title: Genetic basis of priority effects: insights from nectar yeast.
abstract: Priority effects, in which the order of species arrival dictates community assembly, can have a major influence on species diversity, but the genetic basis of priority effects remains unknown. Here, we suggest that nitrogen scavenging genes previously considered responsible for starvation avoidance may drive priority effects by causing rapid resource depletion. Using single-molecule sequencing, we de novo assembled the genome of the nectar-colonizing yeast, Metschnikowia reukaufii, across eight scaffolds and complete mitochondrion, with gap-free coverage over gene spaces. We found a high rate of tandem gene duplication in this genome, enriched for nitrogen metabolism and transport. Both high-capacity amino acid importers, GAP1 and PUT4, present as tandem gene arrays, were highly expressed in synthetic nectar and regulated by the availability and quality of amino acids. In experiments with competitive nectar yeast, Candida rancensis, amino acid addition alleviated suppression of C. rancensis by early arrival of M. reukaufii, corroborating that amino acid scavenging may contribute to priority effects. Because niche pre-emption via rapid resource depletion may underlie priority effects in a broad range of microbial, plant and animal communities, nutrient scavenging genes like the ones we considered here may be broadly relevant to understanding priority effects.
authors.affiliation: Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA mdhami@stanford.edu.
authors.forename: Manpreet K
authors.identifier: 0000-0002-8956-0674
authors.initials: MK
authors.lastname: Dhami
authors.affiliation: Department of Plant Biology, Carnegie Institution for Science, 260 Panama Street, Stanford, CA 94305, USA.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hartwig
authors.affiliation: Department of Biology, Stanford University, 371 Serra Mall, Stanford, CA 94305, USA fukamit@stanford.edu.
authors.forename: Tadashi
authors.identifier: 0000-0001-5654-4785
authors.initials: T
authors.lastname: Fukami
mesh_terms: D020440:Gene Duplication; D016681:Genome, Fungal; D055163:Metschnikowia / Q000235:genetics*; D057048:Plant Nectar; D010944:Plants / Q000382:microbiology*
chemical_list: D057048:Plant Nectar
keywords: community assembly; competition; resource pre-emption; species interaction; tandem gene duplication