Root colonization and effect of biocontrol fungus Paecilomyces lilacinus on composition of ammonia-oxidizing bacteria, ammonia-oxidizing archaea and fungal populations of tomato rhizosphere

Abstract

This study investigated the effects of root-knot nematode biocontrol agent Paecilomyces lilacinus (P. lilacinus) strain PL1210 on ammonia-oxidizing microorganisms and fungal community composition of tomato rhizosphere. The exchangeable NH 4 + -N and NO 3 − -N contents were lower in inoculated soils than in the control during 60 days of incubation. Real-time quantitative polymerase chain reaction (qPCR) detected stable colonization of P. lilacinus in the tomato rhizosphere and significant inhibition of ammoniaoxidizing bacteria (AOB) and archaea (AOA), which could be responsible for the decrease of NO 3 − -N content in soil. PCR-denaturing gradient gel electrophoresis (DGGE) analysis demonstrated no significant difference in soil fungal community composition associated with the application of P. lilacinus as shown by Shannon-Wiener diversity index (H ′) and Margalef index (D). Cluster analysis showed that the composition of rhizosphere fungal community was more significantly influenced by time-related differences than by the inoculation of biocontrol agents.

Phomopsis liquidambari colonization promotes continuous cropping peanut growth by improving the rhizosphere microenvironment, nutrient uptake and disease incidence

“…The use of beneficial microorganisms to alleviate continuous cropping obstacles of peanuts is a promising method and has an irreplaceable advantage over other conventional methods . Efficient colonization is a prerequisite for the ability of exogenous microbial agents to exert their potential ecological functions .…”

“…The use of beneficial microorganisms to alleviate continuous cropping obstacles of peanuts is a promising method and has an irreplaceable advantage over other conventional methods. 4,24,29,39,40 Efficient colonization is a prerequisite for the ability of exogenous microbial agents to exert their potential ecological functions. 40 In this study, the abundance of P. liquidambari in the rhizosphere was significantly dependent on the sampling period, probably because its colonization was related to the dynamics of the root exudates and environmental factors.…”

“…4,24,29,39,40 Efficient colonization is a prerequisite for the ability of exogenous microbial agents to exert their potential ecological functions. 40 In this study, the abundance of P. liquidambari in the rhizosphere was significantly dependent on the sampling period, probably because its colonization was related to the dynamics of the root exudates and environmental factors. The decrease in P. liquidambari at the seedling stage was probably due to the competition for nutrients and ecological niches with indigenous microbes during the initial inoculation period.…”

“…The decrease in P. liquidambari at the seedling stage was probably due to the competition for nutrients and ecological niches with indigenous microbes during the initial inoculation period. Plant growth and seasonal conditions, such as increased root exudates, root surface, temperature, and relative humidity and soil moisture, were responsible for the survival and activity of the inoculated fungi, followed by an increase in abundance at the flowering stage. The decrease or disappearance of the fungus later in the season may be due to deterioration of the peanut rhizosphere environment.…”

The type three secretion system facilitates migration of Burkholderia terrae BS001 in the mycosphere of two soil-borne fungi

“…Additionally, in plant-associated soil environments, fungal hyphae can transport bacteria, such as plant-growth-promoting or biocontrol organisms, to reach distant rhizosphere or rhizoplane sites, thus promoting effects of these (Shao et al 2015). Then, the composition of the soil microbiome can be directed (Yu et al 2015), rhizosphere niches, in which root-microbiome associations were disrupted, filled (Qiu et al 2014), and phytopathogens antagonized (Tan et al 2016). Thus, bacterial dispersal along with fungal hyphae in soil is very important for a number of key soil functions.…”