Transcriptome and gene expression analysis in cold-acclimated guayule (Parthenium argentatum) rubber-producing tissue

Abstract

Natural rubber biosynthesis in guayule (Parthenium argentatum Gray) is associated with moderately cold night temperatures. To begin to dissect the molecular events triggered by cold temperatures that govern rubber synthesis induction in guayule, the transcriptome of bark tissue, where rubber is produced, was investigated. A total of 11,748 quality expressed sequence tags (ESTs) were obtained. The vast majority of ESTs encoded proteins that are similar to stress-related proteins, whereas those encoding rubber biosynthesis-related proteins comprised just over one percent of the ESTs. Sequence information derived from the ESTs was used to design primers for quantitative analysis of the expression of genes that encode selected enzymes and proteins with potential impact on rubber biosynthesis in field-grown guayule plants, including 3-hydroxy-3-methylglutaryl-CoA synthase, 3-hydroxy-3-methylglutaryl-CoA reductase, farnesyl pyrophosphate synthase, squalene synthase, small rubber particle protein, allene oxide synthase, and cis-prenyl transferase. Gene expression was studied for field-grown plants during the normal course of seasonal variation in temperature (monthly average maximum 41.7 °C to minimum 0 °C, from November 2005 through March 2007) and rubber transferase enzymatic activity was also evaluated. Levels of gene expression did not correlate with air temperatures nor with rubber transferase activity. Interestingly, a sudden increase in night temperature 10 days before harvest took place in advance of the highest CPT gene expression level.

Draft genome sequence of the rubber tree Hevea brasiliensis

“…We validated the expression of these genes from leaf and/or latex cDNA pools, detecting at least one isoform for the majority of the gene families (in Additional file 1: Table S16). We also made a comparison with the ESTs obtained from the rubber-producing bark tissue of guayule [31]. We found that 360 of the H. brasiliensis genes were represented in the guayule ESTs, of which 205 showed more than 70% sequence identity with the best match (in Additional file 2: Table S17).…”

Small rubber particle proteins from Taraxacum brevicorniculatum promote stress tolerance and influence the size and distribution of lipid droplets and artificial poly(cis‐1,4‐isoprene) bodies

“…Interestingly, we observed the premature induction of TbSRPP1–3 under cold stress, which is known to promote rubber biosynthesis in guayule and can also induce the laticifer‐specific HbSRPP promoter in T . brevicorniculatum , the latter also being activated by light and by rubber tapping (Cornish and Backhaus, ; Ponciano et al ., ; Tata et al ., ; Guo et al ., ). The proposed phylogenetic origin of TbSRPPs suggests they may be involved in stress responses, enabling them to promote rubber production under certain environmental conditions.…”

Natural rubber biosynthesis in plants, the rubber transferase complex, and metabolic engineering progress and prospects

“…However, overexpression of HMGR only caused increased rubber yield in young P. argentatum plants under controlled environment; these increases were not maintained in field‐grown transgenics, although an interesting correlation of expression level and heat tolerance was observed (Dong et al ., ). Transcriptome analysis of cold‐acclimated P. argentatum ESTs (a total of 11 748) found that most of the ESTs were from genes encoding stress‐related proteins, while only just 1% of the ESTs were identified as rubber biosynthesis‐related (Ponciano et al ., ). Also, as in H. brasiliensis , a multigene family encodes the P. argentatum HMGS and HMGR (Ponciano et al ., ).…”