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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Subtropical Insects and Horticulture Research » Research » Publications at this Location » Publication #182971
Title: AN EXPRESSED SEQUENCE TAG (EST) CDNA LIBRARY OF APHIS GOSSYPII ALATES

Author
item LEE, L - UNIV. OF FLORIDA
item Hunter, Wayne
item Hunnicutt, Laura

Submitted to: American Phytopathological Society
Publication Type: Proceedings
Publication Acceptance Date: 4/25/2005
Publication Date: 6/1/2005
Citation: Lee, L., Hunter, W.B., Hunnicutt, L.E., Dang, P.M. 2005. An expressed sequence tag (est) cDNA library of Aphis gossypii alates. American phytopathological society annual meeting. July 30-Aug. 3, 2005. Austin, TX.Paper No. P-579.

Interpretive Summary: Aphids are the most economically important of all insect plant disease vectors, of these the melon aphid, Aphis gossypii (Glover), is an economically important insect vector known to transmit over 50 plant viruses. Alate (winged) forms of this aphid readily disseminate with the wind in response to overcrowding or host declines and thus, are able to spread viral infection among and between fields. Potential genetic triggers of dispersal were examined using expressed sequence tags (EST), an approach that permits us to identify genes being expressed during different life stages of the aphids. For this study, a cDNA library was made from alates reared in an insectary greenhouse. We sequenced 10,000 ESTs, which were quality scored and aligned to produce a 3,900 unigene set. The protein sequences were annotated based on the biochemical function of matched sequences to known proteins in the National Center for Biotechnology Information, NCBI, genetic database. Several proteins in the library had significant identity matches to sequences in the NCBI database, including genes and proteins from alates of the brown citrus aphid, Toxoptera citricida (Kirkaldy). However, 30% of the A. gossypii unigene set had no significant match in the NCBI database. By studying the genes expressed during aphid dispersal the genetic products will aid the identification of important genes which play a key role in aphid growth, development, behavior, and pathogen-aphid interactions. By understanding the role of these genes in the disease transmission process researchers may be able to disrupt aphid dispersal thus reducing the spread of plant diseases.

Technical Abstract: The melon aphid, Aphis gossypii (Glover), is an economically important insect vector known to transmit over 50 plant viruses. Alate (winged) forms of this aphid readily disseminate with the wind in response to overcrowding or host declines and thus, are able to spread viral infection among and between fields. Potential genetic triggers of dispersal were examined using an expressed sequence tag (EST) approach in order to identify genes being expressed during the alate life stage. For this study, a cDNA library was made from alates reared in an insectary greenhouse. Large-scale single-pass, 5-prime-end sequencing was used to produce 10,000 ESTs, which were quality scored and aligned to produce a 3,900 unigene set composed of 1,017 contigs and 2,864 singletons. The putative protein transcript of each assembled sequence was annotated based on the biochemical function of matching gene sequences using BLASTX. Several sequences in the library had significant identity matches to sequences in the NCBI nr database, including ESTs from the alates of brown citrus aphid, Toxoptera citricida (Kirkaldy). However, 30% of the ESTs had no significant match in the NCBI nr database. This transcriptome survey should help in the identification of important genes which play a key role in aphid growth and development, physiology, behavior, virus-aphid interactions, and pathology.