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Epichloë fungi were isolated from Brachypodium sylvaticum with or without symptoms of choke disease collected at five sites in Japan. The morphological characteristics of the fungi corresponded to the description of Epichloë sylvatica . A phylogenetic analysis revealed that isolates derived from surface-sterilized tillers and single ascospores from stroma on its hosts were included in the same clade with those identified as E. sylvatica . In Japan, to date, Epichloë fungi causing choke disease on B. sylvaticum were listed only as Epichloë typhina . We confirmed that both stroma-forming and symptomless endophytes inhabiting B. sylvaticum in Japan are E. sylvatica , not E. typhina . [ABSTRACT FROM AUTHOR] more...

A toothpick inoculation method was applied for evaluating the disease severity and infection frequency of Pythium root rot, which seriously restricts forage corn production in Japan. Seven corn hybrids were inoculated with toothpicks infested with Pythium arrhenomanes, the causal pathogen of the disease. Between 2011 and 2013, toothpicks were inserted into holes of the bottom stalks of corn plants just above the ground at the silking stage. At the inoculation plots throughout the experimental years, the infection frequencies of highly susceptible hybrids were stable even under suboptimal climate conditions. Therefore, we have concluded that the toothpick method is useful especially for discarding highly susceptible hybrids based on the data obtained from a single year. Further experiments will be required to overcome such problems as the low correlation between hybrids and their parental inbreds, and the development of more accurate screening systems for selecting resistant genotypes. [ABSTRACT FROM AUTHOR] more...

Epichloë ( Neotyphodium) endophytes are symbiotic fungi in association with gramineous plants and produce a range of alkaloids that enhance the resistance of host plants to insect pests. N-formylloline, one of the Epichloë-produced alkaloids, is known to be toxic to some insects but not to mammals. Therefore, Epichloë-infected grasses with high N-formylloline concentrations are expected to reduce the population of some insect pests in meadows. To assess the adverse effects of N-formylloline on the survival of the sorghum plant bug ( Stenotus rubrovittatus) known as a major pest, artificial feeding of N-formylloline through feeding sachets was carried out. N-formylloline reduced the survival of S. rubrovittatus, even at 50 ppm, which was considerably lower than the concentrations in most Epichloë-infected grasses. The results suggest that N-formylloline in Epichloë-infected grasses can reduce the population of S. rubrovittatus in meadows. [ABSTRACT FROM AUTHOR] more...

Plant symbiotic fungi (endophytes) of the genus Neotyphodium [anamorphs, asexual derivatives of Epichloë (Ascomycota: Clavicipitaceae)] often associate with grass species of the subfamily Pooideae, which includes important forage and turf species. These endophytes are known to produce a range of alkaloids that enhance their host's resistance to insects or are toxic to grazing animals. Among the alkaloids, loline alkaloids (saturated 1-aminopyrrolizidines) are generally observed in the highest concentrations in many Neotyphodium–grass symbiotic associations, and are known to be toxic to insects but not to mammals. Some Neotyphodium-infected grasses have enhanced resistance to rice leaf bug, Trigonotylus caelestialium (Kirkaldy) (Heteroptera: Miridae), one of the major pests for rice production in Japan. Our laboratory experiments quantified the effects of purified loline ( N-formylloline) and in planta synthesis of loline alkaloids by meadow fescue [ Lolium pratense (Huds.) S.J. Darbyshire (syn. Festuca pratensis Huds.)]– Neotyphodium uncinatum (Gams, Petrini & Schmidt) Glenn, Bacon & Hanlin and Italian ryegrass ( Lolium multiflorum Lam.)– Neotyphodium occultans Moon, Scott & Christensen associations on the development and survival of T. caelestialium. No-choice feeding assays with laboratory populations of the insect revealed that their growth was significantly decreased by the infected grasses, and the effect was greater for N. uncinatum than for N. occultans, in keeping with differences in N-formylloline concentrations in the plants. Artificial feeding of N-formylloline through feeding sachets indicated that the chemical has an adverse effect on survival of larvae, even at the lowest concentration tested (50 µg/g), which was considerably lower than the typical concentrations in many Neotyphodium–grass association s. The results confirmed the ability of Neotyphodium-infected forage grasses to control T. caelestialium propagation in meadows, which may cause damages to nearby rice paddies. [ABSTRACT FROM AUTHOR] more...

Neotyphodiumfungal endophytes form mutualistic symbiotic associations with many grasses of the subfamily Pooideae, including important forage and turfgrass species. This relationship provides a competitive advantage to the host plant by increasing abiotic/biotic stress tolerance, such as its resistance to drought, diseases, and insect pests. The insect deterrent effects of endophytes are now receiving attention in Japan, as insect pests growing in meadows are causing problems in adjacent rice paddies. One of the most serious problems is the kernel spotting of rice grains caused by the rice leaf bug,Trigonotylus caelestialiumKirkaldy (Heteroptera: Miridae), which reproduces onLoliumspecies grown as forage. To determine the potential ofNeotyphodiumendophytes to reduce the invasion of rice crops byT. caelestialiumfrom adjacentLoliumcrops, we carried out choice and no-choice feeding tests using endophyte-infected and endophyte-free clonal perennial ryegrass (Lolium perenneL.) (Poaceae). Our experiments revealed that the presence of theNeotyphodiumendophyte strongly deterred the feeding of both first-instar larvae and adults ofT. caelestialium. These results show the potential ofNeotyphodiumendophytes to reduce the number ofT. caelestialiumin forage fields and grasslands, and thus to reduce the damage to rice grains caused by this insect pest. [ABSTRACT FROM AUTHOR] more...