Control of Polymyxa betae by Bacillus amyloliquefaciens lipopeptides
(2011) International Working group on Plant Viruses with Fungal vectors — Location: Louvain-la-Neuve (6.July.2011)
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- Abstract
- Rhizomania is one of the most important diseases of sugar beet. It is caused by Beet necrotic yellow vein virus (BNYVV), which is transmitted by the protist Polymyxa betae. Until now, only a few resistance genes against BNYVV have been used in the control of the disease. Within the context of integrated pest management, the effect of molecules stimulating the host defence mechanism in P. betae infection was explored. Systemic acquired resistance (SAR) was induced by spraying the leaves with a synthetic analog of salicylic acid three times before inoculation with P. betae zoospores. Also before inoculation, induced systemic resistance (ISR) was elicited twice, with a 1-week interval, by watering the sugar beet roots with a Bacillus amyloliquefaciens lipopeptides solution. One week after inoculation, the plants were harvested and P. betae was quantified in the roots using a quantitative PCR assay. The ISR was controlled by assessing the expression of the NPR1 gene and three PR genes. Both systemic resistances were induced in corresponding treated plants (SAR-salicylic acid analog; ISR-lipopeptides). Although no reduction in P. betae infection was observed in SAR-induced plants, P. betae infection decreased significantly for the two concentrations of zoospores from 10 times (5000 zoospores) to 16 times (500 zoospores) when the plants were treated with the bacterial lipopeptides. These results accord with the fact that P. betae induced the SAR. It therefore seems to be insensitive to the defences induced by SAR but not to those by ISR. This decrease in infection, due to ISR, might affect viral transmission and hence rhizomania pressure in fields. From an integrated pest management perspective, the decrease in disease pressure due to bacterial lipopeptides could help to preserve genetic resistance to the virus longer and provide a new way to manage P. betae inoculum potential in soils.
- Affiliations
Gembloux ABT, ULg CWBI
Citations
Desoignies, N., Schramme, F., Ongena, M., & Legrève, A. (2011). Control of Polymyxa betae by Bacillus amyloliquefaciens lipopeptides. In Ed. U. Merz (ed.), Proceedings of the Eigth Symposium of the International Working Group on Plant Viruses with Fungal Vectors (pp. 59-62). https://hdl.handle.net/2078.5/206048