Phylogenetic Relationships, Pathogenic Traits, and Wood-Destroying Properties of Porodaedalea niemelaei M. Fischer Isolated in the Northern Forest Limit of Larix gmelinii Open Woodlands in the Permafrost Area

The phytopathogenic and wood destroying traits were studied in a basidiomycete fungus, Porodaedalea niemelaei M. Fischer, widespread in Siberian permafrost woodlands of Gmelinii larch, Larix gmelinii (Rupr.) Rupr. Numerous stands of dying out and fallen larch trees with white-rot („corrosion rot“) were found in the study area. Butt rot incidence varied from 63 to 100 % depending on the stand age and raised up to 0.5-1.5 m above root collar on average or up to 9 m maximum. Root rot was also widespread, including larch undergrowth. The biodiversity of xylotrophic fungi was low, with a pronounced dominance of P. niemelaei. The main factors of dying out of L. gmelinii were infection by P. niemelaei promoted by mechanical damage of roots by reindeers during migration and climate anomalies. The cultures isolated from the fruiting bodies were identified as Porodaedalea niemelaei M. Fischer based on the combination of morphological, culture, and molecular genetic methods. Under laboratory conditions, the strains were characterized as psychrotolerant (temperature limit from 6 to 22 °C) and preferred cultural media based mostly on natural and plant substrates. The most active biodegradation occurred on the broadleaf wood substrates causing up to 50 % of the biomass loss accompanied by active decomposing of the lignocellulosic complex and increasing the amount of water-soluble substances. The phylogenetic analysis demonstrated that P. niemelaei is clearly different from other well-studied Porodaedalea species, such as P. chrysoloma, P. pini, and P. cancriformans, and is very close to a group of unclassified fungi isolated in Norway and Finland. The phylogenetic analysis included 43 isolates and was based on four genetic markers – ITS, nLSU, rpb2, and tef1, commonly used in fungal phylogenetic

Heterogeneity of the GFP fitness landscape and data-driven protein design

Studies of protein fitness landscapes reveal biophysical constraints guiding protein evolution and empower prediction of functional proteins. However, generalisation of these findings is limited due to scarceness of systematic data on fitness landscapes of proteins with a defined evolutionary relationship. We characterized the fitness peaks of four orthologous fluorescent proteins with a broad range of sequence divergence. While two of the four studied fitness peaks were sharp, the other two were considerably flatter, being almost entirely free of epistatic interactions. Mutationally robust proteins, characterized by a flat fitness peak, were not optimal templates for machine-learning-driven protein design – instead, predictions were more accurate for fragile proteins with epistatic landscapes. Our work paves insights for practical application of fitness landscape heterogeneity in protein engineering

An experimental assay of the interactions of amino acids from orthologous sequences shaping a complex fitness landscape

Characterizing the fitness landscape, a representation of fitness for a large set of genotypes, is key to understanding how genetic information is interpreted to create functional organisms. Here we determined the evolutionarily-relevant segment of the fitness landscape of His3, a gene coding for an enzyme in the histidine synthesis pathway, focusing on combinations of amino acid states found at orthologous sites of extant species. Just 15% of amino acids found in yeast His3 orthologues were always neutral while the impact on fitness of the remaining 85% depended on the genetic background. Furthermore, at 67% of sites, amino acid replacements were under sign epistasis, having both strongly positive and negative effect in different genetic backgrounds. 46% of sites were under reciprocal sign epistasis. The fitness impact of amino acid replacements was influenced by only a few genetic backgrounds but involved interaction of multiple sites, shaping a rugged fitness landscape in which many of the shortest paths between highly fit genotypes are inaccessible.The work was supported by HHMI International Early Career Scientist Program (55007424), the MINECO (BFU2012-31329, BFU2012-37168, BFU2015-68351-P and BFU2015-68723-P), Spanish Ministry of Economy and Competitiveness Centro de Excelencia Severo Ochoa 2013-2017 grant (SEV-2012-0208), the Unidad de Excelencia María de Maeztu funded by the MINECO (MDM-2014-0370), Secretaria d'Universitats i Recerca del Departament d'Economia i Coneixement de la Generalitat AGAUR program (2014 SGR 0974), the CERCA Programme of the Generalitat de Catalunya, Russian Foundation for Basic Research grant (18-04-01173), the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie programme (665385) and the European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013, ERC grant agreement 335980_EinME and Synergy Grant 609989). KSS was supported by EMBO long-term fellowship (ALTF 107-2016). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Патогенные и дереворазрушающие свойства Porodaedalea niemelaei M. Fischer в редколесьях Larix gmelinii в районах вечной мерзлоты

The phytopathogenic and wood destroying traits were studied in a basidiomycete fungus, Porodaedalea niemelaei M. Fischer, widespread in Siberian permafrost woodlands of Gmelinii larch, Larix gmelinii (Rupr.) Rupr. Numerous stands of dying out and fallen larch trees with white-rot („corrosion rot“) were found in the study area. Butt rot incidence varied from 63 to 100 % depending on the stand age and raised up to 0.5-1.5 m above root collar on average or up to 9 m maximum. Root rot was also widespread, including larch undergrowth. The biodiversity of xylotrophic fungi was low, with a pronounced dominance of P. niemelaei. The main factors of dying out of L. gmelinii were infection by P. niemelaei promoted by mechanical damage of roots by reindeers during migration and climate anomalies. The cultures isolated from the fruiting bodies were identified as Porodaedalea niemelaei M. Fischer based on the combination of morphological, culture, and molecular genetic methods. Under laboratory conditions, the strains were characterized as psychrotolerant (temperature limit from 6 to 22 °C) and preferred cultural media based mostly on natural and plant substrates. The most active biodegradation occurred on the broadleaf wood substrates causing up to 50 % of the biomass loss accompanied by active decomposing of the lignocellulosic complex and increasing the amount of water-soluble substances. The phylogenetic analysis demonstrated that P. niemelaei is clearly different from other well-studied Porodaedalea species, such as P. chrysoloma, P. pini, and P. cancriformans, and is very close to a group of unclassified fungi isolated in Norway and Finland. The phylogenetic analysis included 43 isolates and was based on four genetic markers – ITS, nLSU, rpb2, and tef1, commonly used in fungal phylogeneticsИзучены фитопатогенные и дереворазрушающие свойства базидиального гриба Porodaedalea niemelaei M. Fischer, широко распространённого на территории Сибири в районе вечной мерзлоты в редколесьях Larix gmelinii (Rupr.) Rupr. В районе исследования обнаружены многочисленные куртины усыхающих деревьев и ветровальные лиственницы с наличием коррозионной гнили. Встречаемость напенной гнили варьирует в пределах 63-100 % в зависимости от возраста древостоя; средняя высота подъема 0,5-1,5 м, максимально до 9 м. Корневая гниль распространена повсеместно, включая подрост лиственницы. Биоразнообразие ксилотрофных грибов скудное с выраженным доминированием P. niemelaei. Основным фактором усыхания Larix gmelinii является наличие грибной инфекции, способствующими – механическое повреждение корней и климатические аномалии. Культура гриба, изолированная из плодового тела, по совокупности морфолого-культуральных и молекулярно-генетических методов идентифицирована как Porodaedalea niemelaei M. Fischer. В лабораторных условиях штамм характеризуется как психротолерантный (температурный предел 6-22 °С), предпочитающий питательные среды на основе натуральных растительных компонентов. Биодеструкция растительных субстратов активнее протекает на лиственной древесине – убыль массы до 50 % на фоне активной биодеградации компонентов лигноцеллюлозного комплекса и увеличения количества водорастворимых веществ. Филогенетический анализ выявил значительные отличия P. niemelaei от других хорошо изученных видов Porodaedalea, таких как P. chrysoloma, P. pini и P. cancriformans, и близость к группе неклассифицированных грибов, выделенных в Норвегии и Финляндии. Филогенетический анализ включал 43 изолята и базировался на четырех маркерах (ITS, nLSU, rpb2 и tef1), широко применяемых в филогении грибов. Нуклеотидные последовательности всех маркеров были проверены в недавно полностью секвенированном геноме P. niemelaei, у изолята, использованного в этом исследовании (http://genome.jgi.doe.gov/PornieStandDraft_FD/PornieStandDraft_FD.info.html)