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Title: RHIZOSPHERE COLONIZATION OF OILSEED RAPE BY PSEUDOMONAS ALCALIGENES A9(LACZ)

Author
item HU, X - CHINESE ACAD SCI.
item LIU, S - CHINESE ACAD SCI.
item Roberts, Daniel

Submitted to: Chinese Journal of Oil Crops Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/30/2002
Publication Date: 12/1/2002
Citation: Hu, X., Liu, S., Roberts, D.P. 2002. Rhizosphere colonization of oilseed rape by pseudomonas alcaligenes a9(lacz). Chinese Journal of Oil Crops Sciences. 24:54-56.

Interpretive Summary: Soilborne plant pathogens cause diseases that result in major economic losses to growers and farmers worldwide. Biological control of plant diseases is an environmentally friendly and promising alternative to the use of chemicals for control of these important soilborne plant pathogens. This journal article (to be published in Chinese) describes the colonization behavior of the genetically-tagged strain Pseudomonas alcaligenes A9(LacZ) in the rhizosphere of oilseed rape. Pseudomonas alcaligenes A9(LacZ) is a promising biocontrol strain for the control of soilborne seedling diseases of this crop. When introduced into soil as a seed treatment, populations of this bacterium decrease profoundly with increasing distance from the hypocotyl and with time after sowing. This information will be useful to scientists devising biological control strategies for the suppression of soilborne diseases of oilseed rape.

Technical Abstract: Root colonization of oilseed rape by Pseudomonas alcaligenes A9(LacZ) in rhizosphere microcosms was investigated with the aid of the lacZ marker gene. Rape seeds were pelletized with A9(LacZ), an effective bacterial strain for promotion of rape seedling growth . Results indicated that A9(LacZ) populations decreased with increasing distance down oilseed rape roots and with time after sowing. Populations of A9(LacZ) were not detectable on roots more than 8 cm from the hypocotyl base. The population density of A9(LacZ) on roots reached the maximum of 7.6×105 cfu·g-1 12 days after sowing, and declined rapidly to relatively stable and lower populations (1.1×102 cfu·g-1) in rhizosphere microcosms 30 days after sowing.