Floral nectar is a harsh environment that hosts a complex community of microbes. Floricolous yeast, Metschnikowia reukaufii, is a dominant species in this community, competing with other fungi and bacteria. Specifically, this species exerts a strong priority effect, excluding other microbes and deterministically influencing community structure. We sequenced the genome of M. reukaufii and identified the genetic mechanisms by which it specialises in nectar. We found a high rate of tandem gene duplication in the genome, with majority of duplicated genes involved in nitrogen metabolism and transport. The two high-capacity amino acid transport genes, GAP1 and PUT4, involved in amino acid scavenging when nitrogen is scarce, were present in tandem gene arrays. We confirmed that all four copies of GAP1 were expressed in nectar conditions and in fact regulated via the nitrogen catabolite repression pathway, establishing their role in nitrogen scavenging. M. reukaufii is able to efficiently deplete up to 90% of amino acids present in nectar soon after colonisation, limiting potential competition from late-arriving species. These genes, expressed only in nitrogen-limited environment provide an example of adaptation to high carbon, low nitrogen nectar resource, and explain the strong priority effects exhibited by M. reukaufii.