Defense response of Eucalyptus camaldulensis against black spot pathogen of Pisum sativum.

Ascochyta pisi induces leaf spot in Pisum sativum . Currently A . pisi was found pathogenic against 4 pea varieties. Ten concentrations of Eucalyptus camaldulensis leaf extract and its 7 fractionations were appraised for antifungal activity against A . pisi . The highest concentration revealed 78% suppression in growth. Fractionation was carried out successively with n-hexane, Chloroform, Ethyl acetate and n-Butanol. In in vivo bioassays, all the solvent fractions particularly n-Butanol controlled pathogen efficiently on all varieties. In RT-PCR, all genes were expressed in control and treated plants of Greenfeast but the intensity of gene 2 and 8 was upregulated in treated plants. n-Butanol induced the over expression of gene 3 and 7 in Meteor. Then, in native PAGE Glu 1 was the glucanase isozyme, detected only in variety Greenfeast. Control plants of Rondo showed Glu 2 and 3, while its treated plants had Glu 1, Glu 2, Glu 3 and Glu 4. [ABSTRACT FROM AUTHOR]