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Verticillium wilt (VW), Fusarium wilt (FW) and Root-knot nematode (RKN) are the main diseases affecting cotton production. However, many reported quantitative trait loci (QTLs) for cotton resistance have not been used for agricultural practices because of inconsistencies in the cotton genetic background. The integration of existing cotton genetic resources can facilitate the discovery of important genomic regions and candidate genes involved in disease resistance. Here, an improved and comprehensive meta-QTL analysis was conducted on 487 disease resistant QTLs from 31 studies in the last two decades. A consensus linkage map with genetic overall length of 3006.59 cM containing 8650 markers was constructed. A total of 28 Meta-QTLs (MQTLs) were discovered, among which nine MQTLs were identified as related to resistance to multiple diseases. Candidate genes were predicted based on public transcriptome data and enriched in pathways related to disease resistance. This study used a method based on the integration of Meta-QTL, known genes and transcriptomics to reveal major genomic regions and putative candidate genes for resistance to multiple diseases, providing a new basis for marker-assisted selection of high disease resistance in cotton breeding.

Cotton is one of the most economically important fiber crop plants worldwide. The genus Gossypium contains a single allotetraploid group (AD) and eight diploid genome groups (A–G and K). However, the evolution of repeat sequences in the chloroplast genomes and the phylogenetic relationships of Gossypium species are unclear. Thus, we determined the variations in the repeat sequences and the evolutionary relationships of 40 cotton chloroplast genomes, which represented the most diverse in the genus, including five newly sequenced diploid species, i.e., G. nandewarense (C1-n), G. armourianum (D2-1), G. lobatum (D7), G. trilobum (D8), and G. schwendimanii (D11), and an important semi-wild race of upland cotton, G. hirsutum race latifolium (AD1). The genome structure, gene order, and GC content of cotton species were similar to those of other higher plant plastid genomes. In total, 2860 long sequence repeats (>10 bp in length) were identified, where the F-genome species had the largest number of repeats (G. longicalyx F1: 108) and E-genome species had the lowest (G. stocksii E1: 53). Large-scale repeat sequences possibly enrich the genetic information and maintain genome stability in cotton species. We also identified 10 divergence hotspot regions, i.e., rpl33-rps18, psbZ-trnG (GCC), rps4-trnT (UGU), trnL (UAG)-rpl32, trnE (UUC)-trnT (GGU), atpE, ndhI, rps2, ycf1, and ndhF, which could be useful molecular genetic markers for future population genetics and phylogenetic studies. Site-specific selection analysis showed that some of the coding sites of 10 chloroplast genes (atpB, atpE, rps2, rps3, petB, petD, ccsA, cemA, ycf1, and rbcL) were under protein sequence evolution. Phylogenetic analysis based on the whole plastomes suggested that the Gossypium species grouped into six previously identified genetic clades. Interestingly, all 13 D-genome species clustered into a strong monophyletic clade. Unexpectedly, the cotton species with C, G, and K-genomes were admixed and nested in a large clade, which could have been due to their recent radiation, incomplete lineage sorting, and introgression hybridization among different cotton lineages. In conclusion, the results of this study provide new insights into the evolution of repeat sequences in chloroplast genomes and interspecific relationships in the genus Gossypium.

In canine coronary artery preparations, the proteinase-activated receptor-2 ([PAR.sub.2]) activating peptides ([PAR.sub.2]-APs) SLIGRL-[NH.sub.2] and 2-furoyl-LIGRLO-[NH.sub.2] caused both an endothelium-dependent relaxation and an endothelium-independent contraction. Relaxation was caused at peptide concentrations 10-fold lower than those causing a contractile response. Although trans-cinnamoyl-LIGRLO-[NH.sub.2], like other [PAR.sub.2]-APs, caused relaxation, it was inactive as a contractile agonist and instead antagonized the contractile response to SLIGRL-[NH.sup.2]. RT-PCR-based sequencing of canine [PAR.sup.2] revealed a cleavage/activation (indicated by underlines) sequence (SKGR/SLIGKTDSSLQITGKG) that is very similar to the human [PAR.sup.2] sequence (R/SLIGKV). As a synthetic peptide, the canine PAR-AP (SLIGKT-[NH.sub.2]) was a much less potent agonist than either SLIGRL-[NH.sub.2] or 2-furoyl-LIGRLO-[NH.sub.2], either in the coronary contractile assay or in a Madin-Darby canine kidney (MDCK) cell [PAR.sub.2] calcium signaling assay. In the MDCK signaling assay, the order of potencies was as follows: 2-furoyl-LIGRLO-[NH.sub.2] [much greater than] SLIGRL-[NH.sub.2] = trans-cinnamoyl-LIGRLO-[NH.sub.2] [much greater than] SLIGKT-[NH.sub.2], as expected for [PAR.sub.2] responses. In the coronary contractile assay, however, the order of potencies was very different: SLIGRL-[NH.sub.2] [much greater than] 2-furoyI-LIGRLO-[NH.sub.2] [much greater than] SLIGKT-[NH.sub.2], trans-cinnamoyl-LIGRLO-[NH.sub.2] = antagonist. Because of 1) the distinct agonist (relaxant) and antagonist (contractile) activity of trans-cinnamoyl-LIGRLO-[NH.sub.2] in the canine coronary contractile assays, 2) the different concentration ranges over which the peptides caused either relaxation or contraction in the same coronary preparation, and 3) the markedly distinct structure-activity profiles for the PAR-APs in the coronary contractile assay, compared with those for [PAR.sub.2]-mediated MDCK cell calcium signaling, we suggest that the canine coronary tissue possesses a receptor system for the PAR-APs that is distinct from [PAR.sub.2] itself. protease; vascular G protein-coupled receptor