Microenvironmental Interplay Predominated by Beneficial Aspergillus Abates Fungal Pathogen Incidence in Paddy Environment

Abstract

Rice fungal pathogens, responsible for severe rice yield loss and biotoxin contamination, cause increasing concerns on environmental safety and public health. In the paddy environment, we observed that the asymptomatic rice phyllosphere microenvironment was dominated by an indigenous fungus, Aspergillus cvjetkovicii, which positively correlated with alleviated incidence of Magnaporthe oryzae, one of the most aggressive plant pathogens. Through the comparative metabolic profiling for the rice phyllosphere microenvironment, two metabolites were assigned as exclusively enriched metabolic markers in the asymptomatic phyllosphere and increased remarkably in a population-dependent manner with A. cvjetkovicii. These two metabolites evidenced to be produced by A. cvjetkovicii in either a phyllosphere microenvironment or artificial media were purified and identified as 2­(3H)-benzofuranone and azulene, respectively, by gas chromatography coupled to triple quadrupole mass spectrometry and nuclear magnetic resonance analyses. Combining with bioassay analysis in vivo and in vitro, we found that 2­(3H)-benzofuranone and azulene exerted dissimilar actions at the stage of infection-related development of M. oryzae. A. cvjetkovicii produced 2­(3H)-benzofuranone at the early stage to suppress MoPer1 gene expression, leading to inhibited mycelial growth, while azulene produced lately was involved in blocking of appressorium formation by downregulation of MgRac1. More profoundly, the microenvironmental interplay dominated by A. cvjetkovicii significantly blocked M. oryzae epidemics in the paddy environment from 54.7 to 68.5% (p < 0.05). Our study first demonstrated implication of the microenvironmental interplay dominated by indigenous and beneficial fungus to ecological balance and safety of the paddy environment.

Biocontrol Ability and Mechanism of a Broad-Spectrum Antifungal Strain Bacillus safensis sp. QN1NO-4 Against Strawberry Anthracnose Caused by Colletotrichum fragariae

“…Among them, 2(3H)-benzofuranone, 2,4-bis(1,1-dimethylethyl)-phenol, and butyl isobutyl phthalate exhibited high antifungal and antibacterial activities. 2(3H)-benzofuranone produced by the indigenous fungus remarkably inhibited the mycelial growth of M. oryzae (Fan et al, 2019). 2,4-bis(1,1-Dimethylethyl)-phenol effectively inhibited the spore germination of P. cinnamomi and Aspergillus and controlled tomato fungal diseases such as early blight and gray mold (Rangel-Sánchez et al, 2014;Gao et al, 2017).…”

Proteomics Analysis Reveals the Molecular Mechanism of MoPer1 Regulating the Development and Pathogenicity of Magnaporthe oryzae

“…As reported, after the MoPER1 gene was knocked out or its expression was inhibited, the fungi was defective in growth, pathogenicity, and cell wall integrity, which indicated that MoPer1 plays an important role in the growth, development and pathogenicity of M. oryzae (Chen et al, 2018;Fan et al, 2019). To investigate MoPer1 protein's effect mechanism in M. oryzae, we applied the TMT quantitative and qualitative analysis technique to examine the DEPs between the DMoper1 mutant and Guy11.…”

Selenium Combined with Methyl Jasmonate to Control Tomato Gray Mold by Optimizing Microbial Community Structure in Plants

“…The bacteria were isolated by the plate dilution method according to Fan et al [ 33 ] with minor modifications. Ground and homogenized tomato leaves with MSe2.0 treatment (of Experiment I ) were diluted to 10 −1 –10 −5 concentration gradient, 100 μL was coated on Beef Extract Peptone Agar Medium plate, incubated at 30 °C for 24 h, and the colonies with different morphology and color were purified then stored at 4 °C.…”