Botryosphaeriaceae associated with Acacia heterophylla (La Réunion) and Acacia koa (Hawaii)

Acacia koa and A. heterophylla are commonly occurring native trees on the Hawaiian Islands and La Réunion, respectively. A recent phylogenetic study suggested that A. heterophylla renders A. koa paraphyletic, and that the former likely arose from the Hawaiian Islands around 1.4 million years ago. An intriguing question is whether their microbiota is similar, although they occur naturally in two very distant geographical locations. In this study, we compared the fungi in the Botryosphaeriaceae isolated from natural populations of A. koa and A. heterophylla. These fungi were chosen because they commonly occur on woody plants and some are important pathogens. They are also known to have been moved globally on asymptomatic plant materials. Isolates were identified based on comparisons of DNA sequence data for the rDNA-ITS, TEF1-α and β-tubulin loci. Ten Botryosphaeriaceae species were identified, of which four species were specific to A. koa from the Hawaiian Islands and five to A. heterophylla in La Réunion. Only one species, Neofusicoccum parvum, which is known to have a wide global distribution, was common to both hosts. The overall results of this study suggest that although A. koa and A. heterophylla share a recent evolutionary history, they have established independent microbiota, at least in terms of the Botryosphaeriaceae.Supplementary material: Multimedia component 2. Figure S1. Maximum Likelihood (ML) tree drawn from ITS sequence data. Bootstrap values above 75 % are given at the nodes. The tree was rooted to Phyllosticta citricarpa (CBS 102374). Sequences produced in this study are indicated in colour. Figure S2. Maximum Likelihood (ML) tree drawn from TEF1-α sequence data. Bootstrap values above 75 % are given at the nodes. The tree was rooted to Phyllosticta citricarpa (CBS 102374). Sequences produced in this study are indicated in colour. Figure S3. Maximum Likelihood (ML) tree drawn from β-tubulin sequence data. Bootstrap values above 75 % are given at the nodes. The tree was rooted to Phyllosticta citricarpa (CBS 102374). Sequences produced in this study are indicated in colour.Members of the Tree Protection Cooperative Programme (TPCP), the DST/NRF Centre of Excellence for Invasion Biology, Centre of Excellence in Tree Health Biotechnology (CTHB) and the University of Pretoria, South Africa.http://www.elsevier.com/locate/funbio2020-11-01hj2019BiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant Patholog