Pedosphere 20(4): 505--514, 2010
ISSN 1002-0160/CN 32-1315/P
©2010 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Composition of wheat rhizosphere antagonistic bacteria and wheat sharp eyespot as affected by rice straw mulching |
CHEN Huai-Gu1,2, CAO Qi-Guang2,3, XIONG Gui-Lin2,3, LI Wei2, ZHANG Ai-Xiang2, YU Han-Shou2 and WANG Jin-Sheng1 |
1 College of Plant Protection, Nanjing Agricultural University, Nanjing 210095 (China);
2 Institute of Plant Protection, Jiangsu Academy of Agricultural, Nanjing 210014 (China);
3 College of Life Sciences, Nanjing Agricultural University, Nanjing 210095 (China) |
| ABSTRACT |
| To assess the effect of rice straw mulching on changes of antagonistic bacteria and the incidence of wheat sharp eyespot, a multi-year field study was performed to compare unmulched plots and the plots mulched with rice straw for two or three years. Bacterial and fungal populations were evaluated in the cultures prepared from the wheat rhizosphere and bulk soils. Rice straw mulching increased the number of pseudomonas colony forming units in wheat rhizosphere and bulk soils. The proportion of total bacteria that were fluorescent pseudomonads was higher in mulched than in unmulched soil. Bacterial isolates antagonistic to Rhizoctonia cerealis were identified using an inhibition zone test. A series of these isolates were typed by partial sequencing of the 16S rRNA gene. Pseudomonads had higher antagonistic activity against R. cerealis than other species, and more than 80% of rhizosphere fluorescent pseudomonads were antagonistic to R. cerealis. The disease indices were lower in the mulched plots than in the unmulched control. These results suggest that rice straw mulching in a rice-wheat rotation increases the number of fluorescent pseudomonads. Additionally, these fluorescent pseudomonads may contribute to the control of wheat sharp eyespot. |
| Key Words: antagonistic microorganisms, disease control, fluorescent pseudomonads, Rhizoctonia cerealis, rice-wheat rotation |
| Citation: Chen, H. G., Cao, Q. G., Xiong, G. L., Li, W., Zhang, A. X., Yu, H. S. and Wang, J. S. 2010. Composition of wheat rhizosphere antagonistic bacteria and wheat sharp eyespot as affected by rice straw mulching. Pedosphere. 20(4): 505-514. |
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