As a result of analyzing the internal transcribed spacer (ITS) and 5 0 end of the EF-1a sequence of 145 isolates of Metarhizium spp. isolated from soil in Japan using selective agar medium, eight species were identified. ITS sequence analysis divided the isolates into three clades. Two were identified as M. flavoviride var. pemphigi and M. lepidiotae, respectively. EF-1a sequence analysis identified the other clades as six species: M. anisopliae, M. brunneum, M. guizhouense, M. majus, M. pingshaense and M. robertisii. The distribution of M. flavoviride var. pemphigi was restricted to forest or wood soil, and conidial sizes of M. guizhouense and M. majus were incongruent with the phylogeny based on the sequence of the 5 0 end of EF-1a.
Beauveria bassiana, known for its entomopathogenic characteristics, is the most widely used biocontrol agent against many insect pests and may also be active against soil-borne pathogens. It inhabits the surfaces or inner tissues of various plant species without causing any visible signs or symptoms. Here we show that B. bassiana strain GHA, the active ingredient of a commercial microbial insecticide, colonises tomato plants. GHA grew on intact leaf surfaces of tomato in high humidity, but never entered stomata. Viable hyphae and conidia were detected, and the population on inoculated leaves significantly increased until 14 days after inoculation. On tomato leaves, GHA conidiated normally via conidiophores and phialides, and also via microcycle conidiation (conidiophores and phialides form directly from germ tubes and produce conidia). Hyphae were also detected inside the rachis, even more frequently after plant surfaces were scarified. These results suggested that B. bassiana strain GHA can grow epiphytically and endophytically on tomato plants.
Two new species of Metarhizium, M. bibionidarum and M. purpureogenum are newly described from Japan. Metarhizium bibionidarum is the phylogenetic sister species of M. pemphigi and a member of the M. flavoviride species complex. It is distinguished morphologically from M. pemphigi by its larger conidia. The species is based on a collection of an infected March fly larva (Diptera: Bibionidae) but is also known to occur on fruit beetle (Coleoptera: Scarabaeidae) encountered in France. Metarhizium purpureogenum was isolated from soil by plating and insect baiting methods and representes a unique phylogenetic lineage placed outside of the M. anisopliae and M. flavoviride species complexes. Three isolates of M. purpureogenum excreted a distinctive red-purple pigment into agar medium when co-cultured with M. robertsii or Aspergillus oryzae.
Cladosporium fulvum, the causal fungus of leaf mould of tomato, is present in most countries that grow tomatoes, and is an economic problem, particularly in Japan. The diverse, complex race structure of C. fulvum in Japan enables the fungus to overcome all resistant commercial cultivars. It was noted that C. fulvum lesions on tomato leaves in the greenhouse were overgrown with white mycelia and that leaf mould did not spread further. Two isolates from the white mycelia, designated 414‐2 and 414‐3, were identified from morphological and phylogenetic analyses as the mycoparasite Dicyma pulvinata. Scanning electron microscopy of inoculated leaves showed the mycoparasite had coiled around C. fulvum hyphae around stomata. Microscopic analysis revealed that C. fulvum, engineered to express green fluorescent protein, died when entwined by the isolates only when cocultured in the absence of a carbon source. These results indicate that these isolates are mycoparasitic fungi that absorbed nutrients from C. fulvum. Two isolates and four strains were evaluated according to their abilities to control disease caused by C. fulvum, form conidia and produce an antifungal agent. Isolate 414‐3 parasitized hyphae of C. fulvum on plants in the greenhouse and inhibited leaf mould caused by all physiological races that cause problems for tomato production in Japan. This indigenous isolate of D. pulvinata may thus serve to control the foliar pathogen C. fulvum.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.