Developing Transcriptomic Resources for the Insect Heteropsylla cubana (Psyllidae)

The “Leucaena psyllid”, Heteropsylla cubana Crawford (Psyllidae), includes small phloem feeding insects that are notable both as pests on mimosoid legumes in the genus Leucaena and for the occurrence of bacterial endosymbionts in gut bacteriocytes that are vertically transferred from mother to offspring. All life stages of these psyllids feed from the phloem in young shoots of Leucaena, causing severely retarded growth, defoliation, and sometimes death of the plant. As a result, they severely impact the potential utility of Leucaena as an important species in tropical agroforestry. Furthermore, the low amino acid content of phloem sap has presumably led to the evolution of the bacteriocytes, which are known to help provide essential nutrients to the insect in much the same way as a legume root nodule provides nutrients to their host plant. Despite considerable interest in basic and applied research on these psyllids, the Leucaena-insect system, and the bacteriocyte-insect system, there are few genomic resources available for H. cubana. In this study, RNA-seq analysis was carried out on H. cubana individuals feeding on Leucaena leucocephala in the lab. A stranded 100bp paired-end Illumina library was sequenced on a HiSeq2500 and de novo assembled using the software suite Trinity. The total number of transcripts and the number of genes projected were calculated. The Core Eukaryotic Genes Mapping Approach (CEGMA) analysis identified 93.5 % “complete hits”, suggesting that the transcriptome has deeply sampled gene space. This resource is important for the investigation of transcriptomes being used to study resistance to and the impact of H. cubana on Leucaeana as well as studies on bacteriocyte interactions and co-evolution in H. cubana. They also provide a critical transcriptome for insect comparative transcriptomics.