Osmotic responses of different strains of Steinernema carpocapsae

A solution consisting of a mixture of glycerol and fortified artificial seawater was used to induce partial anhydrobiosis at 15°C in different strains of Steinernema carpocapsae. All the strains tested were tolerant to the osmotic solution and the survival and infectivity of the nematodes were not influenced. The osmotic treatment greatly improved heat tolerance of all the tested strains but the heat tolerance of S. carpocapsae MR7 was significantly poorer than that of the other strains. This method could be used to induce S. carpocapsae into partial anhydrobiosis and thereby improve storage of the nematodes. Expression patterns of stress-related genes after osmotic treatment were compared in a heat tolerant strain (All) and a more heat sensitive strain (MR7) after induction of anhydrobiosis. Differences in gene expression after induction of anhydrobiosis between strain MR7 and All were observed that may be related to differences in subsequent heat tolerance.