Diversity and phylogenetic analysis of endosymbionts fromTrioza erytreae(Del Guercio) and its parasitoids in Kenya

Abstract

The African citrus triozid (ACT), Trioza erytreae (Del Guercio), is the primary vector of Candidatus Liberibacter africanus (CLaf), the causative agent of Africa citrus greening disease (ACGD). This study evaluates the diversity of ACT parasitoids and further characterizes endosymbionts associated with both T. er y treae and its parasitoids that could be used as biological control agents of T. er y treae and management of ACGD. Mitochondrial cytochrome oxidase I gene was used to reconstruct T. er y treae and its parasitoids phylogeny, while 16S rRNA gene was used for the bacterial phylogeny. One well-supported clade of ACT was detected within the Triozidae phylogeny, while the parasitoid species clustered into four groups within eulophid and encyrtid phy-logeny. The phylogenetic result of parasitoids was supported by morphological iden-tification where five different parasitoid species could be identified, that is Tamarixia dryi, Psyllaephagus pulvinatus, Tetrastichus sp., Aphidencyrtus cassatus and Charipinespecies. Moreover, four eubacterial symbionts (Wolbachia, Rickettsia, Arsenophonusand Candidatus Liberibacter sp.) were detected in T. er y treae and three symbionts (Wolbachia, Rickettsia and Cardinuim) in the parasitoid specimens. Maximum likeli-hood phylogenetic inferences clustered the identified eubacterial symbionts within α and γ proteobacteria subdivisions. Phylogenetic inferences of 16S rRNA gene se-quences indicated that Wolbachia strains from ACT and the parasitoids did not form a single monophyletic clade; however, both clustered within Supergroup B. The im-pacts of these parasitoid species and endosymbionts on ACT are still unknown, but their occurrence and broad distribution indicate the possibility of future use for con-trol of T. er y treae.