Insights into rubber biosynthesis from transcriptome analysis of Hevea brasiliensis latex
Insights into rubber biosynthesis from transcriptome analysis of Hevea brasiliensis latex
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DOI：
10.1093/jxb/erm093
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发表时间：
2007-01-01
影响因子：
6.9
通讯作者：
Yeang, Hoong-Yeet
中科院分区：
文献类型：
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作者：
Chow, Keng-See;Wan, Kiew-Lian;Yeang, Hoong-Yeet
巴西橡胶树是商业生产天然橡胶（顺式 - 聚异戊二烯）种植最广泛的树种。在本研究中，为了分析乳胶转录图谱并重点关注橡胶生物合成相关基因，从橡胶树的乳胶中产生了10040个表达序列标签（EST），乳胶代表了一种单一细胞类型的细胞质成分。在对EST序列进行质量编辑和组装后，共获得3441个独特转录本（UT）。根据基因本体论惯例对UT进行功能分类表明，73.8%与功能未知的基因相关。在高表达的EST中，很大一部分编码与橡胶生物合成以及应激或防御反应相关的蛋白质。编码属于三个蛋白质家族的橡胶粒子膜蛋白（RPMP）的序列占EST的12%。对这些EST的特性分析揭示了9种RPMP变体（7.9 - 27 kDa），包括14 kDa的橡胶延伸因子（REF）和22 kDa的小橡胶粒子蛋白（SRPP）。利用针对REF和SRPP的抗体显示了乳胶中多种RPMP异构体的表达。EST和定量逆转录 - 聚合酶链反应（QRT - PCR）分析均表明REF和SRPP是乳胶中最丰富的转录本。除了橡胶生物合成外，比较序列分析表明RPMP与植物界中具有应激相关功能的序列高度相似。本文讨论了在转录本丰度和差异基因表达的背景下RPMP功能在顺式 - 聚异戊二烯生物合成中的意义。
Hevea brasiliensis is the most widely cultivated species for commercial production of natural rubber (cis-polyisoprene). In this study, 10 040 expressed sequence tags (ESTs) were generated from the latex of the rubber tree, which represents the cytoplasmic content of a single cell type, in order to analyse the latex transcription profile with emphasis on rubber biosynthesis-related genes. A total of 3441 unique transcripts (UTs) were obtained after quality editing and assembly of EST sequences. Functional classification of UTs according to the Gene Ontology convention showed that 73.8% were related to genes of unknown function. Among highly expressed ESTs, a significant proportion encoded proteins related to rubber biosynthesis and stress or defence responses. Sequences encoding rubber particle membrane proteins (RPMPs) belonging to three protein families accounted for 12% of the ESTs. Characterization of these ESTs revealed nine RPMP variants (7.9-27 kDa) including the 14 kDa REF (rubber elongation factor) and 22 kDa SRPP (small rubber particle protein). The expression of multiple RPMP isoforms in latex was shown using antibodies against REF and SRPP. Both EST and quantitative reverse transcription-PCR (QRT-PCR) analyses demonstrated REF and SRPP to be the most abundant transcripts in latex. Besides rubber biosynthesis, comparative sequence analysis showed that the RPMPs are highly similar to sequences in the plant kingdom having stress-related functions. Implications of the RPMP function in cis-polyisoprene biosynthesis in the context of transcript abundance and differential gene expression are discussed.