Strategies to Improve Biological Control of Soilborne Plant Diseases

Biological control of plant soilborne diseases has appeared as an attractive alternative to other control methods. For the biological control of plant soilborne diseases, microorganisms mainly bacteria and fungi are used, which suppress growth and virulence traits or even kill pathogens and induce plant systemic acquired resistance. In recent years, the demand for organic food increased the use of biological control agents; however, complete control of plant diseases has not been achieved yet. The beneficial microbes used for biological control of plant diseases perform admirably under controlled greenhouse conditions but are not always successful under field conditions, which highly discourages the biological control methods. Hence, complete removal of chemicals from agricultural systems may not be impossible but a logical reduction in their application is feasible. Therefore, systematic integrated methods including both chemical and biological control and other control methods like cultural practices, resistant varieties and crop rotation are highly recommended.

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Cross-Protection and Systemic Acquired Resistance for Control of Plant Diseases

Handbook of Biological Control ◽

10.1016/b978-012257305-7/50066-7 ◽

1999 ◽

pp. 549-556 ◽

Cited By ~ 2

Author(s):

J. ALLAN DODDS

Keyword(s):

Systemic Acquired Resistance ◽

Acquired Resistance ◽

Cross Protection ◽

Plant Diseases

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487 Assessment of Chemical Induction of Acquired Resistance to Phytophthora Fruit Rot in Field-grown Pickling Cucumber

HortScience ◽

10.21273/hortsci.34.3.529a ◽

1999 ◽

Vol 34 (3) ◽

pp. 529A-529

Author(s):

Priscilla M. Hockin ◽

Irvin E. Widders

Keyword(s):

Systemic Acquired Resistance ◽

Phytophthora Capsici ◽

Acquired Resistance ◽

Lesion Size ◽

Plant Diseases ◽

Fruit Rot ◽

Chemical Induction ◽

Resistance Response ◽

Chemical Inducers ◽

Cucumber Fruit

Systemic acquired resistance (SAR) is a physiological defense response in plants conferring broad spectrum resistance to pathogens. SAR is inducible through infection by necrotizing pathogens or chemical inducers and involves the systemic activation of defense related genes. Our objectives were to evaluate resistance expression to phytophthora soft rot fruit in cucumber in response to increasing concentrations of 2,6 dichloroisonicotinic acid (INA) and benzo (1,2,3)thiadiazole-7-carbothioc acid S-methyl ester (BTH) by foliar applications. Excised leaves exhibited a resistance response to foliar applications of all concentrations of INA and BTH tested when challenge inoculated with Colletotrichum lagenarium. There was increasing benefit with increasing concentration of each chemical applied. Harvested cucumber fruit, 3.4 to 4.5 cm in diameter, were challenge inoculated with Phytophthora capsici; there were no significant chemical and rate interactions in terms of internal lesion measurements. Overall, INA consistently reduced lesion size in cucumber fruit. A bioassay conducted on fruit of different maturity levels, as defined by fruit diameter, revealed that larger sized fruit (4 to 5 cm) were more resistant to fruit rot. Fruit with diameters of 3 to 4 cm from plots treated with BTH showed little resistance as compared to the control and fruit from the same treatment with diameters of 2 to 3 cm. Fruit from plots treated with INA had at least 50% reduction in lesion size than the control. It is unclear if these differences were attributable to changes in physiological or anatomical factors. The true importance of these results should be interpreted with caution. Yield studies have not been conducted, and thus, with the experienced stunting, treatment with 100 ppm INA would be expected to lower yield and perhaps fruit quality. Determination of the optimal application regime and other cultural factors will provide broad control of plant diseases.

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Screening for the identification of potential biological control agents that induce systemic acquired resistance in sugar beet

Biological Control ◽

10.1016/j.biocontrol.2003.11.005 ◽

2004 ◽

Vol 30 (2) ◽

pp. 342-350 ◽

Cited By ~ 66

Author(s):

R.L. Bargabus ◽

N.K. Zidack ◽

J.E. Sherwood ◽

B.J. Jacobsen

Keyword(s):

Biological Control ◽

Sugar Beet ◽

Systemic Acquired Resistance ◽

Acquired Resistance ◽

Biological Control Agents

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Recombinant Protein Foliar Application Activates Systemic Acquired Resistance and Increases Tolerance against Papaya Dieback Disease

Asian Journal of Agriculture and Rural Development ◽

10.18488/journal.ajard.2021.111.1.9 ◽

2021 ◽

Vol 11 (1) ◽

pp. 1-9

Author(s):

Norliza Abu-Bakar ◽

Nor Mustaiqazah Juri ◽

Ros Azrinawati Hana Abu-Bakar ◽

Mohd Zulfadli Sohaime ◽

Rafidah Badrun ◽

...

Keyword(s):

Recombinant Protein ◽

Systemic Acquired Resistance ◽

Foliar Application ◽

Acquired Resistance ◽

Plant Diseases ◽

Immune Memory ◽

Pcr Analysis ◽

Pr Genes ◽

Defense Gene Expression ◽

Dieback Disease

Similar to animals, plants possess ‘immune memory’ in response to invading pathogens that lead to enhanced defense reaction following pathogen exposure. Systemic acquired resistance (SAR) is a well-characterized type of plant immunity and is associated with coordinated expression of a set of pathogenesis-related (PR) genes and proteins also known as SAR markers. Induction of SAR in plants was shown to be initiated by group of chemicals and biological compounds known as SAR inducers that can be used for the management of important plant diseases. Elucidation and characterization of potential SAR inducers as potential elicitors that can protect papaya from the papaya dieback disease pathogen were carried out using HRPX protein, which was produced as a recombinant protein in an Escherichia coli system. Disease severity analysis in a glasshouse experiment indicated lower disease infection rates in the HRPX-treated plants than in water-treated plants. Selected SAR-associated defense gene expression was also shown to increase in treated plants, via quantitative real-time PCR analysis, confirming enhanced disease response through SAR activation. In this report, the selected recombinant protein was shown to activate the SAR mechanism in papaya for increased tolerance against papaya dieback disease, which was proven via physiological and molecular analysis.

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Practical application of induced resistance to plant diseases: an appraisal of effectiveness under field conditions

The Journal of Agricultural Science ◽

10.1017/s0021859609008806 ◽

2009 ◽

Vol 147 (5) ◽

pp. 523-535 ◽

Cited By ~ 86

Author(s):

D. R. WALTERS ◽

J. M. FOUNTAINE

Keyword(s):

Induced Resistance ◽

Systemic Acquired Resistance ◽

Regulatory Protein ◽

Acquired Resistance ◽

Crop Protection ◽

Plant Growth Promoting Rhizobacteria ◽

Plant Diseases ◽

Systemic Resistance ◽

Plant Parts ◽

The Impact

SUMMARYPlants resist pathogen attack through a combination of constitutive and inducible defences. Different types of induced resistance have been defined based on differences in signalling pathways and spectra of effectiveness. Systemic acquired resistance (SAR) occurs in distal plant parts following localized infection by a necrotizing pathogen. It is controlled by a signalling pathway that depends upon the accumulation of salicylic acid (SA) and the regulatory protein NPR1. In contrast, induced systemic resistance (ISR) is promoted by selected strains of non-pathogenic plant growth-promoting rhizobacteria (PGPR). ISR functions independently of SA, but requires NPR1 and is regulated by jasmonic acid (JA) and ethylene (ET).Resistance can be induced by treatment with a variety of biotic and abiotic inducers. The resistance induced is broad spectrum and can be long-lasting, but is rarely complete, with most inducing agents providing between 0·20 and 0·85 disease control. In the field, expression of induced resistance is likely to be influenced by the environment, genotype, crop nutrition and the extent to which plants are already induced. Unfortunately, understanding of the impact of these influences on the expression of induced resistance is rudimentary. So too is understanding of how best to use induced resistance in practical crop protection. This situation will need to change if induced resistance is to fulfil its potential in crop protection.

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EVALUATION OF BIOLOGICAL CONTROL AGENTS, SYSTEMIC ACQUIRED RESISTANCE INDUCERS AND BACTERICIDES FOR THE CONTROL OF FIRE BLIGHT ON APPLE BLOSSOM

Acta Horticulturae ◽

10.17660/actahortic.1999.489.96 ◽

1999 ◽

pp. 553-558 ◽

Cited By ~ 9

Author(s):

M.T. Momol ◽

J.L. Norelli ◽

H.S. Aldwinckle

Keyword(s):

Biological Control ◽

Fire Blight ◽

Systemic Acquired Resistance ◽

Acquired Resistance ◽

Biological Control Agents ◽

Resistance Inducers

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Effect of Application Frequency and Reduced Rates of Acibenzolar-S-Methyl on the Field Efficacy of Induced Resistance Against Bacterial Spot on Tomato

Plant Disease ◽

10.1094/pdis-03-11-0183 ◽

2012 ◽

Vol 96 (2) ◽

pp. 221-227 ◽

Cited By ~ 46

Author(s):

Cheng-Hua Huang ◽

Gary E. Vallad ◽

Shouan Zhang ◽

Amin Wen ◽

Botond Balogh ◽

...

Keyword(s):

Disease Severity ◽

Untreated Control ◽

Systemic Acquired Resistance ◽

Field Experiments ◽

Acquired Resistance ◽

Foliar Spray ◽

Field Trials ◽

Plant Diseases ◽

Bacterial Spot ◽

Field Efficacy

Acibenzolar-S-methyl (ASM), a plant activator known to induce systemic acquired resistance, has demonstrated an ability to manage a number of plant diseases, including bacterial spot on tomato caused by four distinct Xanthomonas spp. The aim of this study was to evaluate application rate and frequency of ASM in order to optimize field efficacy against bacterial spot in Florida, while minimizing its impact on marketable yields. ASM was applied biweekly (once every 2 weeks) as a foliar spray at a constant concentration of 12.9, 64.5, and 129 μM throughout four field experiments during 2007–08. A standard copper program and an untreated control were also included. Overall, biweekly applications of ASM did not significantly reduce disease development or the final disease severity of bacterial spot compared with the copper-mancozeb standard or the untreated control. Only one experiment showed a significant reduction in the final disease severity on plants treated with ASM at 129 μM compared with the untreated control. Three additional field trials conducted during 2009–10 to evaluate the effects of weekly and biweekly applications of ASM at concentrations of 30.3 to 200 μM found that weekly applications provided significantly better disease control than biweekly applications. The tomato yields were not statistically improved with the use of ASM relative to the untreated control and standard copper program. Weekly ASM applications at rates as low as 75 μM (equivalent to 1.58 g a.i./ha in 100 liters of water or 0.21 oz. a.i./acre in 100 gallons of water) to 200 μM (equivalent to 4.20 g a.i./ha in 100 liters of water or 0.56 oz. a.i./acre in 100 gallons of water) were statistically equivalent in managing bacterial spot of tomato without significantly reducing yield compared with the untreated control.

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