Biotic changes in relation to local decrease in soil conduciveness to disease caused by Rhizoctonia solani

Abstract

The relationships between biotic changes and local decrease in soil conduciveness in disease patches towards the disease incited by Rhizoctonia solani AG 2-2 in a sugar beet field in France were investigated. Soil samples from healthy and diseased areas were analysed for bacterial and fungal densities, molecular and physiological microbial community structures, and antagonistic abilities of Trichoderma isolates collected from diseased and healthy areas. Although the inoculum density was higher inside the disease patches, the respective soil was less conducive towards disease incited by R. solani AG 2-2. It was concluded that the pathogen was present in healthy areas but did not incite disease in field conditions. Conversely, the response of the microflora to previous development of R. solani in diseased areas prevented further pathogenic activity. Indeed, genetic and physiological structures of the fungal communities and physiological structures of the bacterial communities were modified in disease patches compared to healthy areas. The terminal restriction fragment length polymorphism (T-RFLP) analysis revealed that the peaks corresponding to R. solani and Trichoderma spp. were higher inside the patches than in the healthy areas. Trichoderma isolates from the disease patches were more antagonistic than those from the healthy areas. These results suggest that disease caused by R. solani AG 2-2 induced changes in genetic and physiological structure of microbial populations and development of antagonists. The decreased conduciveness inside the patches may help explain patch mobility in the following season.

RETRACTED: Soil Microbiome Manipulation Gives New Insights in Plant Disease-Suppressive Soils from the Perspective of a Circular Economy: A Critical Review

“…Therefore, attempts have been made to differentiate the microbial community composition and structure in the DSS from the DCS [77]. Microbiota change in relation to a local decrease in conduciveness to damping-off and other diseases caused by R. solani [78]. Maintaining dynamic microbial balance among C T E D the species, high microbial biomass and high biodiversity are key factors that can facilitate the development of DSS [79][80][81].…”

The Effect of Biostimulants on the Health Status and Content of Chlorogenic Acids in Potato Tubers (Solanum Tuberosum L.) with Colored Flesh

“…The above observations contradict the results of published studies where Trichoderma spp. species were more effective antagonists of R. solani in infected than in healthy potatoes (Anees et al 2010), and in soils with a higher abundance of sclerotia (Grosch et al 2006). In potatoes cvs.…”

Soil-plant-microbiota interactions to enhance plant growth

“…Biological control is an indirect mechanism of plant growth promotion since it involves the release of bioactive molecules by PGPM, which minimize or cease the harmful effects of phytopathogens, instead of directly improving plant growth (Datta and Chakrabartty, 2014;Vargas et al, 2017;Volpiano et al, 2018). At the same time, every soil has some level of resistance against plant diseases (Anees et al, 2010). This ability of a soil to avoid the onset of a disease in a susceptible plant host, even in the presence of a significant inoculum density of the pathogen, is called soil suppressiveness (Klein et al, 2011).…”