巴西橡胶树SnRK1家族基因的克隆与表达分析

Cloning and Expression Analysis of SnRK1 Genes in Hevea brasiliensis

蔗糖非酵解型蛋白激酶I(Sn RK1)是植物糖信号途径的关键因子,广泛参与植物生长发育。以蓖麻Sn RK1基因序列为探针,采用同源克隆的方法获得了橡胶树Sn RK1家族2个基因的全长c DNA,分别命名为Hb Sn RK1-1(KX237690.1)和Hb Sn RK1-2(KX237691.1)。2个Hb Sn RK1基因均编码含515个氨基酸且序列高度一致(96.5%)的蛋白质;2个基因均含10个外显子、9个内含子,且外显子大小相近,但基因长度差异明显。在6种橡胶树组织中,2个Hb Sn RK1基因均有表达,但Hb Sn RK1-1在胶乳(产胶细胞乳管的细胞质)中的表达量明显高于Hb Sn RK1-2;在叶片发育不同时期,Hb Sn RK1-1的表达变化不显著,而Hb Sn RK1-2的表达随叶片发育明显下降;在胶乳中,Hb Sn RK1-1的表达显著受乙烯和茉莉酸诱导、受2,4-D抑制,但Hb Sn RK1-2表达受激素处理的影响较小,推测Hb Sn RK1可能参与胶乳再生的激素调控。

In higher plants, sucrose non-fermenting 1-related protein kinase 1 （SnRK1） plays a critical role in sugar signaling in relation to growth and development. Here, the full-length cDNAs of two SnRK1 genes were cloned from rubber tree （H. brasiliensis） by homology cloning using a homolog of castor oil plants as the query sequence. The two SnRK1 genes were named as HbSnRKI-1 （KX237690.1） and HbSnRK1-2 （KX237691.1）, respectively. Both HbSnRK1 genes predicted a protein of 515 amino acids, and shared a sequence identity of 96.5%. Both HbSnRK1 genes contained 10 exons and 9 introns, but exhibited a large difference in genomic size. Real-time PCR was conducted to characterize the expression patterns of the two HbSnRK1 genes. HbSnRK1-1 and HbSnRK1-2 expressions were detected in all the six Hevea tissues examined, but in the latex （cytoplasm of rubber-producing laticifers）, HbSnRKI-1 was much higher expressed than HbSnRK1-2. During the development of Hevea leaves, HbSnRK1-1 expressions showed little change, whereas HbSnRK1-2 expressions decreased progressively. In the latex, the expression of HbSnRKI-1 was significantly stimulated by the treatments of ethylene and jasmonic acid, but repressed by the treatment of 2,4-D. In comparison, the expression of HbSnRK1-2 was much less affected by all the 7 hormones examined. These results suggest HbSnRK1 was involved in hormone-regulated latex regeneration in H. brasiliensis.