Use of avirulent mutants of Pseudomonas solanacearum for the biological control of bacterial wilt of tomato plants

1990 ◽  
Vol 36 (1) ◽  
pp. 27-38 ◽  
Author(s):  
A. Trigalet ◽  
D. Trigalet-Demery
2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Putri Wulan Cahyani ◽  
Noor Laili Aziza ◽  
Yusriadi Marsuni

Cultivation of tomato plants (Lycopesicum esculentum Mill.) Is often exposed to plant diseases. One of the diseases that often attacks tomato plants is bacterial wilt disease caused by R. solanacearum. Therefore, it is necessary to have biological control with the application of an antagonistic agent, namely the provision of endophytic fungi from dayak onion flowers. This study aims to determine the types of endophytic fungi in dayak onion flowers and to determine the potential of endophytic fungi in suppressing the growth of R. solanacearum. This research was conducted from February to May 2020, taking samples of dayak onion flowers in the Experimental Field of the Faculty of Agriculture and samples of symptomatic tomato plants on the Karang Anyar Farmer Group's land then continued with isolation, purification, identification, and antagonistic testing at the Production Laboratory of the Faculty of Agriculture, Lambung Mangkurat University, Banjarbaru. The method used in this study was a one-factor completely randomized design (CRD) with nine treatments, namely C1 = endophytic fungi A + R. solanacearum, C2 = endophytic fungi B + R. solanacearum, C3 = endophytic fungi F + R. solanacearum, C4 = endophytic fungi G + R. solanacearum, C5 = endophytic fungi I + R. solanacearum, C6 = endophytic fungi J + R. solanacearum, C7 = endophytic fungi K + R. solanacearum, C8 = fungi endophytic N + R. solanacearum, and C9 = endophytic fungi P + R. solanacearum and repeated three times. This study used a comparison, namely control with three replications, in order to obtain 30 experimental units. The results of this study that endophytic fungi from dayak onion flowers have the potential to suppress the growth of R. solanacearum. Based on the research, there were 17 endophytic fungi from dayak onion flowers with nine endophytic fungi which had the fastest growth rate of radius. Fungi with the genus Colletotrichum sp., Mucor sp., and Papulaspora sp. has the potential to suppress the growth of R. solanacearum with moderate to strong percentage of inhibition.


2001 ◽  
Vol 183 (12) ◽  
pp. 3597-3605 ◽  
Author(s):  
Julie Tans-Kersten ◽  
Huayu Huang ◽  
Caitilyn Allen

ABSTRACT Ralstonia solanacearum, a widely distributed and economically important plant pathogen, invades the roots of diverse plant hosts from the soil and aggressively colonizes the xylem vessels, causing a lethal wilting known as bacterial wilt disease. By examining bacteria from the xylem vessels of infected plants, we found thatR. solanacearum is essentially nonmotile in planta, although it can be highly motile in culture. To determine the role of pathogen motility in this disease, we cloned, characterized, and mutated two genes in the R. solanacearum flagellar biosynthetic pathway. The genes for flagellin, the subunit of the flagellar filament (fliC), and for the flagellar motor switch protein (fliM) were isolated based on their resemblance to these proteins in other bacteria. As is typical for flagellins, the predicted FliC protein had well-conserved N- and C-terminal regions, separated by a divergent central domain. The predicted R. solanacearum FliM closely resembled motor switch proteins from other proteobacteria. Chromosomal mutants lackingfliC or fliM were created by replacing the genes with marked interrupted constructs. Since fliM is embedded in the fliLMNOPQR operon, the aphAcassette was used to make a nonpolar fliM mutation. Both mutants were completely nonmotile on soft agar plates, in minimal broth, and in tomato plants. The fliC mutant lacked flagella altogether; moreover, sheared-cell protein preparations from the fliC mutant lacked a 30-kDa band corresponding to flagellin. The fliM mutant was usually aflagellate, but about 10% of cells had abnormal truncated flagella. In a biologically representative soil-soak inoculation virulence assay, both nonmotile mutants were significantly reduced in the ability to cause disease on tomato plants. However, the fliC mutant had wild-type virulence when it was inoculated directly onto cut tomato petioles, an inoculation method that did not require bacteria to enter the intact host from the soil. These results suggest that swimming motility makes its most important contribution to bacterial wilt virulence in the early stages of host plant invasion and colonization.


2021 ◽  
Author(s):  
Xiaoyan Yu ◽  
Xue Zhang ◽  
Jing Zhang ◽  
Lida Zhang ◽  
Yanjie Jiao ◽  
...  

2008 ◽  
Vol 69 (1) ◽  
pp. 125-134 ◽  
Author(s):  
Czesław Ślusarski

Attempts at Biological Control ofClavibacter michiganensissubsp.michiganensisOn Rockwool-Grown Greenhouse TomatoesTwo greenhouse experiments were conducted in which tomato plants artificially inoculated withClavibacter michiganensissubsp.michiganensis(Cmm) were grown in an open rockwool system as spring and autumn crops. Two isolates of the rhizosphere bacteria,Pseudomonas fluorescensstrain PSR21,Pseudomonas reactansstrain GGS14, a commercial biocontrol agent Aqua Bac Plus (Bacillusspp.) and a proprietary disinfectant containing QAC+Chx, applied at weekly intervals, were evaluated for their efficiency in the suppression of the bacterial canker of tomato. All treatments tested revealed to be ineffective in controlling the disease. The introduction ofCmmbacteria into the fresh rockwool in the first year of its usage resulted in a 100% death of tomato plants, whereas following an artificial inoculation of two- and three-year-old rockwool slabs withCmmbacteria dead plants amounted to 70 and 58%, respectively. This indicates that in the re-used rockwool a natural microbial suppressiveness to bacterial canker of tomato might be developed in the root zone.


2021 ◽  
Author(s):  
April M MacIntyre ◽  
Valerian Meline ◽  
Zachary Gorman ◽  
Steven P Augustine ◽  
Carolyn J Dye ◽  
...  

Ralstonia solanacearum causes plant bacterial wilt disease, leading to severe crop losses. Xylem sap from R. solanacearum-infected tomato is enriched in host produced trehalose. Water stressed plants accumulate the disaccharide trehalose, which increases drought tolerance via abscisic acid (ABA) signaling networks. Because infected plants have reduced water flow, we hypothesized that bacterial wilt physiologically mimics drought stress, which trehalose could mitigate. Transcriptomic responses of susceptible vs. resistant tomato plants to R. solanacearum infection revealed differential expression of drought-associated genes, including those involved in ABA and trehalose metabolism. ABA was enriched in xylem sap from R. solanacearum-infected plants. Treating roots with ABA lowered stomatal conductance and reduced R. solanacearum stem colonization. Treating roots with trehalose increased ABA in xylem sap and reduced plant water use by reducing stomatal conductance and temporarily improving water use efficiency. Further, trehalose-treated plants were more resistant to bacterial wilt disease. Trehalose treatment also upregulated expression of salicylic acid (SA)-dependent defense genes, increased xylem sap levels of SA and other antimicrobial compounds, and increased wilt resistance of SA-insensitive NahG tomato plants. Additionally, trehalose treatment increased xylem concentrations of jasmonic acid and related oxylipins. Together, these data show that exogenous trehalose reduced both water stress and bacterial wilt disease and triggered systemic resistance. This suite of responses revealed unexpected linkages between plant responses to biotic and abiotic stress and suggests that that R. solanacearum-infected tomato plants produce more trehalose to improve water use efficiency and increase wilt disease resistance. In turn, R. solanacearum degrades trehalose as a counter-defense.


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