Authors:C. Bharathimatha, Sabitha Doraiswamy and R. Velazhahan*
Seed extracts of 50 plant species belonging to different families were evaluated for their ability to inhibit growth of Trichoderma viride in vitro. Of the various seed extracts, the seed extracts of Harpullia cupanioides (Roxb) belonging to Sapindaceae family exhibited very high antifungal activity. The seed extract of H. cupanioides strongly inhibited the growth of Rhizoctonia solani, Curvularia lunata, Colletotrichum musae and Alternaria alternata. Seed extract of H. cupanioides retained its antifungal activity even after heating at 100 °C for 10 min or autoclaving at 121 °C for 20 min. For partial purification of antifungal proteins, H. cupanioides seed extract was subjected to ammonium sulphate fractionation followed by gel filtration on Sephadex G-200 column. The fractions from sephadex G-200 were individually tested for their antifungal activity against T. viride. SDS-PAGE analysis of the fractions from Sephadex-G200 column indicated that the fractions with antifungal activity contained a 68-kDa band as well as other low molecular weight protein bands. The N-terminal amino acid sequence of the 68-kDa protein (13 residues) was determined by Edman degradation. However, comparison with sequences in the GenBank database (Swiss Prot) did not reveal any homology with known protein sequences.
Authors:C. Bharathimatha, Sabitha Doraiswamy, R. Rabindran, P. Renukadevi and R. Velazhahan
Seed extract of Harpullia cupanioides was tested against infection by Tomato spotted wilt virus (TSWV), Rice tungro virus (RTV) and Cowpea aphid borne mosaic virus (CABMV). Seed extract of H. cupanioides (10%) when sprayed on test plants 24 h before virus inoculation significantly inhibited virus infections. Percentage inhibition of TSWV in local lesion host by 10% seed extract of H. cupanioides was found to be 90.9. Pre-inoculation application of 10% seed extract of H. cupanioides provided 87.5% inhibition of CABMV infection. The seed extract (10%) sprayed rice plants recorded RTV infection of 48% as against 100% in control.