Molecular Investigation on Expression Analysis of Tapping Panel Dryness (TPD) Syndrome Associated Genes in Rubber Tree (Hevea brasiliensis Muell.Arg.)

Abstract

Rubber clones especially high yielding clones (RRII 105, PCK2, PB 217, and GT 1) are considered to be susceptible to Tapping Panel Dryness (TPD) syndrome. The main objective of this study was to find the significance of TPD associated genes in rubber tree and their expression of mRNA transcript level by Real Time PCR and Semi-Quantitative RT-PCR. A total of 15 TPD associated candidate genes were screened by RT-real time PCR. Among these, 8 candidate genes were analysed by Semi-Quantitative RT-PCR. RT-real time PCR result revealed that among 15 genes screened, mRNA transcript level of 3 genes (TOM 20, TCTP, and Myb 1) was down-regulated significantly in various TPD affected clones of rubber tree compared to healthy and their expression pattern was altered in different rubber clones due to various degrees of TPD tolerance. Semi-Quantitative RT-PCR results proved a down-regulation of five genes (TOM 20, TCTP, Myb 1, ABC, and PT2) in the TPD tree in comparison to the healthy tree. The findings of this study confirmed that the mRNA transcript levels of the TOM 20, TCTP, and Myb 1 genes were significantly lower in various rubber clones that had been affected by TPD and also suggested that these genes may be crucial for the development of TPD, which results in impaired latex biosynthesis in rubber trees.