Mayekawa MFG. Co. Ltd, Fujinomiya Shizuoka, Japan

Background and objectives
It is possible that endophytes provide their host plant with insect resistance, disease resistance,and also resistance to environmental stresses. In artificial inoculations with an endophyte, we obtained infected individual plants of rough blue-grass (Poa trivialis)showing insect resistance.

Materials and methods
Plant leaves were cut off native Poa (FERM P-15862) collected in Japan and treated with ethanol and sodium chloride solution. They were then laid on the PDA media and endophytes were isolated. The seeds of rough blue-grass were sterilized and then were laid on the agar media. The inoculation method was as follows: slits were made by cutting vertically with knife at the growing point of germinated plants, then mycelia were inserted in the slits and plants were planted in the agar media. After transfer to pot culture, the leaf sheath part of the plants were stripped off and the leaf sheaths were stained with anilin-blue and examined for mycelia using a microscope. To assay insect resistance, leaf sections from infected plants and control uninfected plants were placed in Petri dishes along with about 200 individuals of the lawn grass cutworm or the blue grass webworm.

Results and conclusions
The infected plants identified after potting were found to be few. In the assay of insect resistance, feeding damage by the pest was observed only on the control and no damage was caused in the infected plants. Even when the control plants were thoroughly damaged by feeding, the leaves of infected plants remained almost intact. In the field test of insect resistance the feeding damage by the cutworm was observed only on the control plants and no damage was caused in the infected plants.

The elucidation of the mechanism of insect resistance is in progress. We are reseaching some alkaloids, such as peramine, ergopeptine and pyrrolizidines,by using reverse-phase HPLC and capillary GC.