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Quantitative trait locus mapping of resistance to turnip yellows virus in Brassica rapa and Brassica oleracea and introgression of these resistances by resynthesis into allotetraploid plants for deployment in Brassica napus.

Fri, 28 Jan 2022 10:09:06 GMT

Greer, Shannon F., Hackenberg, Dieter, Gegas, Vasilis, Mitrousia, Georgia, Edwards, David, Batley, Jacqueline, Teakle, Graham R., Barker, Guy C. and Walsh, John A

Turnip yellows virus (TuYV) is aphid-transmitted and causes considerable yield losses in oilseed rape (OSR, Brassica napus, genome: AACC) and vegetable brassicas. We report the identification, characterisation, and mapping of TuYV resistance in the diploid progenitor species of OSR, Brassica rapa (genome: AA), and Brassica oleracea This is the first report of TuYV resistance mapped in the Brassica C genome and of an allotetraploid AACC line possessing dual resistance to TuYV originating from both of its progenitors. The introgression into OSR can now be accelerated, utilising marker-assisted selection, and this may reduce selection pressure for TuYV isolates that are able to overcome existing sources of resistance to TuYV.

Frontiers in Plant Science. December 2021

First report of Turnip yellows virus in Brazil

Fri, 28 Jan 2022 10:07:40 GMT

S.F. Greer, M.J. Newbert, L.K. Rodrigues, A.M. Oliveira, A.L.R. Chaves, R.F. Calegario, G.C Barker, M. Eiras, J.A. Walsh

This is the first report of TuYV in Brazil. The finding has been reported to the Ministry of Agriculture of Brazil (MAPA), which approved the notification (SEI process 21052.012367/2021-73, 66/2021/DSV/SDA). Further work is required to determine the distribution and prevalence of TuYV and its impact on brassica cultivation in Brazil.

New Disease Reports. October 2021

The Evolutionary History of Wild, Domesticated, and Feral Brassica oleracea (Brassicaceae)

Wed, 18 Aug 2021 08:18:00 GMT

Makenzie E Mabry, Sarah D Turner-Hissong, Evan Y Gallagher, Alex C McAlvay, Hong An, Patrick P Edger, Jonathan D Moore, David AC Pink, Graham R Teakle, Chris J Stevens, Guy Barker, Joanne Labate, Dorian Q Fuller, Robin G Allaby, Timothy Beissinger, Jared E Decker, Michael A Gore, & J Chris Pires

Understanding the evolutionary history of crops, including identifying wild relatives, helps to provide insight for conservation and crop breeding efforts. Using newly generated RNA-seq data for a diversity panel of 224 accessions, which represents 14 different B. oleracea crop types and nine potential wild progenitor species, we integrate phylogenetic and population genetic techniques with ecological niche modeling, archaeological, and literary evidence to examine relationships among cultivars and wild relatives to clarify the origin of this horticulturally important species. Our analyses point to the Aegean endemic B. cretica as the closest living relative of cultivated B. oleracea, supporting an origin of cultivation in the Eastern Mediterranean region

Molecular Biology & Evolution. June 2021

Characterisation of turnip mosaic virus isolates reveals high genetic variability and occurrence of pathotype 1 in Brazil

Wed, 19 May 2021 07:59:00 GMT

Leilane Karam Rodrigues, Alexandre Levi Rodrigues Chaves, Elliot Watanabe Kitajima,, Renata Faier Calegario,, Katia Regiane Brunelli, Fabio Nascimento da Silva, Ricardo Harakava, John Anthony Walsh & Marcelo Eiras

Turnip mosaic virus (TuMV) infects many plant species, being the only potyvirus able to infect brassicas. Despite being considered one of the most important viruses infecting brassicas worldwide, there is little information on this virus in the Neotropical region. Aiming to fill in this gap and advance knowledge on occurrence, genetic variability, and biological aspects of TuMV in Brazil, 40 isolates were identified and characterised. Our diversity analysis suggest that a strong negative selection is acting on polyprotein coding region. We confirmed that Brazilian TuMV isolates showed high variability, which together with their ability to infect wild brassicas and to circumvent resistance genes highlight their genetic and epidemiological potential incausing damages in cultivated species of brassicas andother crops in Brazil.

European Journal of Plant Pathology. April 2021

Identification and Expression of Secreted In Xylem Pathogenicity Genes in Fusarium oxysporum f. sp. pisi

Mon, 17 May 2021 07:52:21 GMT

Sascha Jenkins, Andrew Taylor, Alison C Jackson, Andrew D Armitage, Helen J Bates, Andrew Mead, Richard J Harrison and John P Clarkson

Fusarium oxysporum is a soilborne fungal plant pathogen responsible for causing disease in many economically important crops with “special forms” (formae speciales) adapted to infect specific plant hosts. F. oxysporum f. sp. pisi (FOP) is the causal agent of Fusarium wilt disease of pea.. The main aim of this work was to characterise F. oxysporum isolates collected from diseased peas in the United Kingdom as well as FOP isolates obtained from other researchers representing different races through sequencing of a housekeeping gene and the presence of Secreted In Xylem (SIX) genes, which have previously been associated with pathogenicity in other F. oxysporum f. spp. F. oxysporum isolates from diseased United Kingdom pea plants possessed none or just one or two known SIX genes with no consistent pattern of presence/absence, leading to the conclusion that they were foot-rot causing isolates rather than FOP.

Frontiers in Microbiology. April 2021

Contrasting Responses of Rhizosphere Bacterial, Fungal, Protist, and Nematode Communities to Nitrogen Fertilization and Crop Genotype in Field Grown Oilseed Rape (Brassica napus)

Mon, 17 May 2021 07:51:00 GMT

Emma Picot, Chris C Hale, Sally Hilton, Graham Teakle, Hendrik Schafer, Yong-Ju Huang, Sarah Perryman, Jon S West and Gary D Bending

The rhizosphere microbiome is considered to play a key role in determining crop health. However, current understanding of the factors which shape assembly and composition of the microbiome is heavily biased toward bacterial communities, and the relevance for other microbial groups is unclear. Furthermore, community assembly is determined by a variety of factors and their relative importance and interactions remain to be elucidated. We investigated the impact of nitrogen fertilization on rhizosphere bacterial, fungal, nematode and protist communities of 10 contrasting oilseed rape genotypes in a field experiment. We found significant differences in the composition of bacteria, fungi, protist and nematode communities between the rhizosphere and bulk soil. We conclude that under field conditions soil and rhizosphere nutrient stoichiometry and crop genotype are key factors determining crop health by influencing the infection of roots by pathogenic and mutualistic fungal communities, and the connectivity and stability of rhizosphere microbiome interaction networks.

Frontiers in Sustainable Food Systems. April 2021

Identification of microbial signatures linked to oilseed rape yield decline at the landscape scale

Wed, 10 Feb 2021 08:47:00 GMT

Sally Hilton, Emma Picot, Susanne Schreiter, David Bass, Keith Norman, Anna E. Oliver, Jonathan D. Moore, Tim H. Mauchline, Peter R. Mills, Graham R. Teakle, Ian M. Clark, Penny R. Hirsch, Christopher J. van der Gast & Gary D. Bending

The plant microbiome plays a vital role in determining host health and productivity. Here we investigated landscape scale rhizosphere microbial assembly processes in oilseed rape (OSR) which suffers from yield decline associated with the frequency it is grown in rotations. By including 37 conventional farmers’ fields with varying OSR rotation frequencies, we present an innovative approach to identify microbial signatures characteristic of microbiomes which are beneficial and harmful to the host. We show that at the landscape scale, OSR crop yield is governed by interplay between complex communities of both pathogens and beneficial biota which is modulated by rotation frequency. Our comprehensive study has identified signatures of dysbiosis within the OSR microbiome, grown in real-world agricultural systems, which could be used in strategies to promote crop yield.

Microbiome. January 2021

The carbon footprint of waste streams in a UK hospital

Mon, 11 Jan 2021 09:05:39 GMT

Chantelle Rizan, Mahmood F. Bhutta, Malcom Reed, Rob Lillywhite

The aim of this study was to estimate and compare the carbon footprint of hospital waste streams. We estimate that the carbon footprint per t of hospital waste was lowest when it is recycled (21–65 kg CO₂e), followed by low temperature incineration with energy from waste (172–249 kg CO₂e). When the waste was additionally decontaminated using an autoclave prior to low temperature incineration with energy from waste, the carbon footprint was increased to 569 kg CO₂e. The highest carbon footprint was associated with the disposal of waste via high temperature incineration (1074 kg CO₂e/ t. In conclusion, it is possible to use the carbon footprint of hospital waste streams to derive emission factors for specific waste disposal options. This may inform the optimal processing of healthcare waste in the future.

Journal of Cleaner Production. December 2020

John Walsh publications

Wed, 06 Jan 2021 09:00:00 GMT

Sequence analysis of 43-year old samples of Plantago lanceolata show that Plantain virus X is synonymous with Actinidia virus X and is widely distributed

J Hammond, I Adams, A Fowkes, S McGreig, M Botermans, J van Oorspronk, M Westenberg, M Verbeek, A Dullemans, C Stijger, A Blouin, S Massart, K de Jonghe, M Heyneman, J Walsh, A Fox

Plantain virus X was first recognized by the International Committee on Taxonomy of Viruses (ICTV) as a species in the genus Potexvirus in 1982. However, because no sequence was available for plantain virus X (PlVX), abolishing the species was proposed to the ICTV in 2015. Here we report the full genome sequencing of two original isolates of PlVX, which have demonstrated the virus to be synonymous to Actinidia virus X a species previously reported from kiwifruit (Actinidia sp.) and blackcurrant (Ribes nigrum). This report additionally presents novel data on the distribution and diversity of PlVX.

Plant Pathology. November 2020

Confirmation of Radish Isolate of Turnip mosaic virus in India through biological and serological evidences.

Shelley Kappoor, Anil Handa, John A Walsh, Rajnish Sharma

Turnip mosaic virus is one of the limiting factors for declining oil content in brassica. The present studies were therefore conducted to confirm the presence of this important virus in brassica through biological and serological assays. A radish isolate of Turnip mosaic virus has been identified on the basis of biological and serological assays and results obtained for screening of brassica germplasm against Turnip mosaic virus are expected to help in ascertaining the sources of resistance against this virus.

Plant Pathology Journal. November 2020

Cordycepin, a metabolite of Cordyceps militaris, reduces immune-related gene expression in insects

Mon, 02 Nov 2020 13:58:28 GMT

Victoria C Woolley, Graham R Teakle, Gillian Prince, Cornelia Moor, David Chandler

Hypocrealean entomopathogenic fungi (EPF) are natural regulators of insect populations in terrestrial environments. Their obligately-killing life-cycle means that there is likely to be strong selection pressure for traits that allow them to evade the effects of the host immune system. In this study, we quantified the effects of cordycepin on insect susceptibility to EPF infection and on insect immune gene expression. The results suggest that cordycepin has potential to act as a suppressor of the immune response during fungal infection of insect hosts.

Journal of Invertebrate Pathology. October 2020

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