Small differences in the transcription patterns among members in the same promoter group were also observed. utilized for PCR reactions. 1471-2148-10-296-S8.DOC (36K) GUID:?07946464-35D6-496A-998D-08E07CEE6BE8 Abstract Background In most protein-coding genes, greater sequence variation is observed in noncoding regions (introns and untranslated regions) than in coding regions due to selective constraints. During characterization of genes and transcripts encoding small secreted salivary gland proteins (SSSGPs) from your Hessian take flight, we found exactly the reverse pattern of conservation in several families of genes: the non-coding areas were highly conserved, but the coding areas were highly variable. Results Seven genes from your em SSSGP-1 /em family are clustered as one inverted and six tandem repeats within a 15 kb region of the genome. Except for em SSSGP-1A2 /em , a gene that encodes a protein identical to that encoded by em SSSGP-1A1 /em , the additional six genes consist of a highly diversified, adult protein-coding region as well as highly conserved areas including the promoter, NCGC00244536 5′- and 3′-UTRs, a signal NCGC00244536 peptide coding region, and an intron. This unusual pattern of highly diversified coding areas coupled with highly conserved areas in the rest of the gene was also observed in several other groups of SSSGP-encoding genes or cDNAs. The unusual conservation pattern was also found in some of the SSSGP cDNAs from your Asian rice gall midge, but not from your orange wheat blossom midge. Strong positive selection was one of the causes traveling for diversification whereas concerted homogenization was likely a mechanism for sequence conservation. Conclusion KSHV ORF62 antibody Quick diversification in adult SSSGPs suggests that the genes are under selection pressure for practical adaptation. The conservation in the noncoding regions of these NCGC00244536 genes including introns also suggested potential mechanisms for sequence homogenization that are not yet fully recognized. This report should be useful for long term studies on genetic mechanisms involved in evolution and practical adaptation of parasite genes. Background Insect salivary glands are the main organs for generating proteins that are injected into hosts [1]. Plant-feeding bugs, especially those with sucking mouthparts, inject proteins and other substances into sponsor vegetation to facilitate mouthpart penetration, partially break down food before ingestion, and suppress flower defense [2-4]. Substances, including proteins with regulatory functions that can alter sponsor physiology, are referred to as effectors [5]. Pathogens, including bacteria, fungi, oomycetes, and nematodes, deliver numerous effector NCGC00244536 proteins into sponsor tissues [5-8]. Considerable evidence suggests that some of the salivary proteins injected into sponsor plants by bugs also act as effectors to suppress defense and/or reprogram physiological pathways of sponsor vegetation [3,5,9-12]. Gall midges (Cecidomyiidae), a large family of plant-feeding bugs, apparently secrete effectors into sponsor cells, inducing various forms of flower outgrowth (galls) and altering other aspects of sponsor physiology [13,14]. Flower galls contain a zone of “metabolic habitat changes” in which the parasite experiences a selective advantage because of enhanced nutrition and reduced flower defense [15]. Several organic compounds and enzymes injected into sponsor vegetation by galling bugs have been recognized, including amino acids, auxin, proteases, oxidases, and pectinases [13], but the general composition of the proteins delivered into sponsor vegetation by gall midges has not yet been fully characterized. The Hessian take flight, em Mayetiola destructor /em , is the most harmful insect pest of wheat worldwide [16]. Because of its importance in agriculture, intriguing behavior, ease of maintenance in tradition, and relatively well-characterized genetics, Hessian take flight is becoming a model varieties for studying insect-plant relationships [17,18]. Hessian take flight does not induce the formation of an outgrowth gall, but nutritive cells with similarity to the people inside macroscopic galls are created in the larval feeding site [19]. Larvae do not cause extensive tissue damage to sponsor plants, with their specialized mandibles making only a pair of small holes [19,20]. However, wheat vegetation become permanently and irreversibly stunted after 4-5 days of feeding by a single larva [9]. Actually if larvae are eliminated, growth of wheat seedlings cannot be restored [9,20], suggesting that larvae inject substances into sponsor plants that dramatically alter biochemical and physiological pathways of the attacked flower [21,22]. As the first step to identify some of those proteins that are injected into sponsor plants, we have previously generated several ESTs from cDNAs derived from dissected salivary glands of Hessian take flight 1st instar larvae [23,24]. The majority of the salivary gland transcripts encode small proteins (50 to 200 amino.