Imagining the city in lockdown: Place in the COVID-19 self-recordings of the Lothian Diary Project.

The COVID-19 pandemic brought about a profound change to the organization of space and time in our daily lives. In this paper we analyze the self-recorded audio/video diaries made by residents of Edinburgh and the Lothian counties during the first national lockdown. We identify three ways in which diarists describe a shift in place-time, or "chronotope", in lockdown. We argue that the act of making a diary for an audience of the future prompts diarists to contrast different chronotopes, and each of these orientations illuminates the differential impact of the COVID-19 lockdowns across the community.

Phylogenetic structure of Xanthomonas determined by comparison of gyrB sequences.

Previously, we have produced a phylogeny of species type strains from the plant-pathogenic genus Xanthomonas based on gyrB sequences. To evaluate this locus further for species and infraspecies identification, we sequenced an additional 203 strains comprising all the pathovar reference strains (which have defined plant hosts), 67 poorly characterized pathovars, currently classified as Xanthomonas campestris, and 59 unidentified xanthomonads. The well-characterized pathovars grouped either in clades containing their respective species type strain or in clades containing species related to Xanthomonas axonopodis. The Xanthomonas euvesicatoria, Xanthomonas perforans and Xanthomonas alfalfae species complex, Xanthomonas fuscans and Xanthomonas citri were discriminated as X. axonopodis-related clades and comprised a large proportion of unidentified strains as well as 80 pathovars representing all the X. axonopodis pathovars and many poorly characterized pathovars, greatly increasing the plant host ranges of the constituent species. Most xanthomonads from these three large clades were isolated from a taxonomically diverse range of plant hosts, including many weed species, from field systems in India, suggesting that these lineages became established and diversified in agricultural areas in this region. The majority of these xanthomonads had minimal sequence diversity, consistent with rapid and highly extensive pathovar diversification that has occurred in relatively recent times. Low-intensity farming practices may have provided conditions conducive to pathovar development, and evidence for pathovar diversification within other regional angiosperm floras is discussed. The gyrB locus was sufficiently discriminating to identify diversity within many species. Seven branches or clades were sufficiently distinct to be considered as potential novel species. This study has provided a comprehensive xanthomonad classification framework and has firmly established gyrB sequencing as a rapid and efficient identification tool.

Phylogenetic analysis of Xanthomonas species by comparison of partial gyrase B gene sequences.

The genus Xanthomonas currently comprises 27 species with validly published names that are important crop and horticultural pathogens. We have constructed a phylogram from alignment of gyrase B (gyrB) sequences for all xanthomonad species, both to indicate inter-species relatedness and as an aid for rapid and accurate species-level identification. The phylogeny indicated a monophyletic group, with X. albilineans and X. sacchari as the most ancestral species. Three species, X. hyacinthi, X. translucens and X. theicola, formed an early-branching group. Three clades were supported by high bootstrap values: group 1 comprised X. cucurbitae, X. cassavae and X. codiaei; group 2 comprised X. arboricola, X. campestris, X. populi, X. hortorum, X. gardneri and X. cynarae; group 3 contained the remaining species, within which two further clades, supported by a 100 % bootstrap value, were identified. Group 3A comprised X. axonopodis, X. euvesicatoria, X. perforans and X. melonis, together with X. alfalfae, X. citri and X. fuscans, whose names were recently validly published. Group 3B contained the monocot pathogens X. vasicola and X. oryzae. Two recently identified species, X. cynarae and X. gardneri, were poorly discriminated and were related closely to X. hortorum. Three species, X. perforans, X. euvesicatoria and X. alfalfae, had identical gyrB sequences. Partial sequencing of a further five genes from these species found only minor sequence differences that confirmed their close relatedness. Although branch lengths between species varied, indicating different degrees of genetic distinctiveness, the majority (n=21) were well-differentiated, indicating the utility of the method as an identification tool, and we now use this method for routine diagnosis of xanthomonad species.