Die-off of plant pathogenic bacteria in tile drainage and anoxic water from a managed aquifer recharge site

Abstract

Managed aquifer recharge (MAR) can provide irrigation water and overcome water scarcity in agriculture. Removal of potentially present plant pathogens during MAR is essential to prevent crop diseases. We studied the die-off of three plant pathogenic bacteria in water microcosms with natural or filtered tile drainage water (TDW) at 10 and 25°C and with natural anoxic aquifer water (AW) at 10°C from a MAR site. These bacteria were: Ralstonia solanacearum (bacterial wilt), and the soft rot Pectobacteriaceae (SRP) Dickeya solani and Pectobacterium carotovorum sp. carotovorum (soft rot, blackleg). They are present in surface waters and cause destructive crop diseases worldwide which have been linked to contaminated irrigation water. Nevertheless, little is known about the survival of the SRP in aqueous environments and no study has investigated the persistence of R. solanacearum under natural anoxic conditions. We found that all bacteria were undetectable in 0.1 mL samples within 19 days under oxic conditions in natural TDW at 10°C, using viable cell counting, corresponding to 3-log10 reduction by die-off. The SRP were no longer detected within 6 days at 25°C, whereas R. solanacearum was detectable for 25 days. Whereas in anoxic natural aquifer water at 10°C, the bacterial concentrations declined slower and the detection limit was reached within 56 days. Finally, we modelled the inactivation curves with a modified Weibull model that can simulate different curve shapes such as shoulder phenomena in the beginning and long tails reflecting persistent bacterial populations. The non-linear model was shown to be a reliable tool to predict the die-off of the analysed plant pathogenic bacteria, suggesting its further application to other pathogenic microorganisms in the context of microbial risk assessment.

The 21st century water quality challenges for managed aquifer recharge: towards a risk-based regulatory approach

“…1 ). Such complex and uncertain risks can be dealt with through decades of experience in water quality improvement and management in MAR, furthered by targeted research—for example, a study that evaluates the die-off of plant pathogenic bacteria when stormwater is used to recharge a brackish anoxic aquifer in the Netherlands can enhance confidence in the recovered water’s intended use for irrigation (Eisfeld et al 2021 ). Knowledge of biodegradation of trace organic chemicals or contaminants of concern has been advanced through the application of genomic markers to infer the prevailing trophic state of microbial communities in a MAR scheme, and subsequently, predict favorable conditions for removal (Filter et al 2021 ).…”

Dose-response relationship of Ralstonia solanacearum and potato in greenhouse and in vitro experiments

“…The die-off of R. solanacearum populations in noncultivated soil was modelled with a non-linear Weibull + tail model as described in Eisfeld et al (2021).…”

A review on risk assessment in managed aquifer recharge

“…Moreover, problems may arise from the malfunction or failure of technical equipment or infrastructure (e.g., Bartak et al, 2015; Bugan et al, 2016; Ji & Lee, 2016a; Juntunen et al, 2017; Pindoria‐Nandha, 2016; Rodríguez‐Escales et al, 2018; Swierc et al, 2005) and a lack of (trained) operating staff or technical knowledge (Assmuth et al, 2016; Dillon, Fernández Escalante, et al, 2020; Rodríguez‐Escales et al, 2018; Swierc et al, 2005). If water derived from MAR is used for irrigation and this water has high salinity or is contaminated, plant health can be affected, leading to reduced agricultural yields (e.g., Eisfeld et al, 2021; ISO, 2015). When water is stored before final use, microbial regrowth, disinfection byproducts, or algae growth can occur due to malfunction or design flaws of the infrastructure (Bouwer et al, 2008; Bugan et al, 2016; Lee & Ji, 2016; Pavelic et al, 2005).…”