Metarhizium anisopliae, a fungal pathogen of terrestrial arthropods, kills the aquatic larvae of Aedes aegypti, the vector of dengue and yellow fever. The fungus kills without adhering to the host cuticle. Ingested conidia also fail to germinate and are expelled in fecal pellets. This study investigates the mechanism by which this fungus adapted to terrestrial hosts kills aquatic mosquito larvae. Genes associated with the M. anisopliae early pathogenic response (proteinases Pr1 and Pr2, and adhesins, Mad1 and Mad2) are upregulated in the presence of larvae, but the established infection process observed in terrestrial hosts does not progress and insecticidal destruxins were not detected. Protease inhibitors reduce larval mortality indicating the importance of proteases in the host interaction. The Ae. aegypti immune response to M. anisopliae appears limited, whilst the oxidative stress response gene encoding for thiol peroxidase is upregulated. Cecropin and Hsp70 genes are downregulated as larval death occurs, and insect mortality appears to be linked to autolysis through caspase activity regulated by Hsp70 and inhibited, in infected larvae, by protease inhibitors. Evidence is presented that a traditional host-pathogen response does not occur as the species have not evolved to interact. M. anisopliae retains pre-formed pathogenic determinants which mediate host mortality, but unlike true aquatic fungal pathogens, does not recognise and colonise the larval host.

The experiment was conducted in the winter agricultural season 2020 in the greenhouses of the Al-Fares Company in Al-Zubair district, with the aim of investigating one of the important genes responsible for tolerating Armenian cucumber for stress conditions, which is the gene (glutathione S-transferase zeta class-like) in 21 Armenian cucumber cultivars. Isolation of RNA from leaves after 100 days of cultivation at the saline level 5 dSm−1, as well as a control treatment of 1 dSm−1and studying their gene expression using RT-qPCR (Real Time-quantitative Polymerase Chain Reaction) technique. The results showed the excelled of the cultivars under the influence of salt stress, Egypt, Babylon, Mosul (Carmelis), Kirkuk, Diyala and Karbala, as they gave the highest expression of their gene expression (25.12, 21.87, 19.04, 21.87, 19.04 and 20.40), respectively, so they can be considered salt-tolerant cultivars. This is because the expression values for the gene (glutathione S-transferase zeta class-like) were high compared to the rest of the cultivars. As for the cultivars whose sensitivity to salinity was confirmed by the experiment, they are Iranian (Ghani), Italian, Baghdad and Amara. These cultivars gave the lowest gene expression values (2.73, 4.46, 4.14 and 3.49), respectively.