natural-products-in-plant-pest-management

Fungal Endophytes 229isolates in many of the world’s rainforests (Fig. 11.4; Li et al., 2001). As aninteresting spin-off to endophyte studies, ambuic acid and another endophyteproduct, terrein, have been used as models to develop new solid-stateNMR tensor methods to assist in the characterization of molecularstereochemistry of organic molecules (Harper et al., 2001).A strain of P. microspora was isolated from the endangered tree Torreyataxifolia and produces several compounds that have antifungal activity,including pestaloside, an aromatic β-glucoside, and two pyrones, pestalopyroneand hydroxypestalopyrone (Lee et al., 1995a,b). These compounds alsopossess phytotoxic properties. Other newly isolated secondary productsobtained from P. microspora (endophytic on Taxus brevifolia) include two newcaryophyllene sesquiterpenes, pestalotiopsins A and B (Pulici et al., 1996a,b),2α-hydroxydrimeninol and a highly functionalized humulane. Variation inthe amount and types of products found in this fungus depends on both theculture conditions and the original plant source from which it was isolated.Pestalotiopsis jesteri is a newly described endophytic fungal species fromthe Sepik river area of Papua New Guinea, and it produces the highly functionalizedcyclohexenone epoxides, jesterone and hydroxy-jesterone, whichexhibit antifungal activity against a variety of plant pathogenic fungi (Li andStrobel, 2001). Jesterone has subsequently been synthesized with completeretention of biological activity (Fig. 11.5; Hu et al., 2001). Jesterone is one of18HO H HCH 317H 3 C1516 141312HHH118199OH107OH56H4HO3H2COOH1Fig. 11.4. Ambuic acid, a highly functionalized cyclohexenone epoxide produced by anumber of isolates of Pestalotiopsis microspora found in rainforests around the world.OHHOHOHHHFig. 11.5. Jesterone, a cyclohexenone epoxide from Pestaliotiopsis jesteri, hasantioomycete activity.