COMPARATIVE TRANSCRIPTOME ANALYSIS REVEALS EARLY GENE EXPRESSION PROFILE THAT CONTRIBUTES TO COLD RESISTANCE IN HEVEA BRASILIENSIS (PARA RUBBER TREE)

Abstract

Rubber trees (Hevea brasiliensis) are tropical perennial woody plants that are susceptible to cold stress. In China, cold stress caused severe damages to rubber plantations in the past decades. Though several cold resistant Hevea clones have been bred, their cold hardiness mechanism is yet to be unraveled. In this study, the cold resistant clone CATAS93-114 and sensitive Reken501 were subjected to cold stress and their transcriptomes were analyzed at the time points of 0h, 2h, 8h and 24h. De novo transcriptome assembly and comparison were then carried out. The results showed that there were totally 7870 genes differentially expressed in these clones. The resistant clone CATAS93-114 had more genes being evoked from 2h to 8h during cold treatment, indicating more rapidly and intensively responsive profile than the sensitive clone Reken501. The DE genes can be further classified into seven major clusters, and GO terms in each cluster were enriched. The genes involved in ABA metabolism and signaling, ABA-independent pathway and early signal perception were noteworthy for their distinctive expression patterns toward cold stress between clones. Twenty-two genes playing a central role in these pathways were further investigated, and QPCR analysis of these genes confirmed the RNA-Seq results.

Keywords:   cold resistance, Hevea brasiliensis, transcriptome, QPCR, RNA-seq, ABA, rubber, hevea, cold stress, gene