Comparative genomics reveals evolutionary drivers of the dietary shift in Hemiptera.

Hemiptera insects exhibit a close relationship to plants and demonstrate a diverse range of dietary preferences, encompassing phytophagy as the predominant feeding habit while a minority engages in carnivorous or haematophagous behaviour. To counteract the challenges posed by phytophagous insects, plants have developed an array of toxic compounds, causing significant evolutionary selection pressure on these insects. In this study, we employed a comparative genomics approach to analyse the expansion and contraction of gene families specific to phytophagous insect lineages, along with their adaptive evolutionary traits, utilising representative species from the Hemiptera order. Our investigation revealed substantial expansions of gene families within the phytophagous lineages, especially in the Pentatomomorpha branch represented by Oncopeltus fasciatus and Riptortus pedestris. Notably, these expansions of gene families encoding enzymes are potentially involved in hemipteran-plant interactions. Moreover, the adaptive evolutionary analysis of these lineages revealed a higher prevalence of adaptively evolved genes in the Pentatomomorpha branch. The observed branch-specific gene expansions and adaptive evolution likely contribute significantly to the diversification of species within Hemiptera. These results help enhance our understanding of the genomic characteristics of the evolution of different feeding habits in hemipteran insects.

Development of Race-Specific SCAR Markers for Detection of Chinese Races CYR32 and CYR33 of Puccinia striiformis f. sp. tritici.

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici, is a devastating disease in China. Races CYR32 and CYR33 have been predominant in the recent P. striiformis f. sp. tritici population. To develop molecular markers for these races, initially 86 isolates, most of which were collected in 2007 throughout China, were tested on the set of wheat genotypes for differentiating Chinese P. striiformis f. sp. tritici races, and their genomic DNA were amplified with 94 random amplified polymorphic DNA (RAPD) primers. Twelve isolates were identified as CYR33, 14 as CYR32, and 60 as 13 other races. A 320-bp band was identified to be associated with CYR32 with primer S1271 (5'-CTTCTCGGTC-3'), and a 550-bp band was identified to be specific to CYR33 with primer S1304 (5'-AGGAGCGACA-3'). The two bands were cloned and sequenced. Based on the sequences, sequence characterized amplified region (SCAR) markers CYR32sp1/sp2 and CYR33sp1/sp2 were developed to differentiate CYR32 and CYR33, respectively, from other races. The SCAR markers were validated with DNA samples from wheat leaves inoculated with selected isolates from the 86 isolates and urediniospore DNA samples from an additional 63 isolates collected from 2006 to 2009. The detection of CYR32 and CYR33 with the SCAR markers was completely consistent with the results of the race identification with the set of differential wheat genotypes. Thus, the markers are highly reliable for identification of the two races.

[Role of Treg/Th17 cells and related cytokines in Graves' ophthalmopathy].

OBJECTIVE: To explore the role of CD4⁺ CD25⁺ Foxp3⁺ Treg/CD4⁺ IL-17A(+)Th17 cells and the related cytokines in Graves' ophthalmopathy. METHODS: Based on clinical activity scores (CAS), we divided patients with untreated Graves' ophthal- mopathy into active group (AGO group with CAS ≥ 3 (15 cases) and non-active group (NGO group) with CAS<3 (15 cases), with another 15 patients with untreated Graves' disease free of eye symptoms (GD group) and 15 normal subjects as controls. Peripheral venous blood Treg/Th17 cell ratio was determined using flow cytometry. RT-PCR was used to detect the mRNA expression levels of Treg-specific transcription factor Foxp3 and Th17-specific transcription factor RORγt. Enzyme-linked immunosorbent assay (ELISA) was used to detect the serum levels of Th17 cell-related cytokines (IL-17A, IL-23, and IL-6) and Treg-related cytokines (TGF-ß, IL-10, and IL-35). RESULTS: Compared with the normal subjects, the patients in GD, NGO, AGO groups all showed significantly increased Th17 cell count (P<0.05), which was the highest in AGO group. RT-PCR results revealed significantly increased RORγt in GD, NGO, and AGO groups, also the highest in AGO group. Serum IL-17A, IL-23, and IL-6 levels all showed significant increments in GD, NGO, and AGO groups (P<0.05), especially in AGO group. Among the Treg-related cytokines, TGF-ß and IL-35 levels decreased (P<0.05) but IL-10 increased significantly (P<0.05) in GD, NGO, AGO groups. CONCLUSION: Decreased immunosuppressive capacity of Treg cells can be an important factor in the pathogenesis of Graves' ophthalmopathy. Th17 cells may also participate in the occurrence and progression of Graves' ophthalmopathy and can serve along with related cytokines as novel indicators of the disease activity. Impaired Treg/Th17 balance may importantly contribute to the occurrence of Graves' ophthalmopathy.

Discovery of multiple IGS haplotypes within genotypes of Puccinia striiformis.

In a search for specific molecular markers for population analysis of Puccinia striiformis f. sp. tritici, the ribosomal DNA (rDNA) intergenic spacer (IGS) 1 region (rDNA-IGS1, between the 28S and the 5S rDNA genes) was amplified, cloned, and sequenced. It was found to exhibit multiple bands and length polymorphism. Surprisingly, single isolates were found to possess between three to five different IGS1 haplotypes. Bands were cloned and sequenced, and two highly variable regions (α and ß) were found between conserved regions, with repeat units interspersed in both types of regions. There were 14 different repeat units, and these were sometimes grouped further into four combinations of repeat units, with a few individual nucleotides (A or C) inserted between the repeats. Among three geographically dispersed isolates, the variable region α was divided into eight types, and the variable region ß was divided into two types based on repeat units. Most of the 14 repeat units were shared by the variable and the conserved regions. Among the three isolates, there were a total of 12 IGS1 haplotypes, but some of these were shared between isolates such that there were only eight unique haplotypes. The occurrence of multiple haplotypes within single isolates may be useful for analyzing the population structure, tracking the origin of annual epidemics and providing insights into evolutionary biology of this pathogen.