THE INFLUENCE OF THE HOST-PLANT ON LIPID RESERVES OF GLOBODERA-ROSTOCHIENSIS

Up to 16 fatty acids were detected in total lipids from roots and leav es of two potato cultivars, Desiree and Maris Piper, and one tomato cu ltivar, Pixie. The fatty acid profiles from roots were similar for all three cultivars and were dominated by C18:2(30-40%) and C16:0 (about 22%). The fatty acid profiles from leaves were similar for all three c ultivars and were dominated by C18:3 (about 52%). Both root and leaf l ipids contained mainly C18 fatty acids. The lipid content found in dry cysts of Globodera rostochiensis reared on different cultivars was 11 .0%, 12.8% and 9.6% for potato cvs Desiree and Foremost and tomato cv. Pixie, respectively. The total lipid comprised 74-82% neutral lipid, 14-19% non-acidic phospholipid and 4-7% free fatty acid in the three s amples. I-latched juveniles (J2) from cysts cultured on cvs Desiree an d Foremost contained 26.1% and 24.3% lipid, respectively. The total li pid comprised 77% neutral lipid, 17-18% nonacidic phospholipid and 6-7 % free fatty acid in the two samples. The fatty acid profiles of the m ain lipid classes of cysts of G. rostochiensis cultured on the three d ifferent cultivars were similar. The fatty acid composition of the mai n lipid classes of freshly hatched J2 from cysts of G, rostochiensis c ultured on the two potato cultivars differed only in their free fatty acid fractions. A comparison of the fatty acid profiles of the total l ipid of potato roots, cv. Desiree, and the total lipid of cysts of G., rostochiensis showed major differences. Root fatty acids and nematode fatty acids were 38% and 22% saturated. 10% and 44% monounsaturated an d 52% and 35% polyunsaturated, respectively. The fatty acid profile of root lipids was dominated by C16:0, C18:2 and C18:3 but the nematode lipids consisted of mainly Cls: I, C20:1 and C20:4. The differences in the fatty acids of host and nematodes indicate that G, rostochiensis is capable of fatty acid chain elongation and/or desaturation.