MOLECULAR EVIDENCE ON SYMBIOTIC RELATIONSHIPS BETWEEN BRACOVIRUS AND SPODOPTERA LITTORALIS (LEPIDOPTERA: NOCTUIDAE)
Poljoprivreda i Šumarstvo
Bracoviruses (BVs) from the Polydnaviridae family are symbionts of parasitic braconid wasps. BVs are used by parasitoid wasps to manipulate their lepidopteran host physiology. The virus is transmitted into the haemocoel of the host during oviposition, together with the parasitoid egg and other maternal protein secretions. Viral products encode proteins that lower host immunity; allowing the development of parasitoid wasp larvae in the host they ensure wasp survival in the lepidopteran larvae.
... idopteran larvae. The Egyptian cotton leafworm, Spodoptera littoralis (Boisd.), is an important pest that causes extensive damages in many vegetable, fodder, and fiber crops. Although resistance has been developed to different types of insecticides, chemical-based control methods are still used as a management strategy for S. littoralis. In the present study, two transcripts that are members of the C-type lectin family encoding BV proteins were annotated from a cDNA library generated from the hemolymph of the fifth instar larvae of S. littoralis. Characterizations of the nucleotide and deduced amino acid sequences of these genes approved the bracoviral deriving genes, and also showed sequence similarity to lectin proteins of a parasitoid wasp, Cotesia sp. (Hymenoptera: Braconidae). A phylogenetic analysis showed a relationship between the C-type lectins from Lepidoptera and Hymenoptera suggesting that there is bracovirus-mediated gene flux between two orders. We suggest that the symbiotic relationship between bracovirus and S. littoralis might have an important role in the benefit of wasps, resulting in a suppressed host immune system and also for the evolution process of the interacted genomes.