SHYAMALAMMA, S.DIXITHA, M.2021-09-302021-09-302018-08-01https://krishikosh.egranth.ac.in/handle/1/5810176434Viola odorata (Linn.) is an important medicinal herb with cyclotides in all plant parts. Cyclotides are peptides with a wide range of biological activities such as antimicrobial and insecticidal activity. Thus, the cyclotides were extracted from leaf and petiole parts through ethanol extraction and were quantified by RP-HPLC method. Both leaf and petiole extracts of Viola odorata yielded cyclotides with a peak retention time of 23.5 min. indicating the presence of cyclotides. An assay for the antimicrobial activity of cyclotides from leaf and petiole extract of Viola odorata against late blight causing organism (Phytophthora infestans) in tomato was carried out. The cyclotides inhibited the growth of Phytophthora infestans at low concentration (10μg/mL) as compared to higher concentration (50μg/mL and 100μg/mL) used in the study. Multiplication of Viola odorata is difficult due to seed dormancy. Hence, micro-propogation protocol was standardized by using leaf and petiole explants. Surface sterilization of leaf and petioles of Viola odoratawith 1Per cent Bavistin for 45 min, 40Per cent NaOCl for 5 minutes followed by 0.1Per cent HgCl2for 1.30 minutes gave the highest percent survival of explants. Maximum callus induction from leaf was obtained in FMS media, containing 1.0mg/L BAP + 1.0mg/L TDZ, whereas callus induction from petiole was higher in FMS media, containing 0.5mg/L BAP + 0.5mg/L TDZ. Maximum number of shoots were regenerated from the callus on HMS media, comprising NA (0.5mg/L), GA3 (1.05mg/L), AgNO3 (0.42mg/L) and TDZ (2.5mg/L) with an average number of 1.50 shoots per explant.EnglishThesis