Title: Gene Expression in Two Leafhopper Vectors of Pierces Disease of Grapes, Glassy-Winged Sharpshooter and Blue-Green Sharpshooter (Hemiptera: Cicadellidae) Authors
Submitted to: Florida Entomological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: July 20, 2006
Publication Date: July 24, 2006
Citation: Hunter, W.B., Katsar, C.S. 2006. Gene expression in two leafhoper vectors of Pierces Disease of Grapes, Glassy-Winged Sharpshooter and Blue-green Sharpshooter (Hemiptera: Cicadellidae [abstract]. Joint Proceedings of the 89th Annual meeting and 6th International Caribbean Conference of the Florida Entomological Society. Paper No. DSP-11. Technical Abstract: Production of a unigene set identified the putative functions of over 350 transcripts from two leafhopper species (Hemiptera: Cicadellidae) which vector the plant infecting bacterium, Xylella fastidiosa. Genetic similarities between the glassy-winged sharpshooter, Homalodisca coagulata, and the blue-green sharpshooter, Graphocephala atropunctata, provide insights into the genetics which permits these insects to acquire and transmit Pierce’s Disease of grapes, as well as leading to a better understanding of the biology and pathogen relationships, particularly those related to: feeding, disease transmission, and the development of insecticide resistance. We conducted a in silico analyses of two cDNA datasets produced from large-scale 5' end sequencing projects of adult leafhoppers. Similar expressed sequence tag (EST) projects on other insects have provided valuable information on insect biology. The growing database in GenBank of ESTs from insects has relatively few genes from leafhoppers. We have produced the first public data set of ESTs from the GWSS and BGSS. Approximately 8,000 cDNA’s from GWSS and 5,900 from BGSS were sequenced, post alignments resulted in about 4,450 high-quality sequences, including both contiguous sequences and singlets, with a minimum 200 bases at a Phred 20 quality score. The putative protein transcript of each assembled sequence was annotated based on the biochemical function of matching gene sequences using BLASTX, TBLASTX, and BLASTN analyses, GenBank, nr ESTdb. The subsequent unigene set produced 358 sequences which had significant identities with homologous genes in the GenBank’s database, E=value e'10. The ability to identify the putative functions of these transcripts provides valuable leads on which genes to select for further examination. Many of these function in egg development, such as Vitellogenin, and in the development of insecticide resistance, Glutathione-s-transferase, and P450’s. The results from this study on leafhopper gene expression produced a data set that advances research efforts in the identification of genes and physiological processes of leafhoppers of economic importance. The knowledge produced concerning these genes and proteins now enables functional genomic studies to be conducted to advance our understanding of disease transmission and which focuses on the development of new management strategies to reduce plant disease spread and leafhopper populations.