An In Vitro Pipeline for Screening and Selection of Citrus-Associated Microbiota with Potential Anti-“ Candidatus Liberibacter asiaticus” Properties

• DOI: 10.1128/aem.02883-19
• Publication Date: 2020-02-19T12:12:07Z
• Authors: Alex Blacutt; Nichole Ginnan; Tyler Dang; Sohrab Bodaghi; Georgios Vidalakis; Paul Ruegger; Beth Peacock; Polrit Viravathana; Flavia Campos Vieira; Christopher Drozd; Barbara Jablonska; James Borneman; Greg McCollum; Jennifer Cordoza; Jeremiah Meloch; Victoria Berry; Lia Lozano Salazar; Katherine N. Maloney; Philippe E. Rolsh...; M. Caroline Roper
• Keywords: 2. Zero hunger; Citrus; 0303 health sciences; natural products; Microbiota; Fungi; bioinoculant; Biological Sciences; Medical microbiology; 15. Life on land; Bacterial Physiological Phenomena; Microbiology; 630; 03 medical and health sciences; Infectious Diseases; Plant Microbiology; Rhizobiaceae; Microbiome; biocontrol; Soil Microbiology; Plant Diseases

Globally, citrus is threatened by huanglongbing (HLB), and the lack of effective control measures is a major concern of farmers, markets, and consumers. There is compelling evidence that plant health is a function of the activities of the plant's associated microbiome. Using Liberibacter crescens , a culturable surrogate for the unculturable HLB-associated bacterium “ Candidatus Liberibacter asiaticus,” we tested the hypothesis that members of the citrus microbiome produce potential anti-“ Ca . Liberibacter asiaticus” natural products with potential anti-“ Ca . Liberibacter asiaticus” activity. A subset of isolates obtained from the microbiome inhibited L. crescens growth in an agar diffusion inhibition assay. Further fractionation experiments linked the inhibitory activity of the fungus Cladosporium cladosporioides to the fungus-produced natural products cladosporols A, C, and D, demonstrating dose-dependent antagonism to L. crescens .