Aspergillus flavus NRRL 35739, a Poor Biocontrol Agent, May Have Increased Relative Expression of Stress Response Genes

Pennerman, Kayla K.; Yin, Guohua; Bennett, Joan W.; Hua, Sui-Sheng T.

doi:10.3390/jof5020053

Cited by 12 publications

(9 citation statements)

References 93 publications

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“…Isolates WRRL1519 (Yin et al ) and NRRL35739 (TX13‐5) are atoxigenic L‐type A. flavus. Although WRRL1519 and NRRL35739 have been mentioned as biocontrol strains, no field tests have been carried out with WRRL1519 and NRRL35739 is not an effective biocontrol strain (Pennerman et al ). AF36, K49 and NRRL21882 also considered L‐type A. flavus are atoxigenic biocontrol strains (Cotty ; Abbas et al ; Weaver et al ).…”

Section: Methodsmentioning

confidence: 99%

Genome‐wide nucleotide variation distinguishesAspergillus flavusfromAspergillus oryzaeand helps to reveal origins of atoxigenicA. flavusbiocontrol strains

Chang

2019

J Appl Microbiol

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Aims: To use genome-wide single nucleotide polymorphisms (total SNPs) to develop a molecular method for distinguishing Aspergillus flavus and Aspergillus oryzae. Methods and Results: Thirteen A. flavus and eleven A. oryzae genome sequences were obtained from the National Center for Biotechnology Information. These sequences were analysed by Mauve, a multiple-genome alignment program, to extract total SNPs between isolates of A. flavus, A. oryzae, or the two species. Averages of total SNPs of A. flavus isolates belonging to the same sclerotial morphotype (L-type = 178 952 AE 14 033; S-type = 133 188 AE 16 430) and A. oryzae isolates (152 336 AE 49 124) were consistently lower than those between the morphotypes and between the two species. Averages of total SNPs for L-type vs S-type (300 116 AE 1562) and S-type A. flavus vs A. oryzae (301 797 AE 4123) were similar but were 36% greater than that of L-type A. flavus vs A. oryzae (226 240 AE 10 779). Based on the devised criterion, ATCC 12892, Aspergillus oryzae (Ahlburg) Cohn, which had an averaged total SNPs 10-fold greater than that of other A. oryzae isolates, was determined to be close to Aspergillus parasiticus. Atoxigenic A. flavus field isolates, WRRL1519 and NRRL35739, were shown to more closely resemble A. oryzae than toxigenic L-type A. flavus. Biocontrol strains AF36 and K49 were genetically close to toxigenic L-type A. flavus. NRRL21882, the active agent of the commercialized biocontrol product Afla-Guard â GR, was genetically distant from all other A. flavus isolates. Conclusions: The close genetic relatedness between A. flavus and A. oryzae was confirmed and the evolutionary origins of atoxigenic A. flavus biocontrol strains were revealed. Significance and Impact of the Study: The study provides a greater understanding of genome similarity and dissimilarity between A. flavus and A. oryzae. The method can be an auxiliary technique for identifying A. flavus, A. oryzae.

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Section: Methodsmentioning

confidence: 99%

Genome‐wide nucleotide variation distinguishesAspergillus flavusfromAspergillus oryzaeand helps to reveal origins of atoxigenicA. flavusbiocontrol strains

Chang

2019

J Appl Microbiol

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“…YLR162W is particularly interesting, as this gene is believed to play an important role in the response to antimicrobial peptides [ 81 ]. CsbD is a general stress response protein with an unknown function [ 82 , 83 ]. This gene has been identified among highly expressed genes in fungi such as A. flavus NRRL 35739 [ 82 ].…”

Section: Resultsmentioning

confidence: 99%

“…CsbD is a general stress response protein with an unknown function [ 82 , 83 ]. This gene has been identified among highly expressed genes in fungi such as A. flavus NRRL 35739 [ 82 ]. None of these genes have been characterized in Epichloë yet, however, the high expression levels of these genes in at least two endophyte strains representing different taxa suggest important roles during symbiosis and warrant further investigation.…”

Section: Resultsmentioning

confidence: 99%

Global Changes in Asexual Epichloë Transcriptomes during the Early Stages, from Seed to Seedling, of Symbiotum Establishment

et al. 2021

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Asexual Epichloë fungi are strictly seed-transmitted endophytic symbionts of cool-season grasses and spend their entire life cycle within the host plant. Endophyte infection can confer protective benefits to its host through the production of bioprotective compounds. Inversely, plants provide nourishment and shelter to the resident endophyte in return. Current understanding of the changes in global gene expression of asexual Epichloë endophytes during the early stages of host-endophyte symbiotum is limited. A time-course study using a deep RNA-sequencing approach was performed at six stages of germination, using seeds infected with one of three endophyte strains belonging to different representative taxa. Analysis of the most abundantly expressed endophyte genes identified that most were predicted to have a role in stress and defence responses. The number of differentially expressed genes observed at early time points was greater than those detected at later time points, suggesting an active transcriptional reprogramming of endophytes at the onset of seed germination. Gene ontology enrichment analysis revealed dynamic changes in global gene expression consistent with the developmental processes of symbiotic relationships. Expression of pathway genes for biosynthesis of key secondary metabolites was studied comprehensively and fuzzy clustering identified some unique expression patterns. Furthermore, comparisons of the transcriptomes from three endophyte strains in planta identified genes unique to each strain, including genes predicted to be associated with secondary metabolism. Findings from this study highlight the importance of better understanding the unique properties of individual endophyte strains and will serve as an excellent resource for future studies of host-endophyte interactions.

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“…The datasets comprised RNA-Seq reads from A. fumigatus incubated alone or with human dendritic cells (PRJEB1583; read accessions ERR236917, ERR236920, ERR236932, ERR236939, ERR236940, ERR236942, ERR236948, ERR236949, ERR236951, ERR236953, ERR236959, ERR236962, ERR236963, ERR236972), or with macrophage-like cells (PRJNA560197; read accessions SRR9965307, SRR9965308, SRR9965309). The sequencing reads were processed as previously described with slight modifications [23]. Briefly, read quality was checked, then aligned to the A. fumigatus Af293 genome (NCBI GenBank assembly GCA_000002655.1) guided by the respective GFF3 file [82].…”

Section: Identification Of a Flavus And A Fumigatus Proteins With Ementioning

confidence: 99%

“…Phytopathogenicity genes necessary for disease development include those that are involved in host recognition, signaling, secondary metabolite synthesis, cell wall integrity, appressorial formation, degradation of host cuticle and cell wall, uptake of nutrients and genes with unknown roles [20]. For both plant and animal pathogens, the ability to withstand abiotic stresses within the host environment, such as hypoxia, oxidative burst and mammalian body temperatures, are likely additional virulence factors [16,19,[21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Identifying candidate Aspergillus pathogenicity factors by annotation frequency

et al. 2020

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Background Members of the genus Aspergillus display a variety of lifestyles, ranging from saprobic to pathogenic on plants and/or animals. Increased genome sequencing of economically important members of the genus permits effective use of “-omics” comparisons between closely related species and strains to identify candidate genes that may contribute to phenotypes of interest, especially relating to pathogenicity. Protein-coding genes were predicted from 216 genomes of 12 Aspergillus species, and the frequencies of various structural aspects (exon count and length, intron count and length, GC content, and codon usage) and functional annotations (InterPro, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes terms) were compared. Results Using principal component analyses, the three sets of functional annotations for each strain were clustered by species. The species clusters appeared to separate by pathogenicity on plants along the first dimensions, which accounted for over 20% of the variance. More annotations for genes encoding pectinases and secondary metabolite biosynthetic enzymes were assigned to phytopathogenic strains from species such as Aspergillus flavus. In contrast, Aspergillus fumigatus strains, which are pathogenic to animals but not plants, were assigned relatively more terms related to phosphate transferases, and carbohydrate and amino-sugar metabolism. Analyses of publicly available RNA-Seq data indicated that one A. fumigatus protein among 17 amino-sugar processing candidates, a hexokinase, was up-regulated during co-culturing with human immune system cells. Conclusion Genes encoding hexokinases and other proteins of interest may be subject to future manipulations to further refine understanding of Aspergillus pathogenicity factors.

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Aspergillus flavus NRRL 35739, a Poor Biocontrol Agent, May Have Increased Relative Expression of Stress Response Genes

Cited by 12 publications

References 93 publications

Genome‐wide nucleotide variation distinguishesAspergillus flavusfromAspergillus oryzaeand helps to reveal origins of atoxigenicA. flavusbiocontrol strains

Genome‐wide nucleotide variation distinguishesAspergillus flavusfromAspergillus oryzaeand helps to reveal origins of atoxigenicA. flavusbiocontrol strains

Global Changes in Asexual Epichloë Transcriptomes during the Early Stages, from Seed to Seedling, of Symbiotum Establishment

Identifying candidate Aspergillus pathogenicity factors by annotation frequency

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