Investigating the Longevity and Infectivity of Cucumber green mottle mosaic virus in Soils of the Northern Territory, Australia

Abstract

Cucumber green mottle mosaic virus (CGMMV) is a Tobamovirus of economic importance affecting cucurbit crops and Asian cucurbit vegetables. CGMMV was detected in the Northern Territory (NT) in September 2014, the first record for Australia, with 26 properties confirmed as of May 2016. Research was undertaken to determine virus longevity in soils in the NT and investigate the use of disinfectants to remove viable CGMMV from the soil. An in-field trial at 12 months post-quarantine at four properties, and bioassays from collected soils indicate that CGMMV remained viable in at least two of the properties 12 months after plant hosts were removed from the ground. The infectivity of CGMMV from soil was also investigated in two trials with 140 watermelon seeds and 70 watermelon plants sown into CGMMV infested soils with or without the application of the disinfectants VirkonTM (2%) and Bleach (1%). Watermelons grown in soil, not treated with the VirkonTM or Bleach, showed CGMMV infection rates of 4% and 2.5% respectively. When VirkonTM or Bleach was applied, no positive CGMMV detections were observed in the watermelons. This research highlights the importance of proper management of infested properties and the need for on-farm biosecurity to manage CGMMV.

Genome Characterisation of the CGMMV Virus Population in Australia—Informing Plant Biosecurity Policy

“…Establishment of CGMMV after introduction can lead to further spread by farm machinery, grafting tools, seed trays, clothes, shoes and hands [ 8 , 59 , 60 ]. Dispersal of CGMMV can continue with subsequent planting in soils contaminated with virus-positive plant debris [ 59 , 61 ] and irrigation systems, such as drip and flow irrigation [ 59 ]. Movement of virus-positive fresh produce and associated contaminated surfaces can introduce inoculum into post-harvest settings and, in turn, back into production areas.…”

Ability of Non-Hosts and Cucurbitaceous Weeds to Transmit Cucumber Green Mottle Mosaic Virus

“…Conventional RT-PCRs were performed using a Veriti Thermal Cycler (ThermoFisher Scientific, Waltham, MA, USA), utilising Superscript III One Step with Platinum Taq (ThermoFisher Scientific, Waltham, MA, USA), following the manufacturers guidelines. The conditions used in this study can be found in a recent publication from the author [ 14 ], and the primers used were: Coat Protein (CP) (496 bp) [ 15 ] Forward primer, 5′-GATGGCTTACAATCCGATCAC-3′ and Reverse primer, 5′-CCCTCGAAACTAAGCTTTCG-3′; Movement Protein (MP) (809 bp) [ 16 ] Forward primer, 5′-TAAGTTTGCTAGGTGTGATC-3′ and Reverse primer, 5′-ACATAGATGTCTCTAAGTAAG-3′; CGMMV RNA helicase subunit (1053 bp) [ 17 ] Forward primer, 5′-ATGGCAAACATTAATGAACAAAT-3′ and Reverse primer, 5′-AACCACACAGAAAACGTGGC-3′.…”

“…RT-qPCR was performed on a Rotor-Gene 6000 (Qiagen, Hilden, Germany) with SensiFAST TM SYBR ® No-ROX One-Step Kit (Bioline Pty Ltd., Taunton, MA, USA) following the manufacturer’s conditions. The conditions used in this study can be found in a recent publication from the author [ 14 ]; the primers used were: Forward primer, 5′-GTGGTTTCTGGTGTATGGAACGTA-3′, Reverse primer, 5′-CGGGAGCTGAAAATTTGCATATAGT-3′, and probe (RZ_CGMMVmp-03), 5′-[FAM]CACCCCTACAGGATTC[NFQMGB]-3′ [ 18 ].…”

A study on tomato brown rugose fruit virus longevity in soil and virion susceptibility to various pH treatments contributes to optimization of a soil disinfection protocol

“…TMV remained infective in buried root debris for at least 13 months (Broadbent et al, 1965; Broadbent, 1976). The cucurbit-infecting tobamovirus cucumber green mottle mosaic virus (CGMMV) remained infective in soil for 17 months after the removal of infected watermelon plants (Lovelock et al, 2022). In addition, overwintered soil contaminated with CGMMV-infected plant debris remained infective in bottle gourd propagation (Li et al, 2016).…”