Enhancement of trichothecene mycotoxins of Fusarium oxysporum by ferulic acid aggravates oxidative damage in Rehmannia glutinosa Libosch

Abstract

Rehmannia glutinosa is an important medicinal herb that cannot be replanted in the same field due to the effects of autotoxic substances. The effects of these substances on R. glutinosa in continuous cropping systems are unknown. In the present study, bioassays revealed that R. glutinosa exhibited severe growth restriction and higher disease indices in the FO+FA (F.oxysporum pretreated with ferulic acid) treatment. The increases in the contents of MDA and H2O2 were greater in the FA+FO treatment than in the FA or FO only treatments, respectively. Consistent with this result, the enzyme activities in the seedlings increased with treatment time. To identify the main factor underlying the increased pathogenicity of FO, macroconidia and trichothecene mycotoxins coproduced by FO were separated and used to treat R. glutinosa seedlings. The MDA and H2O2 contents were similar in the seedlings treated with deoxynivalenol and in the FA+FO treatment. Quantification of the relative expression of certain genes involved in Ca2+ signal transduction pathways suggested that trichothecene mycotoxins play an important role in the increased pathogenicity of FO. In conclusion, FA not only directly enhances oxidative damage in R. glutinosa but also increases wilting symptom outbreaks by promoting the secretion of trichothecene mycotoxins by FO.

Comparative Metagenomic Analysis of Rhizosphere Microbial Community Composition and Functional Potentials under Rehmannia glutinosa Consecutive Monoculture

“…Various studies indicated that consecutive monoculture of medicinal plants led to the accumulation of toxic compounds in soil, such as microbial secondary metabolites, autotoxins released by plant roots, and so on [43,44,45]. In this study, it was found that the percentage of reads categorized to penicillin and cephalosporin biosynthesis (ko00311) was significantly higher in CM than in NP (Figure S9).…”

“…Furthermore, the metagenomics analysis showed that the levels of the clusters of defense mechanisms (i.e., antibiotic resistance, ABC transporters, efflux transporter) and DNA repair were higher in CM than in NP for harmful/indicator microorganisms ( Figures S12 and S14 ), which might confer them high tolerance levels to toxic or antimicrobial compounds [ 41 , 42 ]. Various studies indicated that consecutive monoculture of medicinal plants led to the accumulation of toxic compounds in soil, such as microbial secondary metabolites, autotoxins released by plant roots, and so on [ 43 , 44 , 45 ]. In this study, it was found that the percentage of reads categorized to penicillin and cephalosporin biosynthesis (ko00311) was significantly higher in CM than in NP ( Figure S9 ).…”

Rehmannia glutinosa Replant Issues: Root Exudate-Rhizobiome Interactions Clearly Influence Replant Success

“…while inhibiting growth of the beneficial Pseudomonas strain ( Wu et al, 2015 ). Bioassay showed that high concentration of phenolic acids were not only phytotoxic to R. glutinosa seedlings but also enhanced the oxidative damage and outbreak of wilting symptom in R. glutinosa together with F. oxysporum ( Li et al, 2012 , 2016 ). These findings suggested that extended monoculture of R. glutinosa altered the soil microbial community through the presence of phenolic acids in root exudates, resulting in the decline of beneficial bacteria with antagonistic activity against pathogens and the explosive growth and proliferation of F. oxysporum .…”

“…These findings suggested that extended monoculture of R. glutinosa altered the soil microbial community through the presence of phenolic acids in root exudates, resulting in the decline of beneficial bacteria with antagonistic activity against pathogens and the explosive growth and proliferation of F. oxysporum . Potentially, the phytotoxicity of accumulated phenolic acids together with the pathogenicity of proliferating associated phytopathogens were reported as potentially responsible for the replant problems/diseases of R. glutinosa ( Wu et al, 2015 , 2018a ; Li et al, 2016 ).…”

“Quantity-effect” research strategy for comparison of antioxidant activity and quality of Rehmanniae Radix and Rehmannia Radix Praeparata by on-line HPLC-UV-ABTS assay

“…Shu Dihuang is usually applied to in the traditional Chinese medicine formulas that can nourish the Yin deficiency of liver, kidney and heart [1][2][3]. Many clinical and experimental studies have reported that the root of R. glutinosa possesses hypoglycaemic [4], anti-oxidant [5,6] anti-cancer [7], anti-inflammatory [8], and immuneenhancement effects [9].…”