Quantification of new and archived Diaphorina citri transcriptome data using a chromosomal length D. citri genome assembly reveals the vector’s tissue-specific transcriptional response to citrus greening disease

Abstract

Background Huanglongbing (HLB) is the most serious disease of citrus. HLB is caused by the obligate, intracellular bacterium Candidatus Liberibacter asiaticus (CLas). CLas is transmitted by Diaphorina citri, the Asian citrus psyllid. Development of transmission blocking strategies to manage HLB relies on knowledge of CLas-D. citri interactions at the molecular level. Prior transcriptome analyses of CLas-infected and un-infected D. citri point to changes in psyllid biology due to CLas-infection. These studies relied on incomplete versions of the D. citri genome, lacked proper host plant controls, and/or were analyzed using different statistical approaches. Therefore, we used standardized experimental and computational approaches to identify differentially expressed genes in both CLas (+) and CLas (-) D. citri. The comparative analysis utilized the newest chromosomal length D. citri genome assembly Diaci_v3. In this work, we present a quantitative transcriptome analysis of excised heads, salivary glands, midguts and bacteriomes from CLas (+) and CLas (-) insects. Results Each organ had unique transcriptome profiles and responses to CLas infection. Though most psyllids were infected with CLas, CLas-derived transcripts were not detected in all organs. By analyzing the midgut dataset using both the Diaci_v1.1 and v3.0 D. citri genomes, we showed that improved genome assembly led to significant and quantifiable differences in RNAseq data interpretation. Conclusions Our results support the hypothesis that future transcriptome studies on circulative, vector-borne pathogens should be conducted at the tissue specific level using complete, chromosomal-length genome assemblies for the most accurate understanding of pathogen-induced changes in vector gene expression.

Quantitative Isotope-Labeled Cross-Linker Proteomics Reveals Developmental Variation in Protein Interactions and Post-Translational Modifications in Diaphorina citri, the Citrus Greening Insect Vector

“…Analysis of the role of genes, transcripts, proteins, and metabolites in C Las transmission by D. citri may reveal novel approaches to disease control. , High-throughput genome and transcriptome analysis has provided details of gene sequences and expression levels in a wide range of insect vectors. − Proteomic analyses rely on databases of proteins predicted from genomic and transcriptomic data, and application of mass spectrometry (MS) workflows to the study of vector biology has enabled the identification of proteins and metabolites that are present at high abundance in specific transmission barrier tissues or in response to experimental treatments such as host plant infection. − MS-based workflows designed to identify protein–protein interactions provide complementary data to quantitative proteomics using spectral counting, revealing details of the protein intramolecular structure. The conformation of protein complexes may enable the development of targeted strategies to block pathogen transmission by insect pests. , …”

“…7 Analysis of the role of genes, transcripts, proteins, and metabolites in CLas transmission by D. citri may reveal novel approaches to disease control. 8,9 High-throughput genome and transcriptome analysis has provided details of gene sequences and expression levels in a wide range of insect vectors. 10−12 Proteomic analyses rely on databases of proteins predicted from genomic and transcriptomic data, and application of mass spectrometry (MS) workflows to the study of vector biology has enabled the identification of proteins and metabolites that are present at high abundance in specific transmission barrier tissues or in response to experimental treatments such as host plant infection.…”