一個(gè)國際科研小組9日發(fā)布報(bào)告說，他們完成了對馬鈴薯晚疫病病菌的基因測序,，這有助于找到對付這一病菌的新手段,。晚疫病病菌曾導(dǎo)致歷史上著名的愛爾蘭大饑荒。
這項(xiàng)研究由美英等多國研究人員聯(lián)合完成,。馬鈴薯晚疫病病菌基因測序結(jié)果顯示,，與同類生物相比，該病菌有大得出奇的基因圖譜,，其中74％都是由重復(fù)出現(xiàn)的“轉(zhuǎn)位子”組成,。
研究人員說，這是一個(gè)“瘋狂”的比例,，通常微生物基因圖譜中有25％的“轉(zhuǎn)位子”就已經(jīng)很多了,。“轉(zhuǎn)位子”是具有特定功能的基因片段,，它可以自我復(fù)制并在基因序列中四處移動(dòng)，晚疫病病菌正是靠這些“轉(zhuǎn)位子”的作用侵害馬鈴薯,。研究人員認(rèn)為,，晚疫病病菌基因如此演化是為了保持一個(gè)龐大的“武器庫”，便于迅速適應(yīng)環(huán)境變化,。
一名馬鈴薯育種專家在評論上述成果時(shí)說,，有時(shí)“好不容易費(fèi)15年時(shí)間培育出一種有抵抗力的新品種，晚疫病病菌卻只用幾年就把它打敗”,，現(xiàn)在掌握了該病菌的基因圖譜和“武器庫”特點(diǎn),，將有助于研發(fā)能有效對付它的基因手段。
晚疫病病菌會(huì)損害馬鈴薯的葉子和根莖,，它在19世紀(jì)導(dǎo)致愛爾蘭大面積馬鈴薯絕收,，約有100萬人因此死亡，還有數(shù)百萬人因這一病蟲害移居海外,。據(jù)估算,，這一病菌目前仍給全球農(nóng)業(yè)造成每年約67億美元的損失。(生物谷Bioon.com)
生物谷推薦原始出處：
Nature 9 September 2009 | doi:10.1038/nature08358
Genome sequence and analysis of the Irish potato famine pathogen Phytophthora infestans
Brian J. Haas1,35, Sophien Kamoun2,3,35, Michael C. Zody1,4, Rays H. Y. Jiang1,5, Robert E. Handsaker1, Liliana M. Cano2, Manfred Grabherr1, Chinnappa D. Kodira1,36, Sylvain Raffaele2, Trudy Torto-Alalibo3,36, Tolga O. Bozkurt2, Audrey M. V. Ah-Fong6, Lucia Alvarado1, Vicky L. Anderson7, Miles R. Armstrong8, Anna Avrova8, Laura Baxter9, Jim Beynon9, Petra C. Boevink8, Stephanie R. Bollmann10, Jorunn I. B. Bos3, Vincent Bulone11, Guohong Cai12, Cahid Cakir3, James C. Carrington13, Megan Chawner14, Lucio Conti15, Stefano Costanzo16, Richard Ewan15, Noah Fahlgren13, Michael A. Fischbach17, Johanna Fugelstad11, Eleanor M. Gilroy8, Sante Gnerre1, Pamela J. Green18, Laura J. Grenville-Briggs7, John Griffith14, Niklaus J. Grünwald10, Karolyn Horn14, Neil R. Horner7, Chia-Hui Hu19, Edgar Huitema3, Dong-Hoon Jeong18, Alexandra M. E. Jones2, Jonathan D. G. Jones2, Richard W. Jones20, Elinor K. Karlsson1, Sridhara G. Kunjeti21, Kurt Lamour22, Zhenyu Liu3, LiJun Ma1, Daniel MacLean2, Marcus C. Chibucos23, Hayes McDonald24, Jessica McWalters14, Harold J. G. Meijer5, William Morgan25, Paul F. Morris26, Carol A. Munro27, Keith O'Neill1,36, Manuel Ospina-Giraldo14, Andrés Pinzón28, Leighton Pritchard8, Bernard Ramsahoye29, Qinghu Ren30, Silvia Restrepo28, Sourav Roy6, Ari Sadanandom15, Alon Savidor31, Sebastian Schornack2, David C. Schwartz32, Ulrike D. Schumann7, Ben Schwessinger2, Lauren Seyer14, Ted Sharpe1, Cristina Silvar2, Jing Song3, David J. Studholme2, Sean Sykes1, Marco Thines2,33, Peter J. I. van de Vondervoort5, Vipaporn Phuntumart26, Stephan Wawra7, Rob Weide5, Joe Win2, Carolyn Young3, Shiguo Zhou32, William Fry12, Blake C. Meyers18, Pieter van West7, Jean Ristaino19, Francine Govers5, Paul R. J. Birch34, Stephen C. Whisson8, Howard S. Judelson6 & Chad Nusbaum1
Phytophthora infestans is the most destructive pathogen of potato and a model organism for the oomycetes, a distinct lineage of fungus-like eukaryotes that are related to organisms such as brown algae and diatoms. As the agent of the Irish potato famine in the mid-nineteenth century, P. infestans has had a tremendous effect on human history, resulting in famine and population displacement1. To this day, it affects world agriculture by causing the most destructive disease of potato, the fourth largest food crop and a critical alternative to the major cereal crops for feeding the world's population1. Current annual worldwide potato crop losses due to late blight are conservatively estimated at $6.7 billion2. Management of this devastating pathogen is challenged by its remarkable speed of adaptation to control strategies such as genetically resistant cultivars3, 4. Here we report the sequence of the P. infestans genome, which at 240 megabases (Mb) is by far the largest and most complex genome sequenced so far in the chromalveolates. Its expansion results from a proliferation of repetitive DNA accounting for 74% of the genome. Comparison with two other Phytophthora genomes showed rapid turnover and extensive expansion of specific families of secreted disease effector proteins, including many genes that are induced during infection or are predicted to have activities that alter host physiology. These fast-evolving effector genes are localized to highly dynamic and expanded regions of the P. infestans genome. This probably plays a crucial part in the rapid adaptability of the pathogen to host plants and underpins its evolutionary potential.
