Cloning and functional analysis of five TERMINAL FLOWER1 (TFL1)/CENTRORADIALIS (CEN)-like genes from Hevea brasiliensis.[Pubmed: 30069883]

Five Terminal Flower1 (TFL1) /Centroradialis (CEN)-like genes were isolated and characterized from rubber tree (Hevea brasiliensis). All genes, except HbCEN1, were found to have conserved genomic organization, characteristic of the phosphatidyl ethanolamine-binding protein (PEBP) family. Over-expression of all of them delayed flowering and altered flower architecture compared with the wild-type counterpart. In addition, since premature-flowering of the terminal bud was successfully overcome in the tfl1-1 mutant of Arabidopsis, all these genes have a potential function similar to TFL1. qRT-PCR analysis showed higher expressions of HbCEN1 and HbCEN2 in the shoot apices and stems of both immature and mature rubber trees than in reproductive organs. HbTFL1-1 and HbTFL1-2 expression was confined to roots of three-month-old seedlings and HbTFL1-3 was significantly higher in the shoot apices of these seedlings. These results suggested that HbCEN1 and HbCEN2 could be associated with development of vegetative growth, whereas HbTFL1-1, HbTFL1-2 and HbTFL1-3 seem to be mainly related with maintenance of juvenility. In addition, four of the five genes displayed variable diurnal expression, HbTFL1-1 and HbTFL1-3 being mainly expressed during the night whereas HbCEN1 and HbCEN2 showed irregular diurnal rhythms. This article is protected by copyright. All rights reserved.

Unrestrictive Identification of Post-Translational Modifications in Hevea Brasiliensis Latex.[Pubmed: 30058361]

The natural rubber latex extracted from the bark of Hevea brasiliensis plays various important roles in today's modern society. Post-translational modifications (PTMs) of the latex proteins are important for the stability and functionality of the proteins. In this study, latex proteins were acquired from the C-serum, lutoids and rubber particle layers of latex and without using prior enrichment steps, they were fragmented using collision-induced dissociation (CID), higher-energy collisional dissociation (HCD) and electron-transfer dissociation (ETD) activation methods. PEAKS 7 were used to search for unspecified PTMs, followed by analysis through PTMs prediction tools to crosscheck both results. There were 73 peptides in 47 proteins from H. brasiliensis protein sequences derived from UniProtKB were identified and predicted to be post-translationally modified. The peptides with PTMs identified include phosphorylation, lysine acetylation, N-terminal acetylation, hydroxylation, and ubiquitination. Most of the PTM's discovered has yet to be reported in UniProt and would provide great assistance in the research of the functional properties of H. brasiliensis latex proteins, as well as being useful biomarkers. The data are available via MassIVE repository with identifier MSV000082419.

Sphaerisporangium rhizosphaerae sp. nov., an actinomycete isolated from the rhizosphere soil of a rubber tree (Hevea brasiliensis Muell. Arg).[Pubmed: 30010529]

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Colletotrichum Species Causing Anthracnose of Rubber Trees in China.[Pubmed: 29992950]

Anthracnose caused by Colletotrichum is one of the most severe diseases of Hevea brasiliensis. However, research on the diversity and geographical distribution of Colletotrichum remains limited in China. In this study, we investigated the phylogenetic diversity of Colletotrichum isolates associated with symptomatic tissues of H.brasiliensis from four provinces of China (Hainan, Guangdong, Guangxi, and Yunnan). Based on multi-locus phylogenetic analyses and phenotypic characteristics, five species were distinguished, including two known species (C. fructicola, C. siamense), one novel species of C. gloeosporioides species complex (C. ledongense), and two novel species of C. acutatum species complex (C. bannanense and C. australisinense). Of these, C. siamense and C. australisinense have been recognized as major causative agents of anthracnose of H. brasiliensis.

[The way of the rubber].[Pubmed: 29912258]

Investigations first by Markham, and then by Spruce, performed in the middle of multiple risks, in the deep of dense jungle, through the wild rivers and facing up natives many times hostile, brought the knowledge of the life cycle of Hevea brasiliensis, the rubber's tree, necessary for take its seeds to Asia, its adaptation to this continent and its culture at industrial level. Undoubtedly these men were the heroes of this history, but they were wise, modest and quite people, so the glory was for an entrepreneur decided and of scare scruples, like Wickham. And Brazil, as a good Latin American nation, sinned of naivety, improvidence and negligence, allowing itself the lost of an unimaginable fortune: the monopoly of the rubber. Because the many applications of rubber in medical practice, the history of this tree may interest our colleagues.

Transcriptome analysis in Hevea brasiliensis latex revealed changes in hormone signalling pathways during ethephon stimulation and consequent Tapping Panel Dryness.[Pubmed: 29855601]

Tapping Panel Dryness (TPD) affects latex production in Hevea brasiliensis. This physiological syndrome involves the agglutination of rubber particles, which leads to partial or complete cessation of latex flow. Latex harvesting consists in tapping soft bark. Ethephon can be applied to stimulate latex flow and its regeneration in laticifers. Several studies have reported transcriptome changes in bark tissues. This study is the first report on deep RNA sequencing of latex to compare the effect of ethephon stimulation and TPD severity. Trees were carefully selected for paired-end sequencing using an Illumina HiSeq 2000. In all, 43 to 60 million reads were sequenced for each treatment in three biological replicates (slight TPD trees without ethephon stimulation, and slight and severe TPD trees with ethephon treatment). Differentially expressed genes were identified and annotated, giving 8,111 and 728 in response to ethephon in slight TPD trees and in ethephon-induced severe TPD trees, respectively. A biological network of responses to ethephon and TPD highlighted the major influence of metabolic processes and the response to stimulus, especially wounding and jasmonate depression in TPD-affected trees induced by ethephon stimulation.