甘蓝型油菜独脚金内酯相关基因的克隆与表达分析

Molecular Cloning and Expression Analysis of Strigolactones-related Genes in Brassica napus L.

摘要:

独脚金内酯(strigolactones, SLs)是一类新鉴定的植物激素，参与抑制茎分枝，促进根际寄生、共生互作。采用同源克隆技术自甘蓝型油菜中得到了三个SLs相关基因，分别命名为BnMAX4, BnMAX1和BnD14，其CDS各长1707, 1593, 804bp，各编码568, 530, 267个氨基酸，推测编码的蛋白质功能分别为β-类胡萝卜素加氧酶，细胞色素P450，α/β水解酶。RT-qPCR表达分析显示在野生型甘蓝型油菜二叶及四叶一心期的各组织器官中，BnMAX4主要在二叶一心期的根中表达；BnMAX1无明显表达优势组织；BnD14在二叶一心期的叶中高表达。旱胁迫及盐胁迫处理时BnMAX4的表达趋势为骤降；BnMAX1旱胁迫处理时表达量降低，盐胁迫处理时先下降后上升，9Hr后又下降；BnD14旱胁迫处理时在3Hr与12Hr各有两个表达高点，盐胁迫处理时在3Hr表达量最高。综上所述，在甘蓝型油菜中BnMAX4与BnD14基因的表达具有一定组织特异性，三个SLs相关基因与甘蓝型油菜的干旱及盐胁迫响应有关。

Abstract:

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.