國(guó)際蚜蟲基因組聯(lián)盟已成功地對(duì)農(nóng)業(yè)害蟲“蚜蟲”進(jìn)行了基因組測(cè)序,。根據(jù)對(duì)蚜蟲基因信息的解讀,，研究人員期冀將來能開發(fā)出防治蚜蟲的有效方法,。該研究成果發(fā)表于2月23日美國(guó)《公共科學(xué)圖書館·生物學(xué)》雜志的網(wǎng)絡(luò)版上,。
蚜蟲是以植物的韌皮部流體為食物的小型昆蟲，不但以集團(tuán)形式吸取植物的養(yǎng)分,，而且是傳播植物病毒的媒介,，給全世界農(nóng)作物帶來巨大災(zāi)害。蚜蟲能夠收納合成營(yíng)養(yǎng)成分的共生細(xì)菌,，并從一億年前逐代相傳,，因此與各種微生物有著密切的關(guān)系。蚜蟲還可以適應(yīng)環(huán)境條件的變化,，不斷在單性繁殖和有性繁殖之間切換,，變換自如地產(chǎn)生出各種表現(xiàn)形態(tài)。蚜蟲由于具有非常奇特的生物學(xué)特性,，也因而成為基礎(chǔ)生物學(xué)研究重要的生物模型,。
國(guó)際蚜蟲基因組聯(lián)盟的研究小組在北美采集到“豌豆蚜蟲”，并提取其DNA,，利用鳥槍法（shotgun sequence method）對(duì)其基因序列進(jìn)行排序,。在全基因組5億個(gè)堿基對(duì)中，繪制了其中約4億5000萬個(gè)堿基對(duì)的序列圖譜,。國(guó)際研究小組利用計(jì)算機(jī)對(duì)遺傳基因進(jìn)行了預(yù)測(cè),，并對(duì)其中部分基因?qū)嵭辛耸謩?dòng)結(jié)構(gòu)驗(yàn)證，以對(duì)自動(dòng)預(yù)測(cè)結(jié)果進(jìn)行修正,。
結(jié)果發(fā)現(xiàn),，蚜蟲在昆蟲中具有數(shù)量最多的遺傳基因35000個(gè)。研究人員證實(shí)蚜蟲具有非常獨(dú)特的基因組特性：大量基因重復(fù),，重復(fù)基因在昆蟲中屬最多,，約達(dá)2500組，總數(shù)13000個(gè)基因,；免疫相關(guān)基因大量缺失；代謝相關(guān)基因組與蚜蟲巴克納氏菌構(gòu)成輔助代謝體系,；從共生細(xì)菌獲得10種以上的基因,，多發(fā)現(xiàn)于菌細(xì)胞。
研究人員認(rèn)為,，大量重復(fù)基因的發(fā)現(xiàn),，如單性生殖基因、信號(hào)傳輸復(fù)制基因和對(duì)病毒媒介起重要作用的膜輸送相關(guān)基因,，對(duì)揭開蚜蟲獨(dú)特特性的分子基礎(chǔ)起到了重要作用,。蚜蟲放棄對(duì)來自外部微生物的攻擊能力，使其成功地與各種微生物形成共生,。蚜蟲與共生細(xì)菌等各種異種生物就像一個(gè)生物一樣協(xié)調(diào)代謝,，構(gòu)筑成二者不可分的關(guān)系,。
人們一般使用藥物對(duì)蚜蟲進(jìn)行防治，但化學(xué)藥物防治害蟲損害人類健康及增加環(huán)境的負(fù)擔(dān),。近年來,，已出現(xiàn)了對(duì)農(nóng)藥具有耐藥性的蚜蟲群。此次蚜蟲基因組測(cè)序研究,，不但使人們對(duì)蚜蟲的特異生物學(xué)特性有了更深入的了解,，還將對(duì)發(fā)生學(xué)、進(jìn)化學(xué),、生態(tài)學(xué),、動(dòng)物學(xué)、微生物學(xué)等生物學(xué)的廣泛領(lǐng)域造成了巨大影響,。（生物谷Bioon.com）
生物谷推薦原始出處：
PLoS Biol 8(2): e1000313. doi:10.1371/journal.pbio.1000313
Genome Sequence of the Pea Aphid Acyrthosiphon pisum
The International Aphid Genomics Consortium
Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetabolous insect provides an outgroup to the multiple published genomes of holometabolous insects. Pea aphids are host-plant specialists, they can reproduce both sexually and asexually, and they have coevolved with an obligate bacterial symbiont. Here we highlight findings from whole genome analysis that may be related to these unusual biological features. These findings include discovery of extensive gene duplication in more than 2000 gene families as well as loss of evolutionarily conserved genes. Gene family expansions relative to other published genomes include genes involved in chromatin modification, miRNA synthesis, and sugar transport. Gene losses include genes central to the IMD immune pathway, selenoprotein utilization, purine salvage, and the entire urea cycle. The pea aphid genome reveals that only a limited number of genes have been acquired from bacteria; thus the reduced gene count of Buchnera does not reflect gene transfer to the host genome. The inventory of metabolic genes in the pea aphid genome suggests that there is extensive metabolite exchange between the aphid and Buchnera, including sharing of amino acid biosynthesis between the aphid and Buchnera. The pea aphid genome provides a foundation for post-genomic studies of fundamental biological questions and applied agricultural problems.
