The total lipid content of the dry weight of whole
cysts and 2nd-stage juveniles (J2) of Globodera
rostochiensis was 17·1%
in dry cysts, 20·9% in cysts soaked in distilled water (DW),
20·3% in cysts that had been in potato root diffusate (PRD)
for 7 days, 7·3% in cysts that had been in PRD for 28 days
and 29·2% for hatched J2. The fatty acid composition of the
total lipid did not differ between dry cysts, cysts in DW and
cysts in PRD for 7 days. However, major differences in the
fatty acid composition of all lipid classes were found between
rehydrated cysts in PRD and freshly hatched J2. After
hatching, the degree of saturation and the percentage of
monounsaturated fatty acids decreased and the percentage of
polyunsaturated fatty acids increased considerably, especially
in the free fatty acid fraction, where C20[ratio ]1 showed an
8-fold decrease and C20[ratio ]4 a 33-fold increase. There was a
difference in the fatty acid composition of cysts in PRD for 7
days and cysts in PRD for 28 days (after most of the J2 had
hatched); with increased time in PRD the percentage of
polyunsaturated fatty acids increased and the percentage of
monounsaturated fatty acids decreased in all lipid classes.
Differences in the fatty acid profiles between cysts in PRD for
28 days and hatched J2 were found mainly in the free fatty
acid and the non-acidic phospholipid fractions. The free fatty
acid fraction of the cysts was dominated by monounsaturated
fatty acids (52%), whereas the same fraction of hatched J2
contained large amounts of polyunsaturated fatty acids (60%).
These polyunsaturated fatty acids, especially C20[ratio ]4,
might play an important part in nematode–plant
interactions during infection.
Comparison of free fatty acid composition between low-fat and full-fat goat milk cheeses stored for 3 months under refrigeration