Root-knot nematode infections and soil characteristics significantly affected microbial community composition and assembly of tobacco soil microbiota: a large-scale comparison in tobacco-growing areas

Abstract

IntroductionTobacco root-knot nematode (RKN) is a highly destructive soil-borne disease worldwide. However, there is a lack of research on the relationship between RKN and tobacco root microbial community composition under large-scale geographical conditions in China.MethodsIn this study, we collected 65 samples from 28 main tobacco-growing areas across 10 provinces in China and conducted 16S rDNA sequencing to investigate the dynamic microbial changes in tobacco soil infected by RKN compared to healthy tobacco soil. Based on the analysis of rhizosphere soil bacterial communities, changes after RKN infection, and soil environmental factors.ResultsWe found the 28 tobacco-growing areas could be divided into two distinct groups with different microbial compositions and varying responses to RKN infection. In group1 of the provinces of Anhui, Henan, Shanxi, and Heilongjiang, Vicinamibacteria dominated the bacterial community, while Acidobacteriae was present in low abundance. In contrast, group2 of the other six provinces (Yunnan, Guizhou, Chongqing, Guangxi, Hubei, and Shandong) exhibited an opposite pattern. After infected by RKN, the genera Chitinophaga increased significant in group 1, while the genera Rhodococcus in group 2 exhibited a substantial increase. Alpha-diversity analysis revealed that RKN-infected tobacco exhibited a richer and more diverse rhizosphere soil bacterial community compared to healthy tobacco in most growing areas. A total of 12 kinds of soil environmental factors were measured in healthy and RKN-infected tobacco soil, and based on the co-occurrence and correlation analysis between environmental factors and microbial species, the pH level, calcium (Ca), magnesium (Mg), phosphorus (P), iron (Fe), and sodium (Na) were identified as key environmental factors influencing the population composition of rhizosphere microorganisms during RKN infection. We observed that RKN infection further increased the pH in weakly alkaline group 1 soil, while weakly acidic group 2 soil experienced a further decrease in pH. Furthermore, we identified three genera as potential biocontrol or plant growth-promoting bacteria for tobacco.DiscussionThese findings provide valuable reference data for managing RKN disease in different tobacco-growing areas and contribute to the exploration of new and effective biological control methods.

Understanding the dynamic interactions of root-knot nematodes and their host: role of plant growth promoting bacteria and abiotic factors

“…The obvious below-ground symptom of RKN infection is the formation of galls on the roots that reduce the absorption and translocation of water and dissolved nutrients. RKN root damage also fosters access to secondary infection of roots by soil pathogens such as fungi and bacteria ( Agrios, 2005 ; Cao et al., 2023 ). Because of their wide host range and distribution, effective RKN management is becoming a global priority.…”

“…Some reasons for that are the weak competitive ability of the microbial agents and the failure to establish a high density in soil ecosystems. In soil ecosystems, host-RKN interactions are complex and can be affected by different soil physicochemical and biological properties ( Cao et al., 2023 ). Soil physicochemical and biological properties modulate host-RKN interactions, and they are in turn affected by different agricultural practices.…”

Integrated metabolomic and metagenomic strategies shed light on interactions among planting environments, rhizosphere microbiota, and metabolites of tobacco in Yunnan, China

“…Moreover, about half of tobacco produced in China is planted in Yunnan, and planting and harvesting of tobacco leaves have been the major source of income for millions of farmers, especially in poor areas of Yunnan ( Teh-wei et al, 2010 ). To understand the interaction among the rhizosphere bacteriomes of tobacco, Cao et al (2023) conducted amplicon sequencing of 16S rDNA to investigate the dynamic changes in soil bacteria between the healthy and root-knot nematode-infected tobacco plants, with similar strategies. Zhou et al (2023) studied different intercropping system-modulated soil–bacterial communities that shaped the growth and development status of tobacco.…”