Journal of Microbiology

Research Support, Non-U.S. Gov'ts

Cloning, Annotation and Expression Analysis of Mycoparasitism-Related Genes in Trichoderma harzianum 88: Lin Yao , Qian Yang , Jinzhu Song , Chong Tan , Changhong Guo , Li Wang , Lianhai Qu , Yun Wang; J. Microbiol. 2013;51(2):174-182. Published online April 27, 2013; DOI: https://doi.org/10.1007/s12275-013-2545-7

Abstract: Trichoderma harzianum 88, a filamentous soil fungus, is an effective biocontrol agent against several plant pathogens. High-throughput sequencing was used here to study the mycoparasitism mechanisms of T. harzianum 88. Plate confrontation tests of T. harzianum 88 against plant pathogens were conducted, and a cDNA library was constructed from T. harzianum 88 mycelia in the presence of plant pathogen cell walls. Randomly selected transcripts from the cDNA library were compared with eukaryotic plant and fungal genomes. Of the 1,386 transcripts sequenced, the most abundant Gene Ontology (GO) classification group was “physiological process”. Differential expression of 19 genes was confirmed by real-time RT-PCR at different mycoparasitism stages against plant pathogens. Gene expression analysis revealed the transcription of various genes involved in mycoparasitism of T. harzianum 88. Our study provides helpful insights into the mechanisms of T. harzianum 88-plant pathogen interactions.

NOTE] Mitochondrial Phylogeny Reveals Intraspecific Variation in Peronospora effusa, the Spinach Downy Mildew Pathogen: Young-Joon Choi , Marco Thines , Jae-Gu Han , Hyeon-Dong Shin; J. Microbiol. 2011;49(6):1039-1043. Published online December 28, 2011; DOI: https://doi.org/10.1007/s12275-011-1069-2

Abstract: Since about two hundred years, downy mildew caused by Peronospora effusa is probably the most economically important disease of spinach (Spinacia oleracea). However, there is no information on the global phylogeographic structure of the pathogen and thus it is unclear whether a single genotype occurs worldwide
or whether some local genetic variation exists. To investigate the genetic variability of this pathogen, a sequence analysis of two partial mitochondrial DNA genes, cox2 and nad1, was carried out. Thirty-three specimens of Peronospora effusa from four continents were analyzed, including samples from Australia, China, Japan, Korea, Mexico, Russia, Sweden, and the USA. Despite the potential anthropogenic admixture of genotypes, a phylogeographic pattern was observed, which corresponds to two major groups, an Asian/Oceanian clade and another group, which includes American/European specimens. Notably, two of six Japanese specimens investigated did not belong to the Asian/Oceanian clade, but were identical to three of the specimens from the USA, suggestive of a recent introduction from the USA to Japan. As similar introduction events may be occurring as a result of the globalised trade with plant and seed material, a better knowledge of the phylogeographic distribution of pathogens is highly warranted for food security purposes.

Diversity of Actinomycetes Antagonistic to Plant pathogenic Fungi in Cave and Sea-Mud Soils of Korea: Kim, Beom Seok , Lee, Jung Yeop , Hwang, Byung Kook; J. Microbiol. 1998;36(2):86-92.

Abstract: To isolate actinomycetes antagonistic to plant pathogenic fungi, soil samples were collected from caves and sea-shores in Korea. The 481 actinomycetes were isolated from the soil samples examined, representing more than 50% of total counts. Nocardioform actinomycetes were rare actinomycete genera. Saccharomonospora could be isolated only in 3 cave soil samples from Cheondong, Kosoo, and Nodong, but was not present in all the sea-mud soils examined. Dactylosporangium, Saccharomonospora, and Streptosporangium were very rare in both cave and sea-mud soils. The 311 of 481 actinomycete isolates inhibited the mycelial growth of at least one of the tested fungi. The isolation rates of antagonistic actinomycetes from cave soils ranged from 45.7% to 78%, and those of sea-mud soils were from 59.1% to 66.0%. The 96 of 136 Streptomyces isolates from cave soils, and 93 of 133 isolates from sea-mud soils showed antifungal activity. The proportion of antagonistic isolates of Nocardioform actinomycetes (13.6%) was lower than that of other genera. Among the actinomycetes from sea-mud soils, Dactylosporangium and Streptosporangium had highest proportions of actinomycete antagonists of 85.7% and 80%, respectively. The isolation rate of Nocardioform antagonist from sea-mud soils was 11.1% similar in the cabve soils. Streptomyces strains showed higher antifungal activities against plant pathogenic fungi than did other rare actinomycete antagonists.

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