Genes expressed in the latex of Hevea brasiliensis

Abstract

Rubber (cis-1,4-polyisoprene), an important raw material for many industrial uses, is synthesized in the latex of Hevea brasiliensis (Willd. ex A. Juss.) Müll. Arg. We postulated that the genes uniquely or preferentially expressed in the latex may be important for rubber biosynthesis. We constructed cDNA libraries from the latex of H. brasiliensis to investigate the genes expressed in the latex by single-run partial sequencing of the cDNA clones. Sequence analyses identified 245 expressed sequence tags (ESTs), of which 57% showed homology to previously described sequences in public databases. About 16% of the database-matched ESTs encode rubber biosynthesis-related proteins such as rubber elongation factor (REF) and small rubber particle protein (SRPP). The second most frequent transcripts next to rubber biosynthesis-related genes were defense genes and protein metabolism-related genes (12.6% each). About 27% of the database-matched ESTs had sequence homology with genes of unknown function. Among the redundantly expressed genes, REF was the most frequently expressed (6.1%), followed by SRPP (3.7%) and HbLAR (2.9%). Northern blot analyses showed that ten (71%) of the 14 ESTs studied were expressed at a higher level in latex than in leaves.

Identification of expression profiles of tapping panel dryness (TPD) associated genes from the latex of rubber tree (Hevea brasiliensis Muell. Arg.)

“…The size of Myb and TCTP genes was 970 and 670 bp, respectively. The sequences were similar to the Myb and the TCTP genes reported earlier (Chen et al 2003;Han et al 2000). As predicted from the SSH results and RT-PCR (Fig.…”

Molecular Identification and Characterization of a Gene Associated with the Onset of Tapping Panel Dryness (TPD) Syndrome in Rubber Tree (Hevea brasiliensis Muell.) by mRNA Differential Display

“…Both analyses showed that the mRNA transcript accumulation was decreased by 2-5 folds in TPDaffected tree, compared to healthy one. It is interesting to note that the accumulation of HbTOM20 mRNA transcript level in different clones (PB217 [ PB235 [ RRII105) is proportional to the percent of TPD occurrence of these clones: PB217 (5-10) [ PB235 (10)(11)(12)(13)(14)(15) [ RRII105 (15)(16)(17)(18)(19)(20) [3]. As expected, the HbTOM20 mRNA transcripts level was significantly down-regulated in TPD-affected trees of all the clones tested (Fig.…”

“…The latex of Hevea is a rubber containing cytoplasm expelled from the laticifers, upon controlled bark wounding or tapping. When severed during tapping, high turgor pressure inside the laticifers expels latex which contains 30-50% of cis-1,4 polyisoprene [15]. The laticifers are periodically emitted from the cambium as single cells, forming latex cell mantels in the soft bark of the rubber tree [11].…”

UPAYA PERBAIKAN GENETIK DAN PENYEDIAAN BIBIT TANAMAN KARET (Hevea brasiliensis Muell. Arg.) MELALUI PENDEKATAN BIOTEKNOLOGI

“…Teknik rekayasa genetika pada tanaman karet semakin lebih mudah dilakukan dengan telah berhasil disusunnya konsep genom (Rahman et al, 2013) dan pustaka cDNA dari lateks (Han et al, 2000;Chotigeat et al, 2010). Hasil penelitian tersebut menunjukkan jumlah gen diperkirakan sebesar 68.955 gen, dan 12,7 % dari jumlah gen tersebut merupakan gen unik pada Hevea.…”