possible symbiosis and evaluation of endomycorrhizal fungus piriformospora indica effects in rice plant

the mycorrhizal fungi are the most important micro-organism among the soil micro flora which via genetical, physiological and ecological changes lead to more yield in symbiotic plants.  the piriformospora indica sav. verma, aj. varma, rexer, g. kost & p. franken 1998, is one of well known endomycorrhizal fungus with different beneficial effects on diverse monocots (poaceae) and dicots (brassicaceae and chenopodiaceae) plants. p. indica  belongsto sebacinales, hymenomycete and basidiomycota phylum. it has been reported that p. indica is capable to symbioses with different plants. several studies showed that p. indica increases root and stem length in plants via induction of growth promotion hormones, more absorption of nutrients such as phosphorus and increase tolerance to salinity and drought stresses. as well p. indica causes induction of systemic acquired resistance against different diseases on roots and shoots. in this study p. indica (kind gift from prof. kogel, head of institute of phytopathology and applied zoology, university of giessen, germany) culture was grown on complex medium (cm) at 27 oc for one month. disinfected rice (local cv.tarom) seeds with 1% active chlorine were germinated on water soaked filter paper in petri plates. four days old seedling immersed in 106 ml–1 of  p. indica chlamydospores suspension for 12 hours and shacked with 40 rpm. infected and mock seedlings transferred in plates containing aqueous uchida medium for planting in soil. to detect of p. indica roots samples were stained with ink following by vierheilig et al. method with minor changes. molecular detection of p. indica  in plants carried out using tef specific primer  pairs (accession no. aj249911). result of this study showed that treated plants with p. indica,contain round to pear shaped chlamydospore formed in infected roots. the rate of tillering increased up to 50% in p. indica infected plants. as well as, the number of fertilized spikes and root length increased noticeably in p. indica   treated rice plants. studying of induced diseases resistance in p. indica treated rice plants is under progress. this is the first report of symbiosis in iranian local rice cultivar and p. indica.