Accelerated aging of plants to shorten post-entry quarantine time whilst optimising pathogen detection

Abstract

The importation of novel plant genetic material into Aotearoa-New Zealand is essential to develop new cultivars, keeping the country at the forefront of innovation that meets consumer demands and changing climate. Importation of Prunus spp. material involves a two-year post-entry quarantine (PEQ) period. Trees must undergo two growth periods where the quarantine level and growth conditions are designed to maximise the detection of unwanted organisms. The speed of plant growth and aging depends on the environment. Applying long day lengths and milder temperatures to the PEQ process may reduce the time required to cycle through two growth cycles. However, it is unclear what impact this would have on our ability to detect pathogens in PEQ. This project compares the current Ministry for Primary Industries (MPI) PEQ environment protocols with our “accelerated aging protocols”, using the climate-controlled Biotron facilities at Lincoln University to determine whether various micro-organisms from differing taxonomic groups can still be detected whilst the phenotype of the trees remains stable. Using cherry trees as a model, phenotypic characteristics have been measured and compared between the two conditions. We have successfully shown that Prunus necrotic ringspot virus can be readily detected in plants grown under the “accelerated aging” conditions. The detection of Pseudomonas syringae pv. syringae (bacterium), and Monilinia fructicola (fungus) under the differing growth conditions still needs further validation. The outputs from this project aim to inform changes to MPI’s PEQ protocols and facilities.