Comparative analysis of latex transcriptomes reveals the potential mechanisms underlying rubber molecular weight variations between the Hevea brasiliensis clones RRIM600 and Reyan7-33–97

Abstract

Background The processabilities and mechanical properties of natural rubber depend greatly on its molecular weight (MW) and molecular weight distribution (MWD). However, the mechanisms underlying the regulation of molecular weight during rubber biosynthesis remain unclear. Results In the present study, we determined the MW and particle size of latex from 1-year-old virgin trees and 30-year-old regularly tapped trees of the Hevea clones Reyan7-33–97 and RRIM600. The results showed that both the MW and the particle size of latex varied between these two clones and increased with tree age. Latex from RRIM600 trees had a smaller average particle size than that from Reyan7-33–97 trees of the same age. In 1-year-old trees, the Reyan7-33–97 latex displayed a slightly higher MW than that of RRIM600, whereas in 30-year-old trees, the RRIM600 latex had a significantly higher MW than the Reyan7-33–97 latex. Comparative analysis of the transcriptome profiles indicated that the average rubber particle size is negatively correlated with the expression levels of rubber particle associated proteins, and that the high-MW traits of latex are closely correlated with the enhanced expression of isopentenyl pyrophosphate (IPP) monomer-generating pathway genes and downstream allylic diphosphate (APP) initiator-consuming non-rubber pathways. By bioinformatics analysis, we further identified a group of transcription factors that potentially regulate the biosynthesis of IPP. Conclusions Altogether, our results revealed the potential regulatory mechanisms involving gene expression variations in IPP-generating pathways and the non-rubber isoprenoid pathways, which affect the ratios and contents of IPP and APP initiators, resulting in significant rubber MW variations among same-aged trees of the Hevea clones Reyan7-33–97 and RRIM600. Our findings provide a better understanding of rubber biosynthesis and lay the foundation for genetic improvement of rubber quality in H. brasiliensis.

Electrically conductive nanocomposites produced by in situ polymerization of pyrrole in pre‐vulcanized natural rubber latex

“…Note that the PPy nanoparticles were distributed circumferentially. As reported in the literature, [ 35,36 ] Hevea brasiliensis produces rubber particles encapsulated with phospholipid monolayer membranes consisting of species‐specific fatty acids, proteins and phospholipids. These particles have a diameter in the range of approximately 3–3000 nm with the majority being around 1000 nm.…”

Identification and Functional Evaluation of Three Polyubiquitin Promoters from Hevea brasiliensis

“…Transcriptomic data provide a better understanding of the global regulation of gene expression, and therefore facilitate the identification of endogenous promoters in economically important crops [26,41]. Several transcriptomes for a number of Hevea clones are now available [34,44,45]. According to the transcriptome database, HbUBI10.1 and HbUBI10.2 genes were highly expressed in various tissues and development stages (Figure 3a), indicating that their promoters should have constitutive activities.…”

Research trend in latex harvesting of rubber tree (Hevea brasiliensis Muell. Arg.) based on bibliographic analysis

“…These typical studies provide a better understanding of the rubber biosynthesis mechanism. Comparative proteomic analysis is also frequently used for studying phloem and xylem development (Prasongsansuk et al, 2020) hormonal stimulation (Choksawangkarn et al, 2020 and rubber molecular weight variation (Xin et al, 2021). Other works tried to identify molecular markers (Bini et al, 2022) and conducted molecular genetic analysis (Amerik et al, 2021), which is pivotal for the breeding program.…”