Plant Pathology and Crop Protection

Implementation of biological control strategies against soilborne pathogens in the farming industry: a seed to field approach (BioCon)

Partners:

  • Georg-August University of Göttingen, Department for Crop Sciences, Division of Plant Pathology and Crop Protection
  • Agricultural University of Athens, Plant Pathology Laboratory
  • KWS Saat AG
  • Spirou Group of Companies
Funded by:
Bundesministerium für Bildung und Forschung, General Secretariat for Research and Technology

Duration: April 2014 – March 2016

Project coordinator: Dr. Magdalena Siebold
Investigators (Göttingen): Asma Akter, Vera Kuhlmann, Dr. Jessica Knüfer, Dr. Daniel Lopisso

Objective

The main objective of this bilateral research project is the development of biological control strategies against soilborne pathogens applicable in commercial agricultural cropping systems in Greece and Germany.

Background

The problem: soilborne pathogens
The soilborne plant pathogens V. dahliae, V. longisporum and Fusarium oxysporum belong to the most destructive plant pathogens causing wilt and premature ripening in a wide range of economically important food and bioenergy crops worldwide. In Greece, Fusarium oxysporum f. sp. radicis cucumerinum (FORC) and Fusarium oxysporum f. sp. radicis lycopersici (FORL) cause ‘‘root and stem rot’’, resulting in significant yield losses in cucumber and tomato plants grown under greenhouse conditions (Vakalounakis and Fragkiadakis, 1999). V. dahliae is widespread in Greece, causing yield losses in a wide range of economically important plant species, particularly eggplant, one of the most susceptible hosts of the pathogen. In Germany, oilseed rape, the most important crop for edible oil, fodder and biofuel production suffers frequent yield losses due to premature ripening caused by V. longisporum (Dunker et al. 2008). In certain sugar beet cultivation areas, V. dahliae has been observed as a pathogen more frequenty in recent years (Heupel & Varrelmann 2010).
The pathogens are difficult to control due to the long viability of their resting structures in the soil and the inability of fungicides to affect the pathogens once they have entered the xylem vessels of the host via the roots. Due to the hidden life of these soilborne pathogens inside the soil and the host plant, management is only possible via chemical soil fumigation or resistant cultivars. However, the environmental problems associated with methyl bromide and its ban in the European Union since 2005 drastically limited the control strategies available for the farmers (Lopez-Escudero and Mercado-Blanco, 2011), and resistant cultivars are often not available. Hence, the development and use of alternative control methods, such as the use of biological control agents (BCAs) seems an appealing management strategy for both the conventional and organic farming industry.

The potential solution: BCA and compost release strategies:
Over the past 150 years, research repeatedly demonstrated that bacteria and fungi have an intimate interaction with their host plants and are able to promote plant growth as well as to suppress plant pathogens (Whipps 2001; Thakore 2006). The same disease suppressive phenomenon has been observed in soils following addition of certain composts in greenhouse production systems (Hoitink et al., 1997; Hoitink and Boehm, 1999). Composts have also been found effective as biocontrol agents under field conditions (Keener et al., 2000).
The biocontrol potential of a number of rhizobacteria and fungi existing ubiquitously in soils against V. dahliae and F. oxysporum has been studied previously (Antonopoulos et al. 2008, El-Hassan & Goven 2006, Gizi et al. 2011, Malandraki et al. 2008, Müller & Berg 2008) and some commercial products, mainly for application in small scale organic vegetable production, have been developed. However, no biological product for successful Verticillium control applicable in large scale agricultural production is available in Germany until now. Similarly, in Greece there is no commercial biocontrol product available in the market for use against V. dahliae or F. oxysporum.
Seed treatment is considered as an ideal method for introducing BCAs to control soilborne pathogens, because it allows the BCA to be placed where it is most needed, and the BCA’s growth can be supported by the plant it protects (El-Hassan & Gowen, 2006). Another BCA delivery concept is the one of introducing BCAs into the rhizosphere using the transplant soil plug. This strategy is based on the hypothesis that BCA establishment in the relatively clean environment of the planting media would provide an opportunity to develop stable populations in the seedling rhizosphere, and that these populations would then persist in the field. It has been also hypothesized that early exposure to BCAs might precondition young plants to resist pathogen attack after transplanting in the field (Kokalis-Burelle et al., 2006). A biocontrol strategy based on the application of BCAs as seed coating material would be the most advantageous in economic returns and agricultural practice strategy against soilborne pathogens in large-scale agricultural production. BCAs in the transplant soil plug to protect the plants in the field would be another promising control strategy for crops that are initially grown in the nursery and then transplanted in the field.

In this bilateral research project, the potential of the known V. dahliae antagonists Paenibacillus alvei K 165 and the non-pathogenic strains Fusarium oxysporum F2 (Tjamos et al., 2004; Malandraki et al., 2008) and V. tricorpus 1808 to control the pathogens V. longisporum and Fusarium sp. with a life cycle similar to V. dahliae will be investigated.

References

  • Antonopoulos DF, Tjamos SE, Antoniou PP, Rafeletos P, Tjamos EC, (2008). Effect of Paenibacillus alvei, strain K165, on the germination of Verticillium dahliae microsclerotia in planta. Biological Control 46: 166-70
  • Dunker S, Keunecke H, Steinbach P, von Tiedemann A. (2008). Impact of Verticillium longisporum on yield and morphology of winter oilseed rape (Brassica napus) in relation to systemic spread in the plant. Journal of Phytopathology 156, 698-707
  • El-Hassan SA, Gowen SR, (2006) Formulation and delivery of the bacterial antagonist Bacillus subtilis for management of lentil vascular wilt caused by Fusarium oxysporum f. sp. lentis. Journal of Phytopathology 154: 148-55.
  • Gizi D, Stringlis I, Tjamos SE, Paplomatas EJ, (2011). Seedling vaccination by stem injecting a conidial suspension of F2, a non-pathogenic Fusarium oxysporum strain, suppresses Verticillium wilt of eggplant. Biological Control 58: 387-392
  • Heupel M, Varrelmann M (2010): Verticillium dahliae - symptoms in sugarbeet, Julius-Kühn- Archiv 2010 No. 428 pp. 155-156
  • Hoitink HAJ, Stone AG, Han DY, (1997) Suppression of plant disease by composts. Horticulture Science 32: 184–187
  • Hoitink HAJ, Boehm MJ, (1999) Biocontrol within the context of soil microbial communities: A substrate-dependent phenomenon. Annual Review of Phytopathology 37: 427-446
  • Keener HM, Dick WA, Hoitink HAJ, (2000) Composting and beneficial utilization of composted by-product materials. Chapter 10. pp. 315-341. In: J.F. Power et al. (eds.) Beneficial uses of agricultural, industrial and municipal by-products. Soil Science Society of America. Madison, Wisconsin.
  • Kokalis-Burelle N, Kloepper JW, Reddy MS, (2006) Plant growth-promoting rhizobacteria as transplant amendments and their effects on indigenous rhizosphere microorganisms. Applied Soil Ecology 31: 91-100
  • López-Escudero, F.J., and Mercado-Blanco, J. (2011) Verticillium wilt of olive: a case study to implement an integrated strategy to control a soil-borne pathogen. Plant Soil 344: 1–50
  • Malandraki I, Tjamos SE, Pantelides I, Paplomatas EJ, (2008) Thermal inactivation of compost suppressiveness implicates possible biological factors in disease management. Biological Control 44: 180-187
  • Müller H, Berg G, (2008) Impact of formulation procedures on the effect of the biocontrol agent Serratia plymuthica HRO-C48 on Verticillium wilt in oilseed rape. BioControl 53: 905-916
  • Thakore Y (2006) The biopesticide market for global agricultural use. Industrial Biotechnology 2: 194–208
  • Tjamos EC, Tsitsigiannis DI, Tjamos SE, Antoniou PP, Katinakis P, (2004) Selection and screening of endorhizosphere bacteria from solarized soils as biocontrol agents against Verticillium dahliae of solanaceous hosts. European Journal of Plant Pathology 110: 35-44
  • Vakalounakis DJ, Fragkiadakis GA, (1999) Genetic diversity of Fusarium oxysporum isolates from cucumber: differentiation by pathogenicity, vegetative compatibility and RAPD fingerprinting. Phytopathology 89: 161–168
  • Whipps J, (2001) Microbial interactions and biocontrol in thrhizosphere. Journal of Experimental Botany 52: 487–511