Temperature Effects on Expression Levels of hsp Genes in Eggs and Second-Stage Juveniles of Meloidogyne hapla Chitwood, 1949.

Meloidogyne hapla is one of the most important nematode pathogens. It is a sedentary, biotrophic parasite of plants that overwinters in the soil or in diseased roots. The development of M. hapla is temperature dependent. Numerous studies have been performed on the effect of temperature on the development of M. hapla , but only a few of them analyzed the heat shock protein ( hsp ) genes. The aim of the study was to perform expression profiling of eight hsp genes ( Mh-hsp 90, Mh-hsp 1, Mh-hsp 4, Mh-hsp 6, Mh-hsp 60, Mh-dnj 19, Mh-hsp 43, and Mh-hsp 12.2) at two development stages of M. hapla , i.e., in eggs and second-stage juveniles (J2). The eggs and J2 were incubated under cold stress (5 °C), heat stress (35 °C, 40 °C), and non-stress (10 °C, 20 °C, and 30 °C) conditions. Expression profiling was performed by qPCR. It was demonstrated that only two genes, Mh-hsp 60 and Mh-dnj 19, have been upregulated by heat and cold stress at both development stages. Heat stress upregulated the expression of more hsp genes than cold stress did. The level of upregulation of most hsp genes was more marked in J2 than in eggs. The obtained results suggest that the Mh-hsp 90 and Mh-hsp 1 genes can be used as bioindicators of environmental impacts on nematodes of the Meloidogyne genus.