Occurrence of mycoparasitic fungi Sphaerellopsis paraphysata on pearl millet rust pathogen, Puccinia substriata in India.


                               A mycoparasite was isolated on the rust infected pearl millet crop. It was isolated from an unusual pycnidia which was present along with the uredospores of rust. It reduced the uredial inoculum to a considerable extent. The morphology and molecular characters of the mycoparasite was studied. Its role as hyperparasite was established using Scanning Electron Micrographs, which clearly showed coiling and puncturing of uredospores of Puccinia substriata, by the mycelia of S. paraphysata. The confirmatory studies on the positive pathogenicity on rust fungi, showed a colourless septate mycelium, with an average conidial size of 9.27-12.92 ×2.55-5.87 μm and pycnidial size of 76.14-198.04×56.25-184.19 μm. The 540bp amplicon size of ITS sequence showed 96% similarity with S. paraphysata. The spore germination of Puccinia substriata on pearl millet leaves was reduced by 76%, 56%, 70% and the disease severity percentage was 13.3% on an average whereas in control it was 86.6%. The intimate association between S. paraphysata and Puccina substriata was proved by ultra microscopic structures in this investigation.

Key words : Pearl millet, Sphaerellopsis paraphysata, Mycoparasite, Rust, Characterization.

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