Indian Journal of Virology

Sterility mosaic disease (SMD) is the most economically important disease of pigeonpea (Cajanus cajan) in the Indian subcontinent. It is caused by the Pigeonpea sterility mosaic virus (PPSMV), vectored by an eriophyid mite, Aceria cajani. SMD inhibits flower production and renders plants sterile. The extent of sterility depends on the cultivar and time of infection. A susceptible cultivar infected at an early stage of the growth (<45-days-old) results in 95–100% reduction in flowering and in case of late infection (>45-days-old plants) reduction in flowering range from 20–90%. Partially infected plants and a few severely infected plants produced some flowers. They form pods with normal or deformed (shrivelled) seeds. In grow-out tests only c. 70% of the seed collected from the infected plants germinated, but all these plants were free from PPSMV. Flowers and fresh pods from PPSMV (Patancheru isolate) infected pigeonpea (cv. ICP8863) were separated into sepals, petals, anthers and ovaries, and mature green pods were teased into pod coats, seed coats and cotyledons. Each of these was tested for the virus by double antibody sandwich (DAS)-ELISA using PPSMV polyclonal antibodies and penicillinase detection system. PPSMV was detected in all the floral parts and the virus concentration was highest in sepals, followed by anthers, ovaries and petals. PPSMV was detected in pod and seed coats, but not in the cotyledons. Symptoms were not apparent on flowers and pods collected from SMD affected plants. Seed transmission occurs when virus invades cotyledons. Seed-cotyledons of PPSMV infected plants were free from the virus and thus there was no seed transmission.