids; the putative protein function was β-carotenoid oxygenase, cytochrome P450, α/β hydrolase, respectively. Using roots, stems and leaves of wild type B. napus at two-euphylla one-bud and four-euphylla one-bud stage, expression of the three genes was analyzed by RT-qPCR, the results showed that BnMAX4 mainly expressed in the roots at two-euphylla stage; BnMAX1 didn’t show expression advantage; BnD14 significantly expressed in leaves at two-euphylla stage. Then expression of the three genes was analyzed under the drought and salt stress, the expression of BnMAX4 suddenly decreased under both stress conditions. The expression of BnMAX1 decreased under drought stress; under salt stress the expression decreased first and increased afterwards, after 9Hr decreased again. The expression of BnD14 showed two high peaks at 3Hr and 12Hr under drought stress; under salt stess the expression showed one high peak at 3Hr. Those studies have shown that the expression of BnMAX4 and BnD14 had certain tissue-specificity, and the three SLs-related genes involved in drought and salt stress responses of B. napus.
