Tobacco Root Microbial Community Composition Significantly Associated With Root-Knot Nematode Infections: Dynamic Changes in Microbiota and Growth Stage

Abstract

The root-knot nematode (RKN) is an important pathogen that affects the growth of many crops. Exploring the interaction of biocontrol bacteria-pathogens-host root microbes is the theoretical basis for improving colonization and controlling the effect of biocontrol bacteria in the rhizosphere. Therefore, 16S and 18S rRNA sequencing technology was used to explore the microbial composition and diversity of tobacco roots (rhizosphere and endophytic) at different growth stages in typical tobacco RKN-infected areas for 2 consecutive years. We observed that RKN infection changed the α-diversity and microbial composition of root microorganisms and drove the transformation of microorganisms from bacteria to fungi. The abundance of Sphingomonas decreased significantly from 18% to less than 3%, while the abundance of Rhizobiaceae increased from 4 to 15% at the early growth stage during the first planting year, and it promoted the proliferation of Chryseobacterium at the late growth stage in rhizosphere microorganisms with the highest abundance of 17%. The overall trend of rhizosphere microorganisms changed in the early growth stage with increasing growth time. The specific results were as follows: (1) Rhizobiaceae and Chryseobacterium increased rapidly after 75 days, became the main abundant bacteria in the rhizosphere microorganisms. (2) The dominant flora in fungi were Fusarium and Setophoma. (3) Comparing the root microbes in 2017 and 2018, RKN infection significantly promoted the proliferation of Pseudomonas and Setophoma in both the rhizosphere and endophytes during the second year of continuous tobacco planting, increasing the relative abundance of Pseudomonas from 2 to 25%. Pseudomonas was determined to play an important role in plant pest control. Finally, a total of 32 strains of growth-promoting bacteria were screened from tobacco rhizosphere bacteria infected with RKN through a combination of 16S rRNA sequencing and life-promoting tests. The results of this research are helpful for analyzing the relationship between RKNs and bacteria in plants, providing reference data for elucidating the pathogenesis of RKNs and new ideas for the biological control of RKNs.

Plant G x Microbial E: Plant genotype interaction with soil bacterial community shapes rhizosphere composition during invasion

“…The Micropepsaceae has been found to be an indicator taxon associated with specific plant species or site conditions in other studies (D. Wu et al 2023;Gschwend et al 2022). For studies that compared different environmental manipulations, the family was associated with early phases of restoration (grasslands; (Barber et al 2023)), early responses to agricultural planting (tobacco; (Cao et al 2022)), and response to cold treatments of plants (lettuce; (Persyn et al 2022)), all conditions in which a system had been perturbed recently. In one study, the presence of Micropepsaceae was also associated with reduced suppression of pathogens .…”

Endophytic fungi of Panax sokpayensis produce bioactive ginsenoside Compound K in flask fermentation

“…However, the members of Phaeosphaeriaceae, particularly Setophoma spp. have been reported as an endophyte of Panax ginseng and several other plants 50 – 52 .…”

Microbial landscapes of the rhizosphere soils and roots of Luffa cylindrica plant associated with Meloidogyne incognita

“…RKNs significantly affect the rhizosphere soil and root-endophytic microbial communities of the host plant ( Tian et al, 2015 ; Wolfgang et al, 2019 ; Zhou et al, 2019 ; Cao et al, 2022 ). Meanwhile, the microorganisms would produce secondary metabolites to affect the RKNs infection.…”

“…RKN infection of plants leads to physiological changes in the host and affects the composition of root exudates ( Tian et al, 2015 ). Some of these root exudates can directly antagonize disease and insect pests, while others can collect and select microbial flora conducive to plant growth under the action of microbial chemotaxis ( Bücking et al, 2008 ; Cao et al, 2022 ). It is suggested that the different regulations of the abundance of Bacillus , Flavobacterium , and Pseudomonas resulted from the interaction among nematodes, fungi, and plants in rhizosphere soils.…”