Plant-microbe rhizosphere interactions mediated by Rehmannia glutinosa root exudates under consecutive monoculture

Abstract

Under consecutive monoculture, the biomass and quality of Rehmannia glutinosa declines significantly. Consecutive monoculture of R. glutinosa in a four-year field trial led to significant growth inhibition. Most phenolic acids in root exudates had cumulative effects over time under sterile conditions, but these effects were not observed in the rhizosphere under monoculture conditions. It suggested soil microbes might be involved in the degradation and conversion of phenolic acids from the monocultured plants. T-RFLP and qPCR analysis demonstrated differences in both soil bacterial and fungal communities during monoculture. Prolonged monoculture significantly increased levels of Fusarium oxysporum, but decreased levels of Pseudomonas spp. Abundance of beneficial Pseudomonas spp. with antagonistic activity against F. oxysporum was lower in extended monoculture soils. Phenolic acid mixture at a ratio similar to that found in the rhizosphere could promote mycelial growth, sporulation, and toxin (3-Acetyldeoxynivalenol, 15-O-Acetyl-4-deoxynivalenol) production of pathogenic F. oxysporum while inhibiting growth of the beneficial Pseudomonas sp. W12. This study demonstrates that extended monoculture can alter the microbial community of the rhizosphere, leading to relatively fewer beneficial microorganisms and relatively more pathogenic and toxin-producing microorganisms, which is mediated by the root exudates.

Assaying the potential autotoxins and microbial community associated with Rehmannia glutinosa replant problems based on its ‘autotoxic circle’

“…W 12 (Wu et al 2015). Research has confirmed that F. oxysporum is the pathogenic pathogens of R. glutinosa disease (Li et al 2013) and that most strains of Pseudomonas showed antagonistic activity against F. oxysporum (Borah et al 2015;Chin-A-Woeng et al 2000;Srinivasan et al 2009).…”

Insights into the Regulation of Rhizosphere Bacterial Communities by Application of Bio-organic Fertilizer in Pseudostellaria heterophylla Monoculture Regime

“…The monocultured plots without microbial fertilizer treatment (NMF) were found to have the lowest pH ( Figure 3 ). Previous studies have shown that consecutive monoculture of many plants could lead to a significant decrease in soil pH (Meriles et al, 2009; Wu et al, 2015). Many pathogenic fungi including Fusarium spp.…”

Identification of Rehmannia glutinosa L. NB-ARC family proteins and their typical changes under consecutive monoculture stress

“…The addition of phenolic acids caused significant increases in the population of pathogenic microorganisms in plate cultures and field experiments Zhang et al 2016). Allelochemicals of root exudates mediated adverse chemotaxis of rhizospheric microbes (Wu et al 2015;Zhang et al 2013). The immune systems of R. glutinosa are activated and finally compromised due to continuous attack by a large number of proliferating pathogens.…”

“…Given these typical characteristics, R. glutinosa is an ideal material for studying the mechanism of formation of consecutive monoculture problems Wen et al 2002). Previous studies have indicated that some biotic and abiotic stress factors involved in the formation of consecutive monoculture problems in R. glutinosa (Tian et al 2017;Wu et al 2015). In consecutive monocultures of R. glutinosa, root exudates selectively attract pathogenic microbes, which colonize the root surface in consecutive monocultures of R. glutinosa.…”

“…In consecutive monocultures of R. glutinosa, root exudates selectively attract pathogenic microbes, which colonize the root surface in consecutive monocultures of R. glutinosa. This effect ultimately causes the proliferation of harmful microorganisms in the rhizosphere and induces adverse chemotaxis from "bacterial" to "fungal" types (Wu et al , 2015Zhang et al 2011;Zhang and Lin 2009). A specific pathogenic Fusarium oxysporum screened from rhizosphere soil microorganisms has been identified as Fusarium oxysporum f.sp.…”