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总结一下根瘤菌对非豆植物的影响, 初稿是这样,待整理.
A marked increase in environmental awareness and a concern for sustainable agriculture has occurred
over the last decade. This awareness has highlighted the need both to further promote plant growth
and yields and also to find environmentally benign replacements for industrially produced nitrogen
fertilisers.
Agriculturalists have searched for various soil bacteria that might make reliable contributions to the
growth of non-legume cereals and have found a group of bacteria which intimately associate with rice.
Many of these rice-associating strains are also nitrogen-fixing. Recently Rhizobium bacteria, which
normally nodulate legumes, have been shown to associate intimately with the roots of rice plants.
The possibility of establishing a more effective type of Rhizobium-non-legume interaction is
potentially available in rice because many of the plant compounds that could interact and stimulate
rhizobia are also present in rice roots. However, the interaction of introduced bacterial strains with
rice cultivars used in Australia had not been examined. This project set out to describe the types of
interactions which occur between seedlings of Australian rice cultivars and a range of bacterial and
Rhizobium strains. It details the extent and pattern of rice plant colonisation, as well as degree to
which the growth of rice seedlings is influenced, and how environmental factors can influence the
outcome. Finally, it identifies genetic regions within a model bacterial strain that are essential to the
interaction of the bacteria with rice.
This project was funded from industry revenue which is matched by funds provided by the Federal
Government.
This report, a new addition to RIRDC’s diverse range of over 700 research publications, forms part of
our Rice R&D program, which aims to improve the profitability and sustainability of the Australian
rice industry.
1.根瘤菌与水稻之间的关系:
生态学报 外源基因标记的紫云英根瘤菌在水稻根部的定殖研究 Study on root colonazition of rice by genes marked Rhizobium astragalus 张晓霞 王平 冯新梅 胡正嘉 摘 要:前期研究中已证实紫云英根瘤菌(?Rhizobium astragalus?)JS5A16菌株对水稻生长有一定的促生作用,利用?gusA?基因标记的JS5A16菌株(编号为JS5A16G)接种水稻种子并检测其在水稻(汕优63)生长初期的根圈定殖动态及分布.结果表明菌株JS5A16G在水稻出苗后2d根圈定殖密度大量增加,第4天达到最大值16d后趋于稳定.将水稻根表面灭菌后,检测菌株JS5A16G在根内的定殖情况,发现在"汕优63"出苗后2d检测不出菌株JS5A16G,第4天可检测出.根部直接染色显示,菌株JS5A16G在根部的分布并不均匀,主要是在根系的某些部位形成微菌落.同时利用?luxAB?发光酶基因标记紫云英根瘤菌JS5A16菌株(编号为JS5 A16L)研究其在不同品种水稻根部的定殖动态.结果表明,菌株JS5A6L在不同水稻品种"汕优63"、"汕优64"和"马协118-2"根部的定殖密度不同且可以进入不同水稻品种的根内 .在整个水稻生长期内菌株JS5A16L在"汕优64"根部的定殖密度明显高于其在"汕优63" 根部的定殖密度,在"马协118-2" 的定殖密度与其在"汕优63"、"汕优64" 根部相比没有显著差异.但菌株JS5A16L在不同水稻根部的定殖动态相似,数量均在水稻生长到60~7 5d时(即水稻的孕穗期)达到最高值. |
基金项目:国家自然科学基金资助项目(39970027) 作者简介:张晓霞(1974~),女,内蒙古赤峰人,现在中国农业科学院土壤肥料研究所工作,主要从事农业微生物菌种资源的收集、保藏及利用研究.王平,通讯作者Author for correspondence,E-mail:pwang118@hotmail.com 作者单位:张晓霞(华中农业大学生命科学技术学院农业微生物重点实验室,武汉,430070) 王平(华中农业大学生命科学技术学院农业微生物重点实验室,武汉,430070) 冯新梅(华中农业大学生命科学技术学院农业微生物重点实验室,武汉,430070) 胡正嘉(华中农业大学生命科学技术学院农业微生物重点实验室,武汉,430070) 参考文献: [1]De Bruiji. Potential and pitfalls of trying to extend symbioti interactions o f nitrogen-fixing organisms to prensently non-nodulated plants, such as rice. ?Plant and Soil,? 1995, 174:225~240. |
收稿日期:2002年1月18日 修稿日期:2002年7月11日 出版日期:2003年4月1日 |
F.B. Dazzo, Y.G. Yanni, R. Rizk, F.J. de Bruijn, J. Rademaker, A. Squartini, V. Corich, P. Mateos, E. Mart韓ez-Molina, E. Vel醶quez, J.C. Biswas, R.J. Hernandez, J.K. Ladha, J. Hill, J. Weinman, B.G. Rolfe, M. Vega-Hern醤dez, J.J. Bradford, R.I. Hollingsworth, P. Ostrom, E. Marshall, T. Jain, G. Orgambide, S. Philip-Hollingsworth, E. Triplett, K.A. Malik, J. Maya-Flores, A. Hartmann, M. Umali-Garcia, and M.L. Izaguirre-Mayoral
This chapter summarizes our collaborative project to search for natural, intimate associations between rhizobia and rice (Oryza sativa), assess their impact on plant growth, and ultimately exploit those that can enhance grain yield with less dependence on nitrogen fertilizer inputs. Two cycles of field and laboratory studies have indicated that diverse indigenous populations of the clover root-nodule symbiont, Rhizobium leguminosarum bv. trifolii, intimately colonize rice roots in cultivated fields of the Egyptian Nile Delta, where rice has been rotated successfully with berseem clover (Trifolium alexandrinum) since antiquity. Certain strain/variety interactions significantly expand rice root architecture, enhance the uptake of several plant nutrients, and increase plant biomass under laboratory and greenhouse conditions. Preliminary results indicating statistically significant increases in grain yield and agronomic fertilizer N-use efficiency following inoculation have been obtained.
We are now examining various basic and applied aspects of this beneficial Rhizobium-rice association, such as its ecology, physiology, biochemistry, and molecular biology and the identification of the underlying mechanisms of plant growth promotion operative in this beneficial association. We are also further assessing selected rhizobial strains to perform as beneficial biofertilizer inoculants for rice under field conditions. Certain strains of these rice-adapted rhizobia colonize the surface and, within limited regions of the interior of lateral roots of rice seedlings, secrete indoleacetic acid and gibberellin phytohormones in vitro, and extracellularly solubilize precipitated phosphates. Various acetylene reduction assays and 15N-based studies do not support a role of biological nitrogen fixation in the positive plant growth-promotion response of this Rhizobium-rice association. This natural, intimate Rhizobium-rice association represents a unique experimental system suitable for both basic and applied studies on beneficial rice-bacteria interactions. This association of dissimilar organisms living together may also turn out to offer potential benefits to enhance the sustainable agriculture of rice, the most important cereal crop of the developing world.
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