The fungus Leptosphaerulina persists in Anopheles gambiae and induces melanization

Abstract

Anopheles mosquitoes are colonized by diverse microorganisms that may impact on host biology and vectorial capacity. Eukaryotic symbionts such as fungi have been isolated from Anopheles, but whether they are stably associated with mosquitoes and transmitted transstadially across mosquito life stages or to subsequent generations remains largely unexplored. Here, we show that a Leptosphaerulina sp. fungus isolated from the midgut of An. gambiae can be stably associated with An. gambiae host and that it imposes low fitness cost when re-introduced through co-feeding. This fungus is transstadially transmitted across An. gambiae developmental stages and to their progeny. It is present in field-caught larvae and adult mosquitoes at moderate levels across geographical regions. We observed that Leptosphaerulina sp. induces a distinctive melanotic phenotype across the developmental stages of mosquito. As a eukaryotic symbiont that is stably associated with An. gambiae Leptosphaerulina sp. can be explored for paratransgenesis.

Malaria-Transmitting Vectors Microbiota: Overview and Interactions With Anopheles Mosquito Biology

“…These fungi isolates included Hyphopichia burtonii , Hyphopichia sp ., Penicillium georgiense, Periconia sp. Leptosphaerulina chartarum, Cladosporium cladosporioid, Hasegawazyma lactos, Epicoccum sp., Alternaria alternate , and Lichtheimia hyalospora ( Nattoh et al, 2021 ). Some yeast isolates, including Meyerozyma guilliermondii , Rhodotorula glutinis , were also identified in the guts of laboratory strains of An.…”

“…was shown to activate the host immune system to induce melanization (production of melanin deposits) on the fat body in An. gambiae ( Nattoh et al, 2021 ). Further knowledge regarding the interactions between host and pathogens is required to better understand how these fungi affect longevity and other mosquito life-history traits.…”