Neotyphodium Research and Application in New Zealand

Entomologia Exp Applicata

2008

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 μ g/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.

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fungal loline alkaloids in grass–endophyte associations confer resistance to the rice leaf bug, Trigonotylus caelestialium

Shiba¹,

Entomologia Exp Applicata

2008

“…The endophyte-infected L. perenne used in this experiment may not be suitable for pasture use since it may contain mammalian toxins; however, it is possible to artificially isolate and re-inoculate the fungi to make novel associations of plants and fungi (Latch and Christensen, 1985), and cultivars of forage grasses artificially inoculated with livestock-friendly strains of Neotyphodium species are now commercially available in Australia, New Zealand, and the USA (Bouton and Easton, 2005;Easton and Tapper, 2005;Wheatley, 2005). If we can select endophyte strains, or infected grasses with insect-repelling effects but not with mammal toxicity, it will assist the breeding of forage grasses free from insect pest problems, such as attacks from O. furnacalis and S. inferens.…”

Section: Discussionmentioning

confidence: 99%

Inhibitory effect of an endophytic fungus, Neotyphodium lolii, on the feeding and survival of Ostrinia furnacalis (Guenee) (Lepidoptera: Pyralidae) and Sesamia inferens (Walker) (Lepidoptera: Noctuidae) on infected Lolium perenne

Shiba

2010

Appl. Entomol. Zool.

To examine the feasibility of using endophytic fungi (/endophyte) as biological control agents against insect pests of host plants, the effect of Neotyphodium lolii, an endophyte living in perennial ryegrass, Lolium perenne L., was studied using two species of caterpillars: the Oriental corn borer, Ostrinia furnacalis (Guenee) (Lepidoptera: Pyralidae) and the pink borer, Sesamia inferens (Walker) (Lepidoptera: Noctuidae). Choice and no-choice feeding tests using endophyte-infected and endophyte-free clonal L. perenne indicate that endophyte-infected L. perenne have excellent resistance to O. furnacalis and S. inferens. Larvae of O. furnacalis significantly preferred endophyte-free to endophyte-infected grass. The ratio of surviving insects rapidly declined on infected grass and the survival curve on infected grass was similar to that of larvae of the no-food control. A similar trend occurred with S. inferens. These results indicate that N. lolii-infected L. perenne contains strong deterrent or toxic effects that affect O. furnacalis and S. inferens feeding and survival.

“…Lolitrem B (indole diterpene) is tremorogenic and causes staggers in mammals (Gallagher et al, 1981). Some Neotyphodium-grass combinations that contain little or no mammalian toxin, but still contain invertebrate toxins, are used in forage grasses (Bouton & Easton, 2005;Easton & Tapper, 2005;Wheatley, 2005). Loline alkaloids *Correspondence and present address: Takuya Shiba, National Agricultural Research Center, National Agriculture and Food Research Organization 3-1-1 Kannondai, Tsukuba, Ibaraki 305-8666, Japan.…”

Section: Introductionmentioning

confidence: 99%

“…E-mail: takuyas@affrc.go.jp (pyrrolizidines), mainly observed as N-formylloline and N-acetylloline in Neotyphodium-grass associations, are broadly insecticidal (Bush et al, 1997), but seem to have negligible effects on vertebrates (Schardl et al, 2007). Some Neotyphodium-grass combinations that contain little or no mammalian toxin, but still contain invertebrate toxins, are used in forage grasses (Bouton & Easton, 2005;Easton & Tapper, 2005;Wheatley, 2005).…”

Section: Introductionmentioning

confidence: 99%

Evaluating the fungal endophyte Neotyphodium occultans for resistance to the rice leaf bug, Trigonotylus caelestialium, in Italian ryegrass, Lolium multiflorum

Shiba

Entomologia Experimentalis Et Applicata

Arakawa

2011

Fungal endophytes of the genus Neotyphodium (Ascomycota: Clavicipitaceae) form symbiotic associations with many grass species of the subfamily Pooideae, including some important forage and turf grasses from the genus Lolium. Some Neotyphodium-infected grasses have enhanced resistance to the rice leaf bug, Trigonotylus caelestialium (Kirkaldy) (Heteroptera: Miridae), one of the major pests in rice production in Japan. The insects can grow on Lolium grasses and thus cause a conflict of interest between production of forage and rice. Endophyte-mediated resistance to T. caelestialium is likely to be conferred by N-formylloline, one of the major loline alkaloids (saturated 1-aminopyrrolizidines) observed in some grass-Neotyphodium associations. We checked the feasibility of using Neotyphodium occultans, the native endophyte of Italian ryegrass (Lolium multiflorum Lam.), to reduce T. caelestialium, as this endophyte produces N-formylloline, but no known mammalian toxins. To this end, we conducted choice and no-choice feeding assays using T. caelestialium first instars and 35 N. occultans-infected Italian ryegrass plants with different in planta N-formylloline concentration. Some N. occultans-infected ryegrass showed significant resistance to T. caelestialium. The preference and the survival of this insect were considerably lower on infected plants, and the higher the in planta N-formylloline concentration, the greater the adverse effects on the insect. The incremental risk of death of the insect was assumed to be due to intake of the chemical, and in addition, to the decreased amount of feeding caused by its insect-deterrent effect. These results indicated that the use of the N. occultans-grass associations has potential to reduce T. caelestialium propagation in ryegrass crops. The breeding of N. occultans-infected Italian ryegrass cultivars with high N-formylloline concentrations should be an effective way to develop pasture grasses with a greater protective effect against T. caelestialium.