New Zealand Plant Protection 68 (2015): 445
Leptospermum scoparium J.R.Forst. et G.Forst. var. scoparium, or mānuka, is a New Zealand indigenous shrub. This shrub is valued for the essential oil and medicinal honey it produces that have antimicrobial properties. International research has demonstrated that endophytic bacteria can either directly produce, or modify, metabolites in planta. Therefore, bacteria within the mānuka endomicrobiome may also produce antimicrobial compounds. A total of 192 endophytic bacteria were recovered from surface sterilised leaf, stem and root tissue from three different sites. These bacteria were assessed in dual culture assays against the grapevine pathogens Ilyonectria spp. and Neofusicoccum spp. Eleven and three endophytic bacteria showed ability to inhibit I. liriodendri and N. luteum, respectively. These endophytic bacteria produced both diffusible and volatile compounds that inhibited the pathogens. Isolate W4R11 inhibited the growth of Ilyonectria spp. by 41-64% after 7 days incubation. Isolate W1R33 could inhibit the faster growing Neofusicoccum spp. by 20-53% after 3 days incubation. Microscopy showed that diffusible compound produced by isolate I1R21 caused hyphae and spore abnormality of Ilyonectria spp. This study indicated that mānuka can potentially provide a new source of microorganisms for use in sustainable agriculture.
Copyright © 2015 New Zealand Plant Protection Society (Inc.).