Curtin University researchers have discovered some agricultural soils can naturally suppress one of Australia\u2019s most damaging broadacre crop diseases.<\/p>\n\n\n\n
The research, published in the international journal Applied Soil Ecology<\/em>, found some soils can inhibit infection and survival of Sclerotinia sclerotiorum<\/em> \u2014 the fungus responsible for Sclerotinia stem rot, a disease that causes significant yield losses in broadacre crops such as canola and pulses.<\/p>\n\n\n\n Lead author Dr Viet-Cuong Han<\/a>, from the Centre for Crop and Disease Management<\/a>, said the study highlights the role of soil as a living biological system, rather than a passive growing medium.<\/p>\n\n\n\n \u201cWe identified a soil that naturally suppresses Sclerotinia sclerotiorum<\/em> by preventing the fungus from infecting plants and by inhibiting germination of its survival structures in the soil,\u201d Dr Han said.<\/p>\n\n\n\n \u201cIn field conditions, by comparing a suppressive soil with a nearby disease-conducive soil, we found clear differences in microbial community structure. Suppressive soils were enriched with well-known naturally occurring biocontrol organisms, particularly bacteria from the genera Bacillus<\/em> and Streptomyces<\/em>.<\/p>\n\n\n\n \u201cThese microbes actively \u2018antagonise\u2019 the pathogen.<\/p>\n\n\n\n \u201cThis suppressive effect is driven by the soil microbiome \u2014 the community of microscopic organisms living in the soil \u2014 and under controlled and experimental conditions the effect can be expressed in soils that are normally conducive to disease, by inoculating the conducive soil with the microbiome from the suppressive soil.\u201d<\/p>\n\n\n\n Dr Han said the research showed that Bacillus<\/em> bacteria are central to disease-suppressing soils, while both Bacillus<\/em> and Streptomyces<\/em> help stop fungal growth and reduce disease in lab and plant tests.<\/p>\n\n\n\n \u201cThe study also identified bacteria from Western Australian soils that had not previously been shown to fight Sclerotinia sclerotiorum<\/em>, suggesting that disease-suppressing soils could be a source of native microbes that may be helpful to control crop disease,\u201d Dr Han said.<\/p>\n\n\n\n \u201cWe also found certain soil properties were linked to disease suppression, with less acidic soils and those with lower carbon-to-nitrogen levels better able to suppress the pathogen.\u201d<\/p>\n\n\n\n