Honey bee‐assisted surveillance for early plant virus detection

Abstract

Incursions of plant viral pathogens are a primary concern for horticulture as they can significantly impact crop yields and require expensive management. Early detection of plant viruses is critical for effective plant biosecurity because it enables growers to respond quickly and limit their spread. However, current surveillance methods relying on enzyme‐linked immunosorbent assay and PCR testing of plant material can only operate at a limited scale. It quickly becomes unfeasible to test a large number of samples for area‐wide surveillance of multiple viruses and ineffective in novel virus discovery. Advances in high‐throughput sequencing (HTS) platforms have greatly improved our surveillance capability and its value demonstrated for screening plant material for viral pathogens. However, while HTS can improve detection, it does not necessarily address the issue of sampling effort needed to achieve early detection. The solution is to couple HTS with a method of constant surveillance and sampling from potentially infected plants. We propose that when managed honey bee (Apis mellifera) hives are brought to flowering crops to deliver essential pollination services, they can also provide valuable surveillance by effectively “sampling” entire crops as they collect pollen and nectar. Combining the ability of honey bees to create a representative sample from a large number of plants with the sensitivity of HTS offers a powerful system for early detection of plant viruses. We describe a novel approach to plant biosecurity where HTS virus detection in honey bees was found to provide earlier detection of plant virus incursions in Australia than current surveillance programmes. In 2013–2014, a national virus survey of honey bees was conducted, which used HTS screening of pooled honey bee samples across Australia. This HTS data simultaneously identified multiple plant viruses in these samples and showed the presence of cucumber green mottle mosaic virus in several states of Australia before its subsequent detection from diseased plant material.