@article{lassiter_russ_nusbaum_zeng_saville_olarte_carbone_hu_seguin-orlando_samaniego_et al._2015, title={Mitochondrial genome sequences reveal evolutionary relationships of the Phytophthora 1c clade species}, volume={61}, ISSN={0172-8083 1432-0983}, url={http://dx.doi.org/10.1007/s00294-015-0480-3}, DOI={10.1007/s00294-015-0480-3}, abstractNote={Phytophthora infestans is one of the most destructive plant pathogens of potato and tomato globally. The pathogen is closely related to four other Phytophthora species in the 1c clade including P. phaseoli, P. ipomoeae, P. mirabilis and P. andina that are important pathogens of other wild and domesticated hosts. P. andina is an interspecific hybrid between P. infestans and an unknown Phytophthora species. We have sequenced mitochondrial genomes of the sister species of P. infestans and examined the evolutionary relationships within the clade. Phylogenetic analysis indicates that the P. phaseoli mitochondrial lineage is basal within the clade. P. mirabilis and P. ipomoeae are sister lineages and share a common ancestor with the Ic mitochondrial lineage of P. andina. These lineages in turn are sister to the P. infestans and P. andina Ia mitochondrial lineages. The P. andina Ic lineage diverged much earlier than the P. andina Ia mitochondrial lineage and P. infestans. The presence of two mitochondrial lineages in P. andina supports the hybrid nature of this species. The ancestral state of the P. andina Ic lineage in the tree and its occurrence only in the Andean regions of Ecuador, Colombia and Peru suggests that the origin of this species hybrid in nature may occur there.}, number={4}, journal={Current Genetics}, publisher={Springer Science and Business Media LLC}, author={Lassiter, Erica S. and Russ, Carsten and Nusbaum, Chad and Zeng, Qiandong and Saville, Amanda C. and Olarte, Rodrigo A. and Carbone, Ignazio and Hu, Chia-Hui and Seguin-Orlando, Andaine and Samaniego, Jose A. and et al.}, year={2015}, month={Mar}, pages={567–577} }
 @article{olarte_horn_singh_carbone_2015, title={Sexual recombination in Aspergillus tubingensis}, volume={107}, ISSN={["1557-2536"]}, DOI={10.3852/14-233}, abstractNote={Aspergillus tubingensis from section Nigri (black Aspergilli) is closely related to A. niger and is used extensively in the industrial production of enzymes and organic acids. We recently discovered sexual reproduction in A. tubingensis, and in this study we demonstrate that the progeny are products of meiosis. Progeny were obtained from six crosses involving five MAT1-1 strains and two MAT1-2 strains. We examined three loci, including mating type (MAT), RNA polymerase II (RPB2) and β-tubulin (BT2), and found that 84% (58/69) of progeny were recombinants. Recombination associated with sexual reproduction in A. tubingensis provides a new option for the genetic improvement of industrial strains for enzyme and organic acid production.}, number={2}, journal={MYCOLOGIA}, author={Olarte, Rodrigo A. and Horn, Bruce W. and Singh, Rakhi and Carbone, Ignazio}, year={2015}, pages={307–312} }
 @article{horn_sorensen_lamb_sobolev_olarte_worthington_carbone_2014, title={Sexual Reproduction in Aspergillus flavus Sclerotia Naturally Produced in Corn}, volume={104}, ISSN={["1943-7684"]}, DOI={10.1094/phyto-05-13-0129-r}, abstractNote={ Aspergillus flavus is the major producer of carcinogenic aflatoxins worldwide in crops. Populations of A. flavus are characterized by high genetic variation and the source of this variation is likely sexual reproduction. The fungus is heterothallic and laboratory crosses produce ascospore-bearing ascocarps embedded within sclerotia. However, the capacity for sexual reproduction in sclerotia naturally formed in crops has not been examined. Corn was grown for 3 years under different levels of drought stress at Shellman, GA, and sclerotia were recovered from 146 ears (0.6% of ears). Sclerotia of A. flavus L strain were dominant in 2010 and 2011 and sclerotia of A. flavus S strain were dominant in 2012. The incidence of S strain sclerotia in corn ears increased with decreasing water availability. Ascocarps were not detected in sclerotia at harvest but incubation of sclerotia on the surface of nonsterile soil in the laboratory resulted in the formation of viable ascospores in A. flavus L and S strains and in homothallic A. alliaceus. Ascospores were produced by section Flavi species in 6.1% of the 6,022 sclerotia (18 of 84 ears) in 2010, 0.1% of the 2,846 sclerotia (3 of 36 ears) in 2011, and 0.5% of the 3,106 sclerotia (5 of 26 ears) in 2012. For sexual reproduction to occur under field conditions, sclerotia may require an additional incubation period on soil following dispersal at crop harvest. }, number={1}, journal={PHYTOPATHOLOGY}, author={Horn, Bruce W. and Sorensen, Ronald B. and Lamb, Marshall C. and Sobolev, Victor S. and Olarte, Rodrigo A. and Worthington, Carolyn J. and Carbone, Ignazio}, year={2014}, month={Jan}, pages={75–85} }
 @article{horn_olarte_peterson_carbone_2013, title={Sexual reproduction in Aspergillus tubingensis from section Nigri}, volume={105}, ISSN={0027-5514 1557-2536}, url={http://dx.doi.org/10.3852/13-101}, DOI={10.3852/13-101}, abstractNote={A sclerotium-forming member of Aspergillus section Nigri was sampled from a population in a single field in North Carolina, USA, and identified as A. tubingensis based on genealogical concordance analysis. Aspergillus tubingensis was shown to be heterothallic, with individual strains containing either a MAT1-1 or MAT1-2 mating-type gene. Strains of opposite mating type were crossed on mixed cereal agar and incubated for 5–6 months. Stromata typically formed 1–2 indehiscent ascocarps containing asci and ascospores within the pseudo-parenchymatous matrix in a manner similar to the Petromyces sexual stage from section Flavi, which is closely related to section Nigri. Ascospores of A. tubingensis differed from those of section Flavi species in the reticulate ornamentation of ascospores and the presence of two crests that form an equatorial furrow. Sexual reproduction in A. tubingensis may be useful for enhancing enzyme and organic acid production through recombination-mediated genetic engineering of industrial strains.}, number={5}, journal={Mycologia}, publisher={Informa UK Limited}, author={Horn, Bruce W. and Olarte, Rodrigo A. and Peterson, Stephen W. and Carbone, Ignazio}, year={2013}, month={Sep}, pages={1153–1163} }
 @article{olarte_horn_dorner_monacell_singh_stone_carbone_2012, title={Effect of sexual recombination on population diversity in aflatoxin production by Aspergillus flavus and evidence for cryptic heterokaryosis}, volume={21}, ISSN={["1365-294X"]}, DOI={10.1111/j.1365-294x.2011.05398.x}, abstractNote={AbstractAspergillus flavus is the major producer of carcinogenic aflatoxins (AFs) in crops worldwide. Natural populations of A. flavus show tremendous variation in AF production, some of which can be attributed to environmental conditions, differential regulation of the AF biosynthetic pathway and deletions or loss‐of‐function mutations in the AF gene cluster. Understanding the evolutionary processes that generate genetic diversity in A. flavus may also explain quantitative differences in aflatoxigenicity. Several population studies using multilocus genealogical approaches provide indirect evidence of recombination in the genome and specifically in the AF gene cluster. More recently, A. flavus has been shown to be functionally heterothallic and capable of sexual reproduction in laboratory crosses. In the present study, we characterize the progeny from nine A. flavus crosses using toxin phenotype assays, DNA sequence‐based markers and array comparative genome hybridization. We show high AF heritability linked to genetic variation in the AF gene cluster, as well as recombination through the independent assortment of chromosomes and through crossing over within the AF cluster that coincides with inferred recombination blocks and hotspots in natural populations. Moreover, the vertical transmission of cryptic alleles indicates that while an A. flavus deletion strain is predominantly homokaryotic, it may harbour AF cluster genes at a low copy number. Results from experimental matings indicate that sexual recombination is driving genetic and functional hyperdiversity in A. flavus. The results of this study have significant implications for managing AF contamination of crops and for improving biocontrol strategies using nonaflatoxigenic strains of A. flavus.}, number={6}, journal={MOLECULAR ECOLOGY}, author={Olarte, Rodrigo A. and Horn, Bruce W. and Dorner, Joe W. and Monacell, James T. and Singh, Rakhi and Stone, Eric A. and Carbone, Ignazio}, year={2012}, month={Mar}, pages={1453–1476} }