The peptidoglycan recognition proteins PGRPLA and PGRPLB regulate Anopheles immunity to bacteria and affect infection by Plasmodium

Peptidoglycan recognition proteins (PGRPs) form a family of immune regulators that is conserved from insects to mammals. In the malaria vector mosquito Anopheles coluzzii , the peptidoglycan receptor PGRPLC activates the Imd pathway limiting both t he microbiota load and Plasmodium infection. Here, we carried out an RNAi screen to examine the rol e of all seven Anopheles PGRPs in infections with Plasmodium berghei and Plasmodium falciparum . We show that, in addition to PGRPLC, PGRPLA and PGRPS2/S3 also participate in antiparas itic defenses, and that PGRPLB promotes mosquito permissiveness to P. falciparum . We also demonstrate that following a mosquito blood feeding, which promotes growth of the gut microbiota, PGRPLA and PGRPLB positively and negatively regulate the activation of the Imd pathway, respective ly. Our data demonstrate that PGRPs are important regulators of the mosquito epithelial immunity and vector comp etence