天然橡胶生物合成相关基因表达与橡胶产量的相关性

胶乳被认为是橡胶树的一种与伤害应答相关联的保护物质。割胶可以显著促进橡胶生物合成,且此促进作用与激活乳管细胞中橡胶生物合成相关基因的表达相关,但相关性大小尚不清楚。本文通过qPCR分析了正常割胶条件下,6个橡胶生物合成相关基因HbHRT2、HbSRPP、HbREF、HbHMGR1、HbHRT1、HbGAPDH在5个橡胶树魏克汉种质和5个1981°IRRDB种质胶乳中的表达情况。结果显示：这6个基因在魏克汉种质中的表达水平显著高于1981°IRRDB种质,分别是后者的1.05~14.62、0.97~4.26、1.46~12.56、0.83~2.99、0.43~7.54、1.92~11.31倍,平均值是后者的7.54、2.55、5.69、1.71、2.71、4.91倍。相关性分析表明,这些基因的表达与橡胶树干胶产量呈正相关,其中,HbREF和HbGAPDH的表达水平与干胶产量之间的相关性最高,有望作为橡胶树产量育种的分子指标。

Correlation Between the Expression Level of Natural Rubber Biosynthesis Genes and Rubber Yield

Latex is thought to be a protective substance associated with injury response in rubber trees. Tapping can significantly promote rubber production, which should be closely related to the expression of genes involved in rubber biosynthesis in the laticifer cells of rubber trees. However, the exact relationship between the expression of the rubber biosynthesis genes and the dry rubber yield is yet to be elucidated. In the present study, qPCR was used to analyze the expression of six rubber biosynthesis genes, HbHRT2, HbSRPP, HbREF, HbHMGR1, HbHRT1 and HbGAPDH, in the laticifer cells of five Wichham germplasms and five 1981°IRRDB germplasms following tapping them with S/2 d/3 tapping system. The results showed that the expression of these genes was significantly higher in most Wichham germplasms than in 1981°IRRDB germplasms, as shown by fold increases of 1.05-14.62, 0.97-4.26, 1.46-12.56, 0.83-2.99, 0.43-7.54, 1.92-11.31, respectively, for HbHRT2, HbSRPP, HbREF, HbHMGR1, HbHRT1 and HbGAPDH. Correspondingly, the average fold change was 7.54, 2.55, 5.69, 1.71, 2.71, 4.91. Correlation analysis showed that the expression level of these genes was positively related to dry rubber yield. Two of the genes, HbREF and HbGAPDH, could be exploited as the molecular markers in high rubber yield breeding programs for both genes showed a highest correlation between their expression level and the corresponding rubber yield.