一个国际科学家小组近日通过分析苔藓基因组发现，苔藓基因的丰富性超乎想象，并且具有许多独特的变异。根据苔藓在植物进化树上的独特位置，这一发现将有助于揭示植物从水生到陆生的过程。相关论文12月13日在线发表于《科学》（Science）杂志上。
苔藓是一种古老的植物，它大约于4.5亿年前与开花植物的祖先进化分离开来。在进化道路上，它与其它种类的植物一样，都需要克服由水生到陆生所遭遇到的一系列挑战。很多其它种植物进化出了维管组织（vascular tissues），用来输送水分和种子以在干旱的环境中存活下来；但是苔藓并没有进化出维管组织及类似功能，它似乎采取了另外的策略。
在最新的研究中，美国华盛顿大学的发育生物学家Ralph Quatrano和研究小组，测序了被广泛研究的一种苔藓P. patens的基因组，并与水稻、开花植物拟南芥（Arabidopsis）及单细胞藻类的基因组进行了比较。结果发现这种苔藓的基因数达到35000个，其中20%为研究人员前所未见，而且很可能是P. patens独有的。
Quatrano认为这一结果非常令人吃惊。他表示，能帮助干枯苔藓回复生命的基因同样也存在于其它陆生植物中，这表明这种基因在更早的时间就已出现。另外，P. patens具有应对水压力的基因，表明它进化出了独立的处理水缺乏的方法。此外，P. patens还具有修复DNA的基因，以应付日照造成的损害。Quatrano说，看起来好像是P. patens的祖先在进化早期复制了整个基因组，这就解放了一些基因，使它们具有了新的功能。
美国科罗拉多大学进化生物学家William Friedman认为，苔藓基因组具有揭示植物由水生到陆生转变过程的潜力，这令人非常兴奋。不过，美国佛罗里达大学的进化生物学家Pamela Soltis却指出，研究人员并没有仔细分析进化树，而苔藓和水稻之间的进化差距就好比是鱼和人类之间的差距，这意味着要完全弄清植物由水生到陆生的过程，还需要做更多的测序。（科学网 梅进/编译）
原始出处:
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Published Online December 13, 2007
Science DOI: 10.1126/science.1150646
Submitted on September 18, 2007
Accepted on November 21, 2007
The Physcomitrella Genome Reveals Evolutionary Insights into the Conquest of Land by Plants
Stefan A. Rensing 1, Daniel Lang 1, Andreas D. Zimmer 1, Astrid Terry 2, Asaf Salamov 3, Harris Shapiro 3, Tomoaki Nishiyama 4, Pierre-François Perroud 5, Erika A. Lindquist 3, Yasuko Kamisugi 6, Takako Tanahashi 7, Keiko Sakakibara 8, Tomomichi Fujita 9, Kazuko Oishi 10, Tadasu Shin-I 10, Yoko Kuroki 11, Atsushi Toyoda 11, Yutaka Suzuki 12, Shin-ichi Hashimoto 13, Kazuo Yamaguchi 14, Sumio Sugano 12, Yuji Kohara 15, Asao Fujiyama 16, Aldwin Anterola 17, Setsuyuki Aoki 18, Neil Ashton 19, W. Brad Barbazuk 20, Elizabeth Barker 19, Jeffrey L. Bennetzen 21, Robert Blankenship 5, Sung Hyun Cho 5, Susan K. Dutcher 22, Mark Estelle 23, Jeffrey A. Fawcett 24, Heidrun Gundlach 25, Kousuke Hanada 26, Alexander Heyl 27, Karen A. Hicks 28, Jon Hughes 29, Martin Lohr 30, Klaus Mayer 25, Alexander Melkozernov 31, Takashi Murata 7, David R. Nelson 32, Birgit Pils 33, Michael Prigge 23, Bernd Reiss 34, Tanya Renner 35, Stephane Rombauts 24, Paul J. Rushton 36, Anton Sanderfoot 37, Gabriele Schween 1, Shin-Han Shiu 38, Kurt Stueber 34, Frederica L. Theodoulou 39, Hank Tu 3, Yves Van de Peer 24, Paul J. Verrier 40, Elizabeth Waters 35, Andrew Wood 17, Lixing Yang 21, David Cove 41, Andrew C. Cuming 6, Mitsuyasu Hasebe 42, Susan Lucas 2, Brent D. Mishler 43, Ralf Reski 1, Igor V. Grigoriev 3, Ralph S. Quatrano 5*, Jeffrey L. Boore 44
1 Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestrasse 1, D-79104 Freiburg, Germany.
2 DOE Joint Genome Institute and Lawrence Livermore National Laboratory, 2800 Mitchell Drive, Walnut Creek, CA 94598, USA.
3 DOE Joint Genome Institute and Lawrence Berkeley National Laboratory, 2800 Mitchell Drive, Walnut Creek, CA 94598, USA.
4 Advanced Science Research Center, Kanazawa University, 13-1 Takara-machi Kanazawa, 920-0934, Japan.
5 Department of Biology, Washington University, 1 Brookings Drive, St. Louis, MO 63130–4899, USA.
6 Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, UK.
7 National Institute for Basic Biology, Okazaki 444-8585, Japan.; Department of Basic Biology, School of Life Science, The Graduate University for Advanced Studies, Okazaki 444-8585, Japan.
8 School of Biological Sciences, Monash University, Clayton Campus, Melbourne, VIC 3800, Australia.
9 Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan.
10 Genome Biology Laboratory, Center for Genetic Resource Information, National Institute of Genetics, Mishima 411-8540, Japan.
11 RIKEN Genomic Sciences Center, Kanagawa 230-0045, Japan.
12 Laboratory of Functional Genomics, Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Tokyo 108-8639, Japan.
13 Department of Molecular Preventive Medicine, School of Medicine, The University of Tokyo, Tokyo 113-8654, Japan.
14 Advanced Science Research Center, Kanazawa University, 13-1 Takara-machi Kanazawa, 920-0934, Japan.; Division of Life Science, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa 920-1192, Japan.
15 Genome Biology Laboratory, Center for Genetic Resource Information, National Institute of Genetics, Mishima 411-8540, Japan.; Department of Genetics, School of Life Science, The Graduate University for Advanced Studies, Mishima 411-8540, Japan.
16 RIKEN Genomic Sciences Center, Kanagawa 230-0045, Japan.; National Institute of Informatics, Tokyo 101-8403, Japan.; Department of Informatics, School of Multidisciplinary Sciences, The Graduate University for Advanced Studies, Tokyo 101-8403, Japan.
17 Department of Plant Biology, Southern Illinois University, Carbondale, IL 62901–6509, USA.
18 Life-Science Informatics Unit, Graduate School of Information Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
19 University of Regina, 3737 Wascana Parkway, Regina, SK, Canada S4S 0A2.
20 Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, MO 63132, USA.
21 Department of Genetics, Davison Life Sciences Complex, University of Georgia, Athens, GA 30602–7223, USA.
22 Department of Genetics, Washington University, 660 South Euclid Avenue, St. Louis, MO 63108, USA.
23 Department of Biology, Indiana University, 1001 East Third Street, Bloomington, IN 47405–3700, USA.
24 VIB Department of Plant Systems Biology, Ghent University, Technologie Park 927, 9052 Ghent, Belgium.
25 MIPS/IBI Institute for Bioinformatics, GSF Research Center for Environment and Health, Ingolstaedter Landstrasse 1, D-85764 Neuherberg, Germany.
26 Department of Plant Biology, 166 Plant Biology Building, Michigan State University, East Lansing, MI 48824–1312, USA.; RIKEN Plant Science Center, 1-7-22 Suehiro, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan.
27 Free University, Institute for Biology, Applied Genetics Neubau, Albrecht-Thaer-Weg 6, D-14195 Berlin, Germany.
28 Max-Planck Institute of Plant Breeding Research, Carl-von-Linne-Weg 10, D-50829 Cologne, Germany.; Biology Department, Kenyon College, Gambier, OH 43022, USA.
29 Pflanzenphysiologie, Justus Liebig University, Senckenbergstrasse 3, D-35390 Giessen, Germany.
30 Institute of General Botany, Johannes Gutenberg-University, D-55099 Mainz, Germany.
31 Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287–1604, USA.
32 University of Tennessee-Memphis, 101 I Molecular Science Building, 858 Madison Avenue, Memphis, TN 38163, USA.
33 Department of Bioinformatics, Biozentrum, Am Hubland,Würzburg University, D-97074 Würzburg, Germany.
34 Max-Planck Institute of Plant Breeding Research, Carl-von-Linne-Weg 10, D-50829 Cologne, Germany.
35 Biology Department, San Diego State University, North Life Sciences Room 102, 5500 Campanile Drive, San Diego, CA 92182–4614, USA.
36 Department of Biology, Gilmer Hall, 485 McCormick Road, University of Virginia, Charlottesville, VA 22903, USA.
37 Department of Plant Biology, University of Minnesota, 250 Biological Science Center, 1445 Gortner Avenue, St. Paul, MN 55108, USA.
38 Department of Plant Biology, 166 Plant Biology Building, Michigan State University, East Lansing, MI 48824–1312, USA.
39 Biological Chemistry Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK.
40 Biomathematics and Bioinformatics Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK.
41 Department of Biology, Washington University, 1 Brookings Drive, St. Louis, MO 63130–4899, USA.; Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, UK.
42 National Institute for Basic Biology, Okazaki 444-8585, Japan.; Department of Basic Biology, School of Life Science, The Graduate University for Advanced Studies, Okazaki 444-8585, Japan.; ERATO, Japan Science and Technology Agency, Okazaki 444-8585, Japan.
43 Department of Integrative Biology, 3060 Valley Life Sciences Building, University of California, Berkeley, CA 94720, USA.
44 DOE Joint Genome Institute and Lawrence Berkeley National Laboratory, 2800 Mitchell Drive, Walnut Creek, CA 94598, USA.; Department of Integrative Biology, 3060 Valley Life Sciences Building, University of California, Berkeley, CA 94720, USA.; Genome Project Solutions, 1024 Promenade Street, Hercules, CA 94547, USA.
* To whom correspondence should be addressed.
Ralph S. Quatrano , E-mail: rsq@wustl.edu
We report the draft genome sequence of the model moss Physcomitrella patens and compare its features to those of flowering plants, from which it is separated by more than 400 million years, and unicellular aquatic algae. This reveals genomic changes concomitant with the evolutionary movement to land, including a general increase in gene family complexity, loss of genes associated with aquatic environments (e.g., flagellar arms), acquisition of genes for tolerating terrestrial stresses (e.g., variation in temperature and water availability), and the development of the auxin and abscisic acid signaling pathways for coordinating multicellular growth and dehydration response. The Physcomitrella genome provides a resource for phylogenetic inferences about gene function and for experimental analysis of plant processes through this plant’s unique facility for reverse genetics.
