Bacterial metabolites as growth promoting agents to enhance detection of plant diseases

This project will explore and utilise metabolites to boost the growth of key plant pathogens and enhance expression of disease symptoms, especially when pathogens have low titres and are difficult to culture. This will enable more rapid detection of incipient pathogens and their disease symptoms in PEQ, reducing the necessary quarantine period of the plants in the facility.

Imported material may contain low titres or number of plant pathogens such as bacteria, fungi, viruses, and viroids. This is one of the reasons that a long post entry quarantine (PEQ) period is required – often the pathogen needs several growing seasons to replicate for the titre to reach detectable levels.

New genetics and varieties of high value crops are tested for unwanted pathogens before their release within New Zealand. This process is carried out in a high security facility where spaces are limited and can take up to two years before the release. Through this project we propose a new way to reduce the backlog and expedite the quarantine period.

This study is a highly novel approach to enhance pathogen detection. Therefore, this scoping project would be the first step required before it could be used in a biosecurity setting. We will continue to develop this idea and future implementation with the MPI PEQ team by sharing and discussing results throughout the year.

In our previous research work we showed a range of metabolites produced by non-toxic strict anaerobic Clostridium species, being effective at inhibiting the growth of some pathogenic bacteria (https://doi.org/10.1186/s12864-021-08005-2). Recently, we identified that some non-toxic anaerobic bacteria produced a ‘soup’ of metabolites that promoted the growth of some key food spoilage bacteria (data unpublished). Through this scoping project we aim to utilise this concept to- 1) investigate the growth promoting properties of these metabolites on key plant pathogens such as Pseudomonas syringae pv. syringae, Monilinia fructicola, that infect high value crops such as kiwifruit, Prunus and Malus species and 2) assess the impact of these metabolites on expression of disease symptoms on infected plants carrying low titre of the pathogens.

Presently, this research is focused on imported plant germplasm in PEQ, but we acknowledge the implications of potential findings in this study for screening the susceptibility of taonga plants to exotic pathogens.

Contact Project Leader Tanushree Gupt: [email protected]