Phylogeny and pathogenicity of Fusarium solani species complex (FSSC) associated with potato tubers

Identification and screening of fungicides against Piper nigrum basal Fusarium wilt disease in Hainan, China

Fusarium wilt has occurred in the main Piper nigrum cultivation regions, which seriously affects the yield and quality of P. nigrum. To identify the pathogen of this disease, the diseased roots were collected from a demonstration base in Hainan Province. The pathogen was obtained by tissue isolation method and confirmed by pathogenicity test. Based on the morphological observation, sequence analyses of TEF1-α nuclear gene, Fusarium solani was identified as the pathogen causing P. nigrum Fusarium wilt and induced symptoms on inoculated plants, including chlorosis, necrotic spots, wilt, drying, and root rot. The experiments for the antifungal activity showed that all the 11 fungicides selected in this study showed certain inhibitory effects on the colony growth of F. solani, where 2% kasugamycin AS, 45% prochloraz EW, 25 g·L-1 fludioxonil SC and 430 g·L-1 tebuconazole SC exhibited relative higher inhibitory effects with EC50 as 0.065, 0.205, 0.395, and 0.483 mg·L-1 , respectively, and were selected to perform SEM analysis and test in seeds in vitro. The SEM analysis showed that kasugamycin, prochloraz, fludioxonil, and tebuconazole might have exerted their antifungal effect by damaging F. solani mycelia or microconidia. These preparations were applied as a seed coating of P. nigrum Reyin-1. The kasugamycin treatment was most effective in reducing the harmful impact of F. solani on the seed germination. These results presented herein provide useful guidance for the effective control of P. nigrum Fusarium wilt.

Amorphophallus muelleri activates ferulic acid and phenylpropane biosynthesis pathways to defend against Fusarium solani infection

Amorphophallus sp. is an economically important crop for rural revitalization in southwest China. However, Fusarium solani often infects Amorphophallus sp. corms during storage, damaging the corm quality and affecting leaf elongation and flowering in the subsequent crop. In this study, the mechanism of resistance to F. solani was investigated in the leaf bud and flower bud corms of Amorphophallus muelleri through transcriptome and metabolome analyses. A total of 42.52 Gb clean reads and 1,525 metabolites were detected in a total of 12 samples including 3 samples each of disease-free leaf bud corms (LC), leaf bud corms inoculated with F. solani for three days (LD), disease-free flower bud corms (FC), and flower bud corms inoculated with F. solani for three days (FD). Transcriptome, metabolome, and conjoint analyses showed that 'MAPK signal transduction', 'plant-pathogen interaction', 'plant hormone signal transduction', and other secondary metabolite biosynthesis pathways, including 'phenylpropane biosynthesis', 'arachidonic acid metabolism', 'stilbene, diarylheptane and gingerolin biosynthesis', and 'isoquinoline alkaloids biosynthesis', among others, were involved in the defense response of A. muelleri to F. solani. Ultimately, the expression of six genes of interest (AmCDPK20, AmRBOH, AmWRKY33, Am4CL, Am POD and AmCYP73A1) was validated by real-time fluorescence quantitative polymerase chain reaction, and the results indicated that these genes were involved in the response of A. muelleri to F. solani. Ferulic acid inhibited the growth of F. solani, reducing the harm caused by F. solani to A. muelleri corms to a certain extent. Overall, this study lays a strong foundation for further investigation of the interaction between A. muelleri and F. solani, and provides a list of genes for the future breeding of F. solani-resistant A. muelleri cultivars.

Potential of Burkholderia sp. IMCC1007 as a biodetoxification agent in mycotoxin biotransformation evaluated by mass spectrometry and phytotoxicity analysis

Microbial degradation is considered as an attractive method to eliminate exposure to mycotoxin that cause a serious threat in agriculture global industry and severe human health problems. Compared with other more prominent mycotoxin compounds, fusaric acid (FA) biodegradation has not been widely investigated. In this study, a fusaric acid-degrading bacterium Burkholderia sp. IMCC1007 was identified by 16 S rRNA gene sequencing and its detoxification characteristics were evaluated. This strain able to utilize FA as sole energy and carbon source with growth rate (µ) of 0.18 h^- 1. Approximately 93% from the initial substrate FA concentration was almost degraded to the residual about 4.87 mg L^- 1 after 12 h of incubation. The optimal degradation conditions for pH and temperature were recorded at 6.0 with 30 °C respectively. An efficient FA degradation of strain IMCC1007 suggested its potential significance to detoxification development. Accroding to LC-MS/Q-TOF analysis, FA was bio-transformed to 4-hydroxybenzoic acid (C₇H₆O₃) and other possible metabolites. Plant treated with detoxified FA products exhibited reduction of wilting index, mitigating against FA phytoxicity effect on plant growth and photosynthesis activity. Phytotoxicity bioassay suggested that degradation product of IMCC1007 was not a potent harmful compound towards plants as compared to the parent compound, FA. As a conslusion, our study provides a new insight into the practical application of biodetoxifcation agent in controlling mycotoxin contamination.

An image-based technique for automated root disease severity assessment using PlantCV

PREMISE

Plant disease severity assessments are used to quantify plant-pathogen interactions and identify disease-resistant lines. One common method for disease assessment involves scoring tissue manually using a semi-quantitative scale. Automating assessments would provide fast, unbiased, and quantitative measurements of root disease severity, allowing for improved consistency within and across large data sets. However, using traditional Root System Markup Language (RSML) software in the study of root responses to pathogens presents additional challenges; these include the removal of necrotic tissue during the thresholding process, which results in inaccurate image analysis.

METHODS

Using PlantCV, we developed a Python-based pipeline, herein called RootDS, with two main objectives: (1) improving disease severity phenotyping and (2) generating binary images as inputs for RSML software. We tested the pipeline in common bean inoculated with Fusarium root rot.

RESULTS

Quantitative disease scores and root area generated by this pipeline had a strong correlation with manually curated values (R ² = 0.92 and 0.90, respectively) and provided a broader capture of variation than manual disease scores. Compared to traditional manual thresholding, images generated using our pipeline did not affect RSML output.

DISCUSSION

Overall, the RootDS pipeline provides greater functionality in disease score data sets and provides an alternative method for generating image sets for use in available RSML software.

Potential of Burkholderia sp. IMCC1007 as a biodetoxification agent in mycotoxin biotransformation evaluated by mass spectrometry and phytotoxicity analysis.. [DOI: 10.21203/rs.3.rs-2149358/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Microbial degradation is considered as an attractive method to eliminate exposure to mycotoxin that cause a serious threat in agriculture global industry and severe human health problems. Compared with other more prominent mycotoxin compounds, fusaric acid (FA) biodegradation has not been widely investigated. In this study, a fusaric acid-degrading bacterium Burkholderia sp. IMCC1007 was identified by 16S rRNA gene sequencing and its detoxification characteristics were evaluated. This strain able to utilize FA as sole energy and carbon source with growth rate (µ) of 0.18 h− 1. Approximately 93% from the initial substrate FA concentration was almost degraded to the residual about 4.87 mg L− 1 after 12 h of incubation. The optimal degradation conditions for pH and temperature were recorded at 6.0 with 30°C respectively. An efficient FA degradation of strain IMCC1007 suggested its potential significance to detoxification development. Accroding to LC-MS/Q-TOF analysis, FA was bio-transformed to 4-hydroxybenzoic acid (C7H6O3) and other possible metabolites. Plant treated with detoxified FA products exhibited reduction of wilting index, mitigating against FA phytoxicity effect on plant growth and photosynthesis activity. Phytotoxicity bioassay suggested that degradation product of IMCC1007 was not a potent harmful compound towards plants as compared to the parent compound, FA. As a conslusion, our study provides a new insight into the practical application of biodetoxifcation agent in controlling mycotoxin contamination.