Biotic and abiotic factors from soils have been implicated in the disease suppression of Rhizoctonia solani. This study included a Eucalyptus twig baiting assay, disease index and qPCR quantification of R. solani, and physicochemical analysis of 10 tobacco soils from five different locations (V: Vaqueros, C: Cerrillos, R: Rosario de Lerma, SA: San Agustín, CH: Chicoana) in the northwest of Argentina. Levels of Rhizoctonia soil inoculum quantified by baiting assay and qPCR were positively correlated. However, there was no correlation with root rot disease index in tobacco fields. Soils from V1, SA2 and CH2 fields, which reduced root rot disease on tobacco plants, were suppressive to R. solani infection. High clay, pH, organic matter content and physical stability in tobacco soils were the main physicochemical properties that limited Rhizoctonia development. Interestingly, growth of R. solani subgroups AG4‐HGI and AG4‐HGIII was highly suppressed in V1 and CH2 fields, and in SA2 fields, respectively. Undisturbed soil from a local forested mountain also resulted in reduction of growth of AG4‐HGIII and AG4‐HGI, while AG2‐1 was less affected, suggesting that high soil organic matter contributed to suppression of R. solani. Soils highly suppressive of R. solani had significantly different populations of culturable bacteria, Pseudomonas and fungi, but populations of actinobacteria and Trichoderma spp. did not differ. These different populations may be involved in the inhibition of fungal growth. The results demonstrated that physicochemical and biological properties of soil suppressive to R. solani could act as an alternative for controlling Rhizoctonia diseases on tobacco.

中文翻译：

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与抑制阿根廷西北部烟草田上茄枯萎病有关的土壤特性

土壤中的生物和非生物因素参与了茄根霉的病害抑制。这项研究包括桉树诱饵试验，茄红菌的疾病指数和qPCR定量分析，以及来自五个不同地点的10种烟草土壤的理化分析（V：Vaqueros，C：Cerrillos，R：Rosario de Lerma，SA：SanAgustín， CH：Chicoana）位于阿根廷西北部。水平丝核菌土接种定量通过引诱法和qPCR呈正相关。然而，与烟草田根腐病指数没有相关性。V1，SA2和CH2田地的土壤减少了烟草植株的根腐病，可抑制茄R感染。烟草土壤中的高粘土，pH，有机质含量和物理稳定性是限制根瘤菌生长的主要理化特性。有趣的是，在V1和CH2田地以及SA2田地中，茄尼罗非鱼亚群AG4-HGI和AG4-HGIII的生长被高度抑制。本地森林山区未受干扰的土壤也导致AG4-HGIII和AG4-HGI的生长减少，而AG2-1受到的影响较小，这表明较高的土壤有机质有助于抑制茄.。高度抑制茄念珠菌的土壤中可培养细菌，假单胞菌和真菌的种群明显不同，但放线菌和木霉属。没有不同。这些不同的种群可能参与真菌生长的抑制。结果表明，土壤中的茄枯萎菌的理化和生物学特性可以作为控制烟草上的Rhizoctonia疾病的替代方法。