an identification of arbuscular mycorrhizal fungus in kinnow mandarin (citrus nobilis x citrus deliciosa) grafted on rough lemon rootstock by polymerase chain reaction technique

an experiment was conducted, using two year old kinnow plants, budded on rough lemon rootstock, inoculated with different isolates of amf fungi viz., glomus manihotis, gigaspora gigantean and glomus mosseae singly as well as in mixed culture. five primers vans1, ns61,ns21,vaglo,vagiga specific to glomus and gigaspora species were designed and used in a polymerase chain reaction with dna extracted from mycorrhizal roots varying in colonization. glomus family-specific vaglo primer in conjunction with glomerales-specific vans1 primer, successfully amplified 190bp fragment from samples of g. manihotis and g. mosseae. this 190bp product was not detected with g. gigantean and in the un-inoculated, non colonized control plants. use of primer pair vans1-ns61 for amplification of around 1kb fragment belonging to nearly complete gene coding for the small subunit rrna was successful. further use of this 1kb product as template dna after one more round of pcr (for more amplification) in conjunction with primer pair vans1-vaglo and vans1-vagiga produced an amplicon with an expected size only for the first primer pair and not for the second primer pair. this study clearly indicates the possibility of using this technique as a tool for rapid and precise detection and identification of arbuscular mycorrhizal fungi in kinnow roots.