Latest Publications
Quantifying integrated pest management adoption in food horticulture
Jennifer Byrne, Robert Lillywhite, Henry Creissen, Fiona Thorne, Lael Walsh
Integrated Pest Management (IPM) is a crop health paradigm offering a framework for sustainable pest management. To optimise adoption it is necessary to understand how growers use IPM, to identify measures lagging in uptake or suitability for uptake and to explore limitations to both. This study has quantified IPM adoption using Irish food horticulture as a case study, through the development and application of an IPM metric based on field, protected and top fruit production systems. While our results demonstrated that IPM has been adopted, it also suggested that there is room for improvement. This presentation of an IPM measurement instrument for temperate horticulture systems provides the means to benchmark IPM performance and chart cumulative progress. This is useful to policy makers and IPM stakeholders to compare performance on a national and cross-national basis with a view to refining best practice, while defining specific components of IPM for improvement.
Stephen Parnell Publications
Assessing delimiting strategies to identify the infested zones of quarantine plant pests and diseases
Koh, Joshua, Cunnifee, Nik and Parnell, Stephen
Developing epidemiological preparedness for a plant disease invasion: Modelling citrus huánglóngbìng in the European Union
Huánglóngbìng (HLB) is a bacterial disease of citrus that has significantly impacted Brazil and the United States, although citrus production in the Mediterranean Basin remains unaffected. By developing a mathematical model of spread in Spain, we tested surveillance and control strategies before any future HLB entry in the EU. We found while some citrus production might be maintained by roguing, this requires extensive surveillance and significant chemical control, perhaps also including testing of psyllids (which spread the pathogen) for bacterial DNA. Our work highlights the key importance of early detection (including asymptomatic infection) and vector control for HLB management.
Controlling endemic foot-and-mouth disease: Vaccination is more important than movement bans. A simulation study in the Republic of Turkey
Glen Guyver-Fletcher, Erin E. Gorsich, Chris Jewell, Michael J. Tildesley
In this article we present a spatially-explicit stochastic metapopulation model to simulate the spread and control of foot-and-mouth disease (FMD) in an endemic setting. We parameterise and validate the model using detailed outbreak data from the Republic of Turkey, 2001–2012. Subsequently, we assess the efficacy of ring vaccination, mass vaccination, and livestock movement restrictions with regards to incidence-reduction and likelihood of eradication. Our results suggest countries wishing to control the disease within their borders should focus on comprehensive surveillance and vaccination campaigns as their main policy goals. In summary, vaccination-based policies are more effective than movement restrictions in the endemic context.
Knockout of fatty acid elongase1 homeoalleles in amphidiploid Brassica juncea leads to undetectable erucic acid in seed oil
Nelesh Patra , Guy C. Barker , Mrinal K. Maiti
Indian mustard (Brassica juncea L.) seed oil offers valuable dietary benefits due to a balanced ratio of human essential fatty acids, the traditional high oil-yielding varieties contain an elevated level of erucic acid (EA, C22:1) associated with adverse health effects. Therefore, developing low erucic acid (LEA) mustard cultivars is crucial for broader utilization and consumer safety. In this study, CRISPR/Cas9 genome editing tool was employed to disrupt the fatty acid elongase1 (FAE1) gene that encodes a key enzyme in EA biosynthesis in two high erucic acid (HEA) B. juncea cultivars, PCR7 (∼39% EA) and JD6 (∼45% EA). Our findings underscore the effectiveness of CRISPR/Cas9 technology for editing B. juncea genome, developing plant lines producing LEA seed oil with improved nutritional quality and broadening the utility of this important oilseed crop for food and non-food applications.
Phylodynamic analysis of a prolonged meningococcal epidemic reveals multiple introductions and pre-epidemic expansion
Zuyu Yang, Heather Davies, Jane Clapham, Liza Lopez, Holly B Bratcher, Audrey Tong, Xavier Didelot, Martin C.J. Maiden, Philip E. Carter, Xiaoyun Ren
Neisseria meningitidis is the causative agent of invasive meningococcal disease (IMD), a form of bacterial meningitis and septicaemia, leading to isolated cases, outbreaks, and epidemics worldwide. Between 1991 and 2008, Aotearoa/New Zealand (NZ) experienced a prolonged hyperendemic group B IMD outbreak caused by the NZMenB epidemic strain. To understand NZMenB origin and initiation we used phylodynamic tools to analyse approximately 97 % of all NZMenB isolates submitted to the NZ Meningococcal Reference Laboratory from 1990 to 2019.. Our evidence from molecular dating and clonal expansion analysis suggests that NZMenB was circulating and had expanded before the epidemic. Comparison with international data showed multiple importations and re-introductions of NZMenB into NZ, while not suggesting close relationships with international variants. We propose the NZMenB epidemic may have been triggered by increasing societal inequality and household crowding resulting from government policies at the time.
Piperideine-6-carboxylic acid regulates vitamin B6 homeostasis and modulates systemic immunity in plants
Huazhen Liu, Lakshminarayan M. Iyer, Paul Norris, Ruiying Liu, Keshun Yu, Murray Grant, L. Aravind, Aardra Kachroo & Pradeep Kachroo
Dietary consumption of lysine in humans leads to the biosynthesis of Δ1-piperideine-6-carboxylic acid (P6C), with elevated levels linked to the neurological disorder epilepsy. Here we demonstrate that P6C biosynthesis is also a critical component of lysine catabolism in Arabidopsis thaliana. P6C regulates vitamin B6 homeostasis, and increased P6C levels deplete B6 vitamers, resulting in compromised plant immunity. We further establish a key role for pyridoxal and pyridoxal-5-phosphate biosynthesis in plant immunity. Our analysis indicates that P6C metabolism probably evolved through combining select lysine and proline metabolic enzymes horizontally acquired from diverse bacterial sources at different points during evolution. More generally, certain enzymes from the lysine and proline metabolic pathways were probably recruited in evolution as potential guardians of B6 vitamers and for semialdehyde detoxification.