Genomic sequence analysis reveals diversity of Australian Xanthomonas species associated with bacterial leaf spot of tomato, capsicum and chilli

The genetic diversity in Australian populations of Xanthomonas species associated with bacterial leaf spot in tomato, capsicum and chilli were compared to worldwide bacterial populations. The aim of this study was to confirm the identities of these Australian Xanthomonas species and classify them in comparison to overseas isolates. Analysis of whole genome sequence allows for the investigation of bacterial population structure, pathogenicity and gene exchange, resulting in better management strategies and biosecurity

Πειραματική διερεύνηση της διαλυτότητας του διοξειδίου του άνθρακα σε υδατικά διαλύματα ανθρακικού καλίου με πρόσθετες αμίνες και αμινοξέα

Recent studies into the distribution of Xanthomonas species causing Bacterial Leaf Spot (BLS) in Australian solanaceous crops detail varied genomic profiles that may influence pathogenicity. These genomic studies are expanded upon here by reporting the pathogenicity, race and copper tolerance of the previously sequenced Xanthomonas strains. Capsicum (Yolo Wonder), tomato (Grosse Lisse) and differential lines of capsicum (Early Cal-Wonder) were used to determine pathogenicity and race. Copper tolerance of 44 Xanthomonas strains was measured by observing bacterial growth on copper sulphate amended media. Protein sequence associated with these traits was detected using genomic analysis and compared using protein alignments. Only strains of X. euvesicatoria (16 strains) were found to be pathogenic on both tomato and capsicum. These were determined to be race 4 and 9. High copper tolerance was detected in the majority of Xanthomonas strains tested. Multiple copper resistance and avirulence proteins were detected in genomic sequence. Relatively few of these were associated with plasmid sequences. The genomic basis for copper tolerance was determined to be complex, as the tolerance thresholds did not directly correlate with gene number or presence. Similarly, pathogenicity of the strains was also not always clearly linked with presence or absence of specific Avr genes. This study highlights the need for detailed and ongoing investigations into the function of these proteins and how they produce the phenotypes that affect crop production

Sugarcane (Saccharum X officinarum): A Reference Study for the Regulation of Genetically Modified Cultivars in Brazil

Global interest in sugarcane has increased significantly in recent years due to its economic impact on sustainable energy production. Sugarcane breeding and better agronomic practices have contributed to a huge increase in sugarcane yield in the last 30 years. Additional increases in sugarcane yield are expected to result from the use of biotechnology tools in the near future. Genetically modified (GM) sugarcane that incorporates genes to increase resistance to biotic and abiotic stresses could play a major role in achieving this goal. However, to bring GM sugarcane to the market, it is necessary to follow a regulatory process that will evaluate the environmental and health impacts of this crop. The regulatory review process is usually accomplished through a comparison of the biology and composition of the GM cultivar and a non-GM counterpart. This review intends to provide information on non-GM sugarcane biology, genetics, breeding, agronomic management, processing, products and byproducts, as well as the current technologies used to develop GM sugarcane, with the aim of assisting regulators in the decision-making process regarding the commercial release of GM sugarcane cultivars

Identification of Xanthomonas species associated with bacterial leaf spot of tomato, capsicum and chilli crops in eastern Australia

Several species of Xanthomonas cause bacterial leaf spot, a disease that affects solanaceous crops worldwide. The diversity of 64 Australian isolates of Xanthomonas spp. associated with bacterial leaf spot in tomato, capsicum and chilli crops in eastern Australia was determined using multi-locus sequence analysis of atpD, dnaK, efp and gyrB genes, species-specific PCR assays and biochemical analyses. At least five species of Xanthomonas associated with bacterial leaf spot were identified in Australian tomato, capsicum and chilli crops and their pathogenicity assessed. Phylogenetic and biochemical analyses identified X. euvesicatoria, X. perforans and X. vesicatoria as the most frequently recovered pathogenic species. Non-pathogenic and weakly pathogenic species were also identified. The suitability of the identification methods used and the implications of the detection of these species will be discussed