Development of a lateral flow device for in‐field detection and evaluation of PCR‐based diagnostic methods for Xanthomonas campestris pv. musacearum, the causal agent of banana xanthomonas wilt

Abstract

Xanthomonas campestris pv. musacearum (Xcm) is the causal agent of banana xanthomonas wilt, a major threat to banana production in eastern and central Africa. The pathogen is present in very high levels within infected plants and can be transmitted by a broad range of mechanisms; therefore early specific detection is vital for effective disease management. In this study, a polyclonal antibody (pAb) was developed and deployed in a lateral flow device (LFD) format to allow rapid in-field detection of Xcm. Published Xcm PCR assays were also independently assessed: only two assays gave specific amplification of Xcm, whilst others cross-reacted with non-target Xanthomonas species. Pure cultures of Xcm were used to immunize a rabbit, the IgG antibodies purified from the serum and the resulting polyclonal antibodies tested using ELISA and LFD. Testing against a wide range of bacterial species showed the pAb detected all strains of Xcm, representing isolates from seven countries and the known genetic diversity of Xcm. The pAb also detected the closely related Xanthomonas axonopodis pv. vasculorum (Xav), primarily a sugarcane pathogen. Detection was successful in both naturally and experimentally infected banana plants, and the LFD limit of detection was 10 5 cells mL À1 . Whilst the pAb is not fully specific for Xcm, Xav has never been found in banana. Therefore the LFD can be used as a first-line screening tool to detect Xcm in the field. Testing by LFD requires no equipment, can be performed by non-scientists and is cost-effective. Therefore this LFD provides a vital tool to aid in the management and control of Xcm.

Xanthomonas campestris pv. musacearum: a major constraint to banana, plantain and enset production in central and east Africa over the past decade

“…Hodgetts et al . () developed a lateral flow device (LFD) using pAbs to detect Xcm in infected banana plants. This tool can be used as a preliminary Xcm screening method.…”

Rapid, specific, simple, in-field detection ofXanthomonas campestrispathovarmusacearumby loop-mediated isothermal amplification

“…() produced specific amplification of all Xcm isolates tested and did not detect any other xanthomonads tested (Hodgetts et al . ). In this study, the GspD gene was used as a target to design and validate a LAMP assay to provide specific, rapid amplification of Xcm using a platform suited for resource poor laboratories and/or in‐field detection operated by personnel with basic training.…”

A Probabilistic Risk Assessment of the National Economic Impacts of Regulatory Drought Management on Irrigated Agriculture

“…Governmental actors will need to effectively communicate with water users in order to enhance coordination and drought response (Urquijo & De Stefano, 2016). The challenge of balancing the multiple competing demands for water (including the environment) within a changing climate, while supporting food security and rural livelihoods, will require a multiscale adaptive drought management framework (Holman & Trawick, 2011) that brings together regulators, collective action, and farmers' response (Rey et al, 2017), reconciles their competing demands (Knox et al, 2018), and learns from international drought management experiences (e.g., Iglesias et al, 2018).…”