A saponin isolated from Agapanthus africanus differentially induces apoplastic peroxidase activity in wheat and displays fungicidal properties

作者：Cawood Maria E^*; Pretorius Johan C; van der Westhuizen Jan H; van Heerden Fanie R

来源：Acta Physiologiae Plantarum, 2015, 37(11): UNSP 246.

DOI：10.1007/s11738-015-1992-7

• Peroxidase enzyme activity
• Agapanthus africanus
• Steroidal saponin
• Antifungal activity

A spirostane with an attached trisaccharide, (25R)-5 alpha-spirostane-2 alpha, 3 beta, 5 alpha-triol 3-O-(O-alpha-L-rhamnopyranosyl-(1 -> 2)-O-(beta-D-galactopyranosyl-(1 -> 3))-beta-D-glucopyranoside), was isolated and identified from the aerial parts of Agapanthus africanus by activity-guided fractionation. Fungicidal properties of the crude extract, semi-purified fractions as well as the purified active saponin from A. africanus were screened in vitro against Fusarium oxysporum. At a concentration of 1 mg mL(-1), the crude extract and semi-purified ethyl acetate and dichloromethane fractions showed significant antifungal activity. The purified saponin inhibited the in vitro mycelial growth of F. oxysporum completely (100 %) at a concentration of 125 mu g mL(-1). Furthermore, to verify previously observed induced resistance by crude extracts of A. africanus towards leaf rust, intercellular PR-protein activity was determined in wheat seedlings following foliar application of the purified saponin at 100 mu g mL(-1). In vitro peroxidase enzyme activity increased significantly (60 %) in wheat seedlings 48 h after treatment with the purified saponin, demonstrating its role as an elicitor to activate a defence reaction in wheat.

• 出版日期2015-11