Project description:Tapping panel dryness (TPD) seriously affects the natural rubber (NR) production of Hevea brasiliensis (rubber tree). Several studies have speculated that TPD influences NR biosynthesis in the latex of rubber trees based on the expression changes of NR biosynthesis-related genes. In this study, iTRAQ analysis of latex were carried out to reveal the molecular mechanism of TPD affecting rubber trees NR biosynthesis activity and molecular weight.
Project description:ngs2014_07_hevea-hevea_tpd-seq-RNAseq analysis of latex samples from healthy and Tapping Panel Dryness-affected trees.-Identification of Tapping Panel Dryness (TPD)-affected trees in a polyclonal trials grown under standard condition. Trees were tapped since November 2010 every 2 days. Latex yield and TPD occurrence were monitored as well as latex RNA samples were collected twice a year for further analysis. At the end of the experiment, gene expression in latex of healthy and TPD trees were compared.
Project description:This study is committed to de novo sequencing and comparative analysis of the transcriptomes of healthy (H) and Tapping panel dryness (TPD)-affected (T) rubber trees to identify the genes and pathways related to the TPD. Total raw reads of 34,632,012 and 35,913,020 bp were obtained from H and T library, respectively using Illumina Hiseq 2000 sequencing technology. De novo assemblies yielded 141,456 and 169,285 contigs, and 96,070 and 112,243 unigenes from H and T library, respectively. Among 66535 genes, 107021 genes were identified as differential expressed genes between H and T library via comparative transcript profiling. A majority of genes involved in natural rubber biosynthesis and jasmonate synthesis with most potential relevance in TPD occurrence were found to be differentially expressed. In TPD-affected trees, the expression of most genes related to the latex biosynthesis and jasmonate synthesis was severely inhibited and it probably the direct cause of the TPD. Our de novo transcriptome data sets provide a significant resource for the discovery of genes related to TPD and improve our understanding the occurrence and maintainace of TPD.
Project description:Currently, one of the most serious threats in rubber tree is the tapping panel dryness (TPD) that greatly restricts the natural rubber production. Over tapping or ethephon stimulation is regarded as the main cause of TPD occurrence. Although extensive studies have been carried out, the molecular mechanism on the TPD still remains puzzled. In the present study, TMT proteome analysis of barks of rubber trees were performed to extend our understanding of the nature and molecular mechanism underlying TPD.
Project description:Nutural rubber (NR) production, latex is harvested by periodical tapping of the trunk bark. Ethylene enhances and prolongs latex flow and latex regeneration. Ethephon, which is an ethylene-releasing compound, applied to the trunk before tapping usually results in a 1.5- to 2-fold increase in latex yield. We investigated gene expression in response to ethephon treatment using Pará rubber tree seedlings as a model system. After ethephon treatment, 3,270 genes showed significant differences in expression compared with the mock treatment. Genes associated with carotenoids, flavonoids, and abscisic acid biosynthesis were significantly upregulated by ethephon treatment, which might contribute to an increase in latex flow. Genes associated with secondary cell wall formation were downregulated, which might be because of the reduced sugar supply. Given that sucrose is an important molecule for NR production, a trade-off may arise between NR production and cell wall formation for plant growth and for wound healing at the tapping panel.
