Biogeography and population structure of the Neotropical endemic yeast species Metschnikowia lochheadii

Abstract

The genetic structure of populations of the out-crossing haplontic yeast species Metschnikowia lochheadii was investigated. The species is associated with floricolous beetles in Central America and Hawaii. The objective was to determine whether sexual reproduction is prevalent and to what extent the geographic distribution of genotypes can be viewed as historical. The genetic markers examined include the mating type (h (+) or h (-)) and nine polymorphic DNA loci. The data were used to assess population structuring based on F (ST) and linkage disequilibrium and the distribution of alleles using parsimony haplotype networks. In Central America, M. lochheadii is subdivided into sexually active demes between which gene flow is limited. Isolates from five Hawaiian islands had identical haplotypes, confirming that the species has undergone a founder effect concomitant with the recent import of a nitidulid beetle into the archipelago.

Population structure of two beetle-associated yeasts: comparison of a New World asexual and an endemic Nearctic sexual species in the Metschnikowia clade

“…Polymorphic DNA markers Development of polymorphic loci and identification of alleles involved the three-step process detailed by Lachance et al (2008). For screening of polymorphic loci (SWAPP, Burt et al 1994;Gräser et al 1996), three strains of each species were selected on the basis of geographic distribution (Table 1).…”

“…This is one serious difficulty associated with sampling yeasts in their natural habitat. As discussed by Lachance et al (2008), yeast sampling from nature is almost always opportunistic and yeast community definitions suffer from an elusive concept of individual.…”

Geographic delineations of yeast communities and populations associated with vines and wines in New Zealand

“…Technical advances mean the task of describing microbial diversity is accelerating (Hugenholtz et al, 1998;Green et al, 2004), and not unsurprisingly the emerging picture is more complicated than simply accepting or rejecting the classic Bass-Becking idea that dispersal is not limiting for microbes and thus everything is everywhere but the environment selects (Whitaker et al, 2003;Finlay and Fenchel, 2004;Green et al, 2004;Martiny et al, 2006;Nemergut et al, 2011). Most studies to date have focused on bacterial communities (Martiny et al, 2006), but some notable work has been conducted on the biogeography of aquatic protists (Finlay and Fenchel, 2004), soil fungi (Green et al, 2004), and cacti-and flower-associated yeasts (Lachance et al, 2000(Lachance et al, , 2001(Lachance et al, , 2008. However, there are fewer studies that have examined the biogeography of eukaryotic microbes in other niches.…”

The use of parsimony network analysis for the formal delineation of phylogenetic species of yeasts: Candida apicola, Candida azyma, and Candida parazyma sp. nov., cosmopolitan yeasts associated with floricolous insects

“…Greig (2007) pointed out that yeasts are probably not free-living because of their complex interactions with vector insects and suggested that Saccharomyces species probably do have a biogeography, a prediction that seems to have received strong support recently from phylogenomic studies (Liti et al 2009). So far, yeasts found in association with floricolous insects have followed strong biogeographic patterns, be it at the supraspecific (Lachance et al 2001(Lachance et al , 2005 or the infraspecific (Lachance et al 2008;Wardlaw et al 2009) levels. The analysis depicted in Fig.…”