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The Relation of Different Crop Roots Exudates to the Survival and Suppressive Effect of Stenotrophomonas maltophilia ( PD 4560), Biocontrol Agent of Bacterial Wilt of Potato
Author(s) -
Elhalag Kamel M.,
Emara Hassan M.,
Messiha Nevein A. S.,
Elhadad Safwat A.,
Abdallah Suzan A.
Publication year - 2015
Publication title -
journal of phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 60
eISSN - 1439-0434
pISSN - 0931-1785
DOI - 10.1111/jph.12381
Subject(s) - bacterial wilt , ralstonia solanacearum , biology , stenotrophomonas maltophilia , crop , rhizosphere , inoculation , horticulture , stenotrophomonas , biological pest control , agronomy , antagonism , biovar , bacteria , pathogen , microbiology and biotechnology , pseudomonas , pseudomonas aeruginosa , genetics , biochemistry , receptor
Experiments were performed under greenhouse conditions to control bacterial wilt of potato (potato brown rot), caused by Ralstonia solanacearum race 3 biovar 2, Phylotype II , sequevar 1 using various biocontrol strategies. These strategies involved the use of the bacterial biocontrol agent Stenotrophomonas maltophilia ( PD 4560), in clay or sandy soils, planted with cowpea, maize or tomato which was grown separately in different pots in the inoculated soils. After harvest, the soil derived from each cultivated crop was inoculated with a mixture of three virulent R. solanacearum strains (K3, K10 and K16) to achieve a final concentration of 5 × 10 8 cfu/g dry soil and used in pots under greenhouse conditions to cultivate potato seed tubers. The highest survival of S. maltophilia in soil (more than 160 days) coincided with a remarkable suppressing effect on disease incidence caused by R. solanacearum that expressed by wilt severity (up to 100% reduction), area under disease progress curve ( AUDPC ) (up to 99% reduction) and counts of the pathogen in soil (up to 75% reduction), rhizosphere (up to 80% reduction) and plant tissue (up to 97% reduction) of potato plants. The amino acid analysis of root exudates of crops under investigation revealed high percentages of asparagines (15.5–21%), glutamine (16–20%) and sulphur‐containing methionine (7–9%) in both of the cowpea and maize, respectively. In tomato root exudates, high percentages of arginine (around 26%) and lysine (around 23%) were detected. Methionine is known to favour the growth of S. maltophilia suggesting that especially cowpea and maize are suitable for crop rotation with potato and will enhance the sustainability of the biocontrol agent S. maltophilia .