Identification of Bacteria Isolated From Leaves of American Beech, Fagus grandifolia, Infested by the Foliar Nematode, Litylenchus crenatae (Nematoda: Anguinoidea), in New York, USA

Abstract

American beech (Fagus grandifolia) trees exhibiting symptoms of beech leaf disease (BLD) induced by the foliar nematode, Litylenchus crenatae, were found growing in Delmar, New York, USA, in 2019. Foliar symptoms included leaf drop, galling, and darkening associated with leaf curl. Bacterial isolates were cultured from infected leaf tissue and identified to genus by 16S rRNA gene sequencing and MALDI-TOF-MS profiling. In addition to many taxa with putatively environmental roles, strains of the genera Agrobacterium, Curtobacterium, Pantoea, Xanthomonas, as well as Erwinia and Pseudomonas were detected. Strains of the latter two genera have been previously associated with BLD, but isolates have not yet been identified at the species level. Phylogenetic trees generated from sequences of 16S rRNA and housekeeping genes (gyrB, rpoB, and rpoD) combined with MALDI-TOF-MS, showed that the isolates from nematode-infected leaves of American beech belonged to the known plant pathogenic species C. flaccumfaciens, E. billingiae, E. rhapontici, Pa. agglomerans, and X. arboricola. The species affiliation of strains showing close relatedness to A. skierniewicense, A. vaccinii, Pa. alfalfae, Pa. ananatis, Ps. amygdali, Ps. cerasi, and Ps. syringae requires further support. The identities of other bacteria isolated from the same samples are also provided.