ANALYSIS OF MICROBIAL COMMUNITIES OF MACROCYSTIS PYRIFERA GAMETOPHYTES: CHARACTERIZATION OF METAGENOME-ASSEMBLED GENOMES AND ISOLATED BACTERIA

Macrocystis pyrifera (giant kelp) is a brown macroalga that is found in coastal coldwater marine environments and is known for its accelerated growth. It plays a significant role ecologically (as a keystone species) and economically (as an aquaculture product). Seaweed-associated bacteria play a crucial role in the functional biology of their host. Despite the significance of microbial and kelp interactions, the microbiota of kelp remains understudied. We analyzed the 5 most abundant genera present in a set of 178 gametophytes (haploid life stage) sampled from 4 different sampling sites Channel Islands (Cl), Leo Carrillo (LC), Camp Padleton (CP), Arroyo Quemando (AQ). We compared bacterial MAGs through pangenomes and phylogenetic analysis to determine the dynamic between bacterial phylogeny and the host genotype in consideration of their respective geographical location. Alongside comparative genomics, we created a collection of bacterial isolates that are representative of their host and sample location. We determined if cultured bacteria were similar to those identified in the MAGs. This work expands our basic understanding of these ecological interactions and could support the argument for the presence of a core microbial community during the gametophyte life stage and perhaps suggest kelp selectively of specific bacteria, as well as enabling further scientific investigation. Analysis of the core genes and flexible genes illustrated differences in genes in correlation to the sample sites. These gene differences included contrasts in vitamin B biosynthesis.

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Primary Presenter: Pascal Cabuzel, University of Southern California (cabuzel@usc.edu)

Authors:

Eesha Rangani, University of Southern California  (rangani@usc.edu)

Danny Osorio, University of Southern California  (daosorio@usc.edu)

Thomas Day, University of Southern California  (daythoma@usc.edu)

Julia Schwartzman, University of Southern California  (Julias21@usc.edu)