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Gemenet DC, da Silva Pereira G, De Boeck B, Wood JC, Mollinari M, Olukolu BA, Diaz F, Mosquera V, Ssali RT, David M, Kitavi MN, Burgos G, Felde TZ, Ghislain M, Carey E, Swanckaert J, Coin LJM, Fei Z, Hamilton JP, Yada B, Yencho GC, Zeng ZB, Mwanga ROM, Khan A, Gruneberg WJ, Buell CR. Quantitative trait loci and differential gene expression analyses reveal the genetic basis for negatively associated β-carotene and starch content in hexaploid sweetpotato [Ipomoea batatas (L.) Lam.]. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2020; 133:23-36. [PMID: 31595335 PMCID: PMC6952332 DOI: 10.1007/s00122-019-03437-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 09/17/2019] [Indexed: 05/10/2023]
Abstract
KEY MESSAGE β-Carotene content in sweetpotato is associated with the Orange and phytoene synthase genes; due to physical linkage of phytoene synthase with sucrose synthase, β-carotene and starch content are negatively correlated. In populations depending on sweetpotato for food security, starch is an important source of calories, while β-carotene is an important source of provitamin A. The negative association between the two traits contributes to the low nutritional quality of sweetpotato consumed, especially in sub-Saharan Africa. Using a biparental mapping population of 315 F1 progeny generated from a cross between an orange-fleshed and a non-orange-fleshed sweetpotato variety, we identified two major quantitative trait loci (QTL) on linkage group (LG) three (LG3) and twelve (LG12) affecting starch, β-carotene, and their correlated traits, dry matter and flesh color. Analysis of parental haplotypes indicated that these two regions acted pleiotropically to reduce starch content and increase β-carotene in genotypes carrying the orange-fleshed parental haplotype at the LG3 locus. Phytoene synthase and sucrose synthase, the rate-limiting and linked genes located within the QTL on LG3 involved in the carotenoid and starch biosynthesis, respectively, were differentially expressed in Beauregard versus Tanzania storage roots. The Orange gene, the molecular switch for chromoplast biogenesis, located within the QTL on LG12 while not differentially expressed was expressed in developing roots of the parental genotypes. We conclude that these two QTL regions act together in a cis and trans manner to inhibit starch biosynthesis in amyloplasts and enhance chromoplast biogenesis, carotenoid biosynthesis, and accumulation in orange-fleshed sweetpotato. Understanding the genetic basis of this negative association between starch and β-carotene will inform future sweetpotato breeding strategies targeting sweetpotato for food and nutritional security.
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Affiliation(s)
- Dorcus C Gemenet
- International Potato Center, ILRI Campus, Old Naivasha Road, P.O. Box 25171-00603, Nairobi, Kenya.
| | | | - Bert De Boeck
- International Potato Center, Av. La Molina 1895, Lima, Peru
| | - Joshua C Wood
- Michigan State University, East Lansing, MI, 48824, USA
| | | | - Bode A Olukolu
- North Carolina State University, Raleigh, NC, 27695, USA
- University of Tennessee, Knoxville, TN, 37996, USA
| | - Federico Diaz
- International Potato Center, Av. La Molina 1895, Lima, Peru
| | | | | | - Maria David
- International Potato Center, Av. La Molina 1895, Lima, Peru
| | - Mercy N Kitavi
- International Potato Center, ILRI Campus, Old Naivasha Road, P.O. Box 25171-00603, Nairobi, Kenya
| | | | | | - Marc Ghislain
- International Potato Center, ILRI Campus, Old Naivasha Road, P.O. Box 25171-00603, Nairobi, Kenya
| | | | | | - Lachlan J M Coin
- University of Queensland, St. Lucia, Brisbane, QLD, 4072, Australia
| | - Zhangjun Fei
- Boyce Thompson Institute, Cornell University, Ithaca, NY, 14853, USA
| | | | - Benard Yada
- National Crops Resources Research Institute (NaCCRI), Namulonge, P.O. Box 7084, Kampala, Uganda
| | - G Craig Yencho
- North Carolina State University, Raleigh, NC, 27695, USA
| | - Zhao-Bang Zeng
- North Carolina State University, Raleigh, NC, 27695, USA
| | | | - Awais Khan
- International Potato Center, Av. La Molina 1895, Lima, Peru
- Plant Pathology and Plant-Microbe Biology Section, Cornell University, Geneva, NY, 14456, USA
| | | | - C Robin Buell
- Michigan State University, East Lansing, MI, 48824, USA
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102
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Unpredictable Effects of the Genetic Background of Transgenic Lines in Physiological Quantitative Traits. G3-GENES GENOMES GENETICS 2019; 9:3877-3890. [PMID: 31540975 PMCID: PMC6829147 DOI: 10.1534/g3.119.400715] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Physiology, fitness and disease phenotypes are complex traits exhibiting continuous variation in natural populations. To understand complex trait gene functions transgenic lines of undefined genetic background are often combined to assess quantitative phenotypes ignoring the impact of genetic polymorphisms. Here, we used inbred wild-type strains of the Drosophila Genetics Reference Panel to assess the phenotypic variation of six physiological and fitness traits, namely, female fecundity, survival and intestinal mitosis upon oral infection, defecation rate and fecal pH upon oral infection, and terminal tracheal cell branching in hypoxia. We found continuous variation in the approximately 150 strains tested for each trait, with extreme values differing by more than four standard deviations for all traits. In addition, we assessed the effects of commonly used Drosophila UAS-RNAi transgenic strains and their backcrossed isogenized counterparts, in the same traits plus baseline intestinal mitosis and tracheal branching in normoxia, in heterozygous conditions, when only half of the genetic background was different among strains. We tested 20 non-isogenic strains (10 KK and 10 GD) from the Vienna Drosophila Resource Center and their isogenized counterparts without Gal4 induction. Survival upon infection and female fecundity exhibited differences in 50% and 40% of the tested isogenic vs. non-isogenic pairs, respectively, whereas all other traits were affected in only 10–25% of the cases. When 11 isogenic and their corresponding non-isogenic UAS-RNAi lines were expressed ubiquitously with Gal4, 4 isogenic vs. non-isogenic pairs exhibited differences in survival to infection. Furthermore, when a single UAS-RNAi line was crossed with the same Gal4 transgene inserted in different genetic backgrounds, the quantitative variations observed were unpredictable on the basis of pure line performance. Thus, irrespective of the trait of interest, the genetic background of commonly used transgenic strains needs to be considered carefully during experimentation.
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103
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Hybridization increases population variation during adaptive radiation. Proc Natl Acad Sci U S A 2019; 116:23216-23224. [PMID: 31659024 DOI: 10.1073/pnas.1913534116] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Adaptive radiations are prominent components of the world's biodiversity. They comprise many species derived from one or a small number of ancestral species in a geologically short time that have diversified into a variety of ecological niches. Several authors have proposed that introgressive hybridization has been important in the generation of new morphologies and even new species, but how that happens throughout evolutionary history is not known. Interspecific gene exchange is expected to have greatest impact on variation if it occurs after species have diverged genetically and phenotypically but before genetic incompatibilities arise. We use a dated phylogeny to infer that populations of Darwin's finches in the Galápagos became more variable in morphological traits through time, consistent with the hybridization hypothesis, and then declined in variation after reaching a peak. Some species vary substantially more than others. Phylogenetic inferences of hybridization are supported by field observations of contemporary hybridization. Morphological effects of hybridization have been investigated on the small island of Daphne Major by documenting changes in hybridizing populations of Geospiza fortis and Geospiza scandens over a 30-y period. G. scandens showed more evidence of admixture than G. fortis Beaks of G. scandens became progressively blunter, and while variation in length increased, variation in depth decreased. These changes imply independent effects of introgression on 2, genetically correlated, beak dimensions. Our study shows how introgressive hybridization can alter ecologically important traits, increase morphological variation as a radiation proceeds, and enhance the potential for future evolution in changing environments.
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104
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García G, Ríos N, Gutiérrez V, Serra S, Loureiro M. Transcriptome-Based SNP Discovery and Validation in the Hybrid Zone of the Neotropical Annual Fish Genus Austrolebias. Genes (Basel) 2019; 10:genes10100789. [PMID: 31614537 PMCID: PMC6826752 DOI: 10.3390/genes10100789] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/13/2019] [Accepted: 09/15/2019] [Indexed: 02/04/2023] Open
Abstract
The genus Austrolebias (Cyprinodontiformes: Rivulidae) represents a specious group of taxa following annual life cycles in the neotropical ichthyofauna. They live in temporary ponds and each generation must be completed in a few months, depending on environmental stochasticity. Annual fish survive the dry season through diapausing eggs buried in the substrate of these ponds. A hypothesized bimodal hybrid zone between two taxa of the genus, A. charrua and A. reicherti from Dos Patos Merin lagoon system, was recently proposed based on genetics and morphological analyses. However, hundreds of additional nuclear molecular markers should be used to strongly support this hypothesized bimodal pattern. In the present paper, we conducted RNA-seq-based sequencing of the transcriptomes from pools of individuals of A. charrua, A. reicherti and their putative natural hybrids from the previously characterized hybrid zone. As a result, we identified a set of 111,725 SNP (single nucleotide polymorphism) markers, representing presumably fixed allelic differences among the two species. The present study provided the first panel of 106 SNP markers as a single diagnostic multiplex assay and validated their capacity to reconstruct the patterns of the hybrid zone between both taxa. These nuclear markers combined with Cytb gene and morphological analyses detected a population structure in which some groups among the hybrid swarms showed different level of introgression towards one or the other parental species according to their geographic distribution. High-quality transcriptomes and a large set of gene-linked SNPs should greatly facilitate functional and population genomics studies in the hybrid zone of these endangered species.
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Affiliation(s)
- Graciela García
- Sección Genética Evolutiva, Facultad de Ciencias, UdelaR, Iguá 4225, Montevideo 11400, Uruguay.
| | - Néstor Ríos
- Sección Genética Evolutiva, Facultad de Ciencias, UdelaR, Iguá 4225, Montevideo 11400, Uruguay.
| | - Verónica Gutiérrez
- Sección Genética Evolutiva, Facultad de Ciencias, UdelaR, Iguá 4225, Montevideo 11400, Uruguay.
| | - Sebastián Serra
- Sección Genética Evolutiva, Facultad de Ciencias, UdelaR, Iguá 4225, Montevideo 11400, Uruguay.
- Departamento de Ecología y Evolución, Facultad de Ciencias, UdelaR, Iguá 4225, Montevideo 11400, Uruguay.
- Sección Ictiología, Museo Nacional de Historia Natural, Montevideo 11400, Uruguay.
| | - Marcelo Loureiro
- Departamento de Ecología y Evolución, Facultad de Ciencias, UdelaR, Iguá 4225, Montevideo 11400, Uruguay.
- Sección Ictiología, Museo Nacional de Historia Natural, Montevideo 11400, Uruguay.
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105
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Sujii PS, Cozzolino S, Pinheiro F. Hybridization and geographic distribution shapes the spatial genetic structure of two co-occurring orchid species. Heredity (Edinb) 2019; 123:458-469. [PMID: 31391556 PMCID: PMC6781141 DOI: 10.1038/s41437-019-0254-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/11/2019] [Accepted: 07/17/2019] [Indexed: 11/09/2022] Open
Abstract
Multiple ecological and life-history traits shape the fine-scale spatial genetic structure (FSGS) of a given population. The occurrence in core versus peripheral populations, levels of outcrossing, pollen and seed dispersal, and hybridization are important biological properties that influence the kinship of individuals within populations. We examined spatial genetic structure within 15 populations of Epidendrum fulgens and E. puniceoluteum distributed along a linear gradient of Brazilian coastal vegetation, including both allopatric and sympatric populations where the two orchid species hybridize. We analyzed 581 mapped specimens using nine simple sequence repeat loci, aiming to investigate how geographic distribution and hybridization shape within-population FSGS. A significant increase in FSGS was found towards peripheral populations, compared to core populations. Analysis of short-distance and long-distance components of FSGS identified biparental inbreeding and higher levels of FSGS at peripheral populations, when compared to core populations. In contrast, the relatively high density of reproductive adults in core populations potentially leads to highly overlapping seed and pollen movement, decreasing FSGS. Hybridization was an important factor shaping within-population spatial genetic structure at sympatric sites, decreasing the FSGS observed in parental species. Our results indicate that different ecological forces act in concert to create a gradient of FSGS along species distribution ranges, shaped by extensive levels of intraspecific and interspecific gene exchange.
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Affiliation(s)
| | - Salvatore Cozzolino
- Department of Biology, Complesso Universitario di Monte S. Angelo, Università degli Studi di Napoli Federico II, 80126, Napoli, Italy
| | - Fábio Pinheiro
- Departamento de Biologia Vegetal, Universidade Estadual de Campinas, Instituto de Biologia, Campinas, Brazil.
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106
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Lachmuth S, Molofsky J, Milbrath L, Suda J, Keller SR. Associations between genomic ancestry, genome size and capitula morphology in the invasive meadow knapweed hybrid complex ( Centaurea × moncktonii) in eastern North America. AOB PLANTS 2019; 11:plz055. [PMID: 31632628 PMCID: PMC6790064 DOI: 10.1093/aobpla/plz055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 08/22/2019] [Indexed: 06/10/2023]
Abstract
Plant invasions are prime opportunities for studying hybridization and the nature of species boundaries, but hybrids also complicate the taxonomic treatment and management of introduced taxa. In this study, we use population genomics to estimate the extent of genomic admixture and test for its association with morphology and genome size in a hybrid complex of knapweeds invasive to North America: meadow knapweed (Centaurea × moncktonii) and its parental species (C. jacea and C. nigra). We sampled 20 populations from New York and Vermont, USA, and used genotyping by sequencing to identify single nucleotide polymorphisms in order to estimate genome-wide ancestry and classify individuals into hybrid genotype classes. We then tested for association between degree of genomic introgression and variation in a subset of traits diagnostic for the parental taxa, namely capitula morphology and monoploid genome size. Genomic clustering revealed two clearly defined lineages, as well as many admixed individuals forming a continuous gradation of introgression. Individual assignments to hybrid genotype classes revealed many advanced generation intercrosses and backcrosses, suggesting introgression has been extensive and unimpeded by strong reproductive barriers between taxa. Variation in capitula traits between the two unadmixed, presumed parental, lineages exhibited continuous, and in some cases transgressive, segregation among introgressed hybrids. Genome size was also divergent between lineages, although advanced generation hybrids had smaller genomes relative to additive expectations. Our study demonstrates deep introgression between the porous genomes of a hybrid invasive species complex. In addition to strong associations among genomic ancestry, genome size and morphology, hybrids expressed more extreme phenotypic values for capitula traits and genome size, indicating transgressive segregation, as well as a bias towards smaller genomes, possibly due to genomic downsizing. Future studies will apply these results to experimentally test how introgression, transgressive segregation and genome size reduction interact to confer invasiveness.
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Affiliation(s)
- Susanne Lachmuth
- University of Vermont, Department of Plant Biology, Burlington, VT, USA
- Martin Luther University Halle Wittenberg, Institute of Biology, Geobotany & Botanical Garden, Halle (Saale), Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Jane Molofsky
- University of Vermont, Department of Plant Biology, Burlington, VT, USA
| | - Lindsey Milbrath
- United Sates Department of Agriculture, Agricultural Research Service (USDA-ARS), Ithaca, NY, USA
| | - Jan Suda
- Charles University Prague, Department of Botany, Prague, Czech Republic
- Czech Academy of Sciences, Institute of Botany, Průhonice, Czech Republic
| | - Stephen R Keller
- University of Vermont, Department of Plant Biology, Burlington, VT, USA
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107
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Dittberner H, Becker C, Jiao WB, Schneeberger K, Hölzel N, Tellier A, de Meaux J. Strengths and potential pitfalls of hay transfer for ecological restoration revealed by RAD-seq analysis in floodplain Arabis species. Mol Ecol 2019; 28:3887-3901. [PMID: 31338892 DOI: 10.1111/mec.15194] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 06/21/2019] [Accepted: 07/03/2019] [Indexed: 12/24/2022]
Abstract
Achieving high intraspecific genetic diversity is a critical goal in ecological restoration as it increases the adaptive potential and long-term resilience of populations. Thus, we investigated genetic diversity within and between pristine sites in a fossil floodplain and compared it to sites restored by hay transfer between 1997 and 2014. RAD-seq genotyping revealed that the stenoecious floodplain species Arabis nemorensis is co-occurring with individuals that, based on ploidy, ITS-sequencing and morphology, probably belong to the close relative Arabis sagittata, which has a documented preference for dry calcareous grasslands but has not been reported in floodplain meadows. We show that hay transfer maintains genetic diversity for both species. Additionally, in A. sagittata, transfer from multiple genetically isolated pristine sites resulted in restored sites with increased diversity and admixed local genotypes. In A. nemorensis, transfer did not create novel admixture dynamics because genetic diversity between pristine sites was less differentiated. Thus, the effects of hay transfer on genetic diversity also depend on the genetic make-up of the donor communities of each species, especially when local material is mixed. Our results demonstrate the efficiency of hay transfer for habitat restoration and emphasize the importance of prerestoration characterization of microgeographic patterns of intraspecific diversity of the community to guarantee that restoration practices reach their goal, that is maximize the adaptive potential of the entire restored plant community. Overlooking these patterns may alter the balance between species in the community. Additionally, our comparison of summary statistics obtained from de novo- and reference-based RAD-seq pipelines shows that the genomic impact of restoration can be reliably monitored in species lacking prior genomic knowledge.
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Affiliation(s)
| | - Christian Becker
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Wen-Biao Jiao
- Max-Planck-Institute for Plant Breeding Research, Cologne, Germany
| | | | - Norbert Hölzel
- Institute of Landscape Ecology, University of Münster, Münster, Germany
| | - Aurélien Tellier
- Center of Life and Food Sciences Weihenstephan, Technical University of Munich, Freising, Germany
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108
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Scholz GE, Popescu AA, Taylor MI, Moulton V, Huber KT. OSF-Builder: A New Tool for Constructing and Representing Evolutionary Histories Involving Introgression. Syst Biol 2019; 68:717-729. [PMID: 30668824 DOI: 10.1093/sysbio/syz004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 01/15/2019] [Accepted: 01/15/2019] [Indexed: 11/13/2022] Open
Abstract
Introgression is an evolutionary process which provides an important source of innovation for evolution. Although various methods have been used to detect introgression, very few methods are currently available for constructing evolutionary histories involving introgression. In this article, we propose a new method for constructing such evolutionary histories whose starting point is a species forest (consisting of a collection of lineage trees, usually arising as a collection of clades or monophyletic groups in a species tree), and a gene tree for a specific allele of interest, or allele tree for short. Our method is based on representing introgression in terms of a certain "overlay" of the allele tree over the lineage trees, called an overlaid species forest (OSF). OSFs are similar to phylogenetic networks although a key difference is that they typically have multiple roots because each monophyletic group in the species tree has a different point of origin. Employing a new model for introgression, we derive an efficient algorithm for building OSFs called OSF-Builder that is guaranteed to return an optimal OSF in the sense that the number of potential introgression events is minimized. As well as using simulations to assess the performance of OSF-Builder, we illustrate its use on a butterfly data set in which introgression has been previously inferred. The OSF-Builder software is available for download from https://www.uea.ac.uk/computing/software/OSF-Builder.
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Affiliation(s)
| | | | - Martin I Taylor
- School of Biological Sciences, University of East Anglia, Norwich, UK
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109
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Duarte ME, de Mendonça RS, Skoracka A, Silva ES, Navia D. Integrative taxonomy of Abacarus mites (Eriophyidae) associated with hybrid sugarcane plants, including description of a new species. EXPERIMENTAL & APPLIED ACAROLOGY 2019; 78:373-401. [PMID: 31278610 DOI: 10.1007/s10493-019-00388-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 05/30/2019] [Indexed: 06/09/2023]
Abstract
Phytophagous mites belonging to the Eriophyoidea are extremely diverse and highly host-specific. Their accurate morphological identification is hampered by their reduced size and simplified bodies and by the existence of cryptic species complexes. Previous studies have demonstrated the urgency of applying multisource methods to accurate taxonomic identification of eriophyoid mites, especially species belonging to the genus Abacarus. This genus comprises 65 species, of which 37 are associated with grasses and four with sugarcane Saccharum (Poaceae). Recently, Abacarus specimens very similar to Abacarus sacchari were collected from the sugarcane crop in Brazil; however, their taxonomic placement was uncertain. In this study, we used an integrative approach to determine whether A. aff. sacchari specimens belong to A. sacchari or constitute a cryptic species. Morphological data were combined with molecular phylogeny based on the nucleotide sequences of three markers, one mitochondrial (COI) and two nuclear (D2 region of 28S and ITS). Morphological differences were observed between A. aff. sacchari, A. sacchari and A. doctus. The phylogenetic relationships among these three taxa and the genetic distances separating them revealed an interspecific divergence. The results of the morphological and molecular methods were congruent and supported the existence of a new species: Abacarus neosacchari n. sp. Duarte and Navia, herein described. This species belongs to the Abacarus cryptic species complex associated with sugarcane in the Americas. The results of this study, presenting the occurrence of multiple Abacarus species associated with sugarcane, contribute to the knowledge on plants and mites diversity by adding up one more clue highlighting that plant hybridization can be an important mechanism contributing to the speciation of plant-feeding arthropods.
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Affiliation(s)
- Mércia Elias Duarte
- Embrapa Recursos Genéticos e Biotecnologia, Brasilia, Distrito Federal, 70770-900, Brazil
| | - Renata Santos de Mendonça
- Faculdade de Agronomia e Medicina Veterinária, Universidade de Brasília, Campus Darcy Ribeiro, Brasília, DF, 70297-400, Brazil
| | - Anna Skoracka
- Population Ecology Lab, Faculty of Biology, Institute of Environmental Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, Poznań, 61-614, Poland
| | - Edmilson Santos Silva
- Universidade Federal de Alagoas, Campus Arapiraca, Arapiraca, 57309-005, Brazil
- Universidade Federal de Alagoas, Centro de Ciências Agrárias (CECA), Alagoas, 57100-000, Brazil
| | - Denise Navia
- Embrapa Recursos Genéticos e Biotecnologia, Brasilia, Distrito Federal, 70770-900, Brazil.
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110
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Vidotti MS, Matias FI, Alves FC, Pérez-Rodríguez P, Beltran GA, Burgueño J, Crossa J, Fritsche-Neto R. Maize responsiveness to Azospirillum brasilense: Insights into genetic control, heterosis and genomic prediction. PLoS One 2019; 14:e0217571. [PMID: 31173600 PMCID: PMC6555527 DOI: 10.1371/journal.pone.0217571] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Accepted: 05/14/2019] [Indexed: 12/30/2022] Open
Abstract
Several studies have shown differences in the abilities of maize genotypes to facilitate or impede Azospirillum brasilense colonization and to receive benefits from this association. Hence, our aim was to study the genetic control, heterosis effect and the prediction accuracy of the shoot and root traits of maize in response to A. brasilense. For that, we evaluated 118 hybrids under two contrasting scenarios: i) N stress (control) and ii) N stress plus A. brasilense inoculation. The diallel analyses were performed using mixed model equations, and the genomic prediction models accounted for the general and specific combining ability (GCA and SCA, respectively) and the presence or not of G×E effects. In addition, the genomic models were fitted considering parametric (G-BLUP) and semi-parametric (RKHS) kernels. The genotypes showed significant inoculation effect for five root traits, and the GCA and SCA were significant for both. The GCA in the inoculated treatment presented a greater magnitude than the control, whereas the opposite was observed for SCA. Heterosis was weakly influenced by the inoculation, and the heterozygosity and N status in the plant can have a role in the benefits that can be obtained from this Plant Growth-Promoting Bacteria (PGPB). Prediction accuracies for N stress plus A. brasilense ranged from 0.42 to 0.78, depending on the scenario and trait, and were higher, in most cases, than the non-inoculated treatment. Finally, our findings provide an understanding of the quantitative variation of maize responsiveness to A. brasilense and important insights to be applied in maize breeding aiming the development of superior hybrids for this association.
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Affiliation(s)
- Miriam Suzane Vidotti
- Genetics Department, “Luiz de Queiroz” College of Agriculture, University of São Paulo, Piracicaba, São Paulo, Brazil
| | - Filipe Inácio Matias
- Genetics Department, “Luiz de Queiroz” College of Agriculture, University of São Paulo, Piracicaba, São Paulo, Brazil
| | - Filipe Couto Alves
- Department of Epidemiology & Biostatistics, Michigan State University, East Lansing, Michigan, United States of America
| | | | - Gregório Alvarado Beltran
- Biometrics and Statistics Unit, International Maize and Wheat Improvement Center (CIMMYT), Texcoco, Estado de Mexico, Mexico
| | - Juan Burgueño
- Biometrics and Statistics Unit, International Maize and Wheat Improvement Center (CIMMYT), Texcoco, Estado de Mexico, Mexico
| | - José Crossa
- Biometrics and Statistics Unit, International Maize and Wheat Improvement Center (CIMMYT), Texcoco, Estado de Mexico, Mexico
| | - Roberto Fritsche-Neto
- Genetics Department, “Luiz de Queiroz” College of Agriculture, University of São Paulo, Piracicaba, São Paulo, Brazil
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111
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Voshall A, Moriyama EN. Next-generation transcriptome assembly and analysis: Impact of ploidy. Methods 2019; 176:14-24. [PMID: 31176772 DOI: 10.1016/j.ymeth.2019.06.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 05/30/2019] [Accepted: 06/01/2019] [Indexed: 10/26/2022] Open
Abstract
Whole genome duplications (WGD) occur widely in plants, but the effects of these events impact all branches of life. WGD events have major evolutionary impacts, often leading to major structural changes within the chromosomes and massive changes in gene expression that facilitate rapid speciation and gene diversification. Even for species that currently have diploid genomes, the impact of ancestral duplication events is still present in the genomes, especially in the context of highly similar gene families that are retained from WGD. However, the impact of these ploidies on various bioinformatics workflows has not been studied well. In this review, we overview biological significance of polyploidy in different organisms. We describe the impact of having polyploid transcriptomes on bioinformatics analyses, especially focusing on transcriptome assembly and transcript quantification. We discuss the benefits of using simulated benchmarking data when we examine the performance of various methods. We also present an example strategy to generate simulated allopolyploid transcriptomes and RNAseq datasets and how these benchmark datasets can be used to assess the performance of transcript assembly and quantification methods. Our benchmarking study shows that all transcriptome assembly methods are affected by having polyploid genomes. Quantification accuracy is also impacted by polyploidy depending on the method. These simulated datasets can be adapted for testing, such as, read mapping, variant calling, and differential expression using biologically realistic conditions.
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Affiliation(s)
- Adam Voshall
- Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE 68588, USA; School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588, USA; Department of Computer Science and Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - Etsuko N Moriyama
- Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE 68588, USA; School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588, USA.
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Burge DO, Parker VT, Mulligan M, Sork VL. Influence of a climatic gradient on genetic exchange between two oak species. AMERICAN JOURNAL OF BOTANY 2019; 106:864-878. [PMID: 31216071 DOI: 10.1002/ajb2.1315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 03/27/2019] [Indexed: 06/09/2023]
Abstract
PREMISE In plant groups with limited intrinsic barriers to gene flow, it is thought that environmental conditions can modulate interspecific genetic exchange. Oaks are known for limited barriers to gene flow among closely related species. Here, we use Quercus as a living laboratory in which to pursue a fundamental question in plant evolution: Do environmental gradients restrict or promote genetic exchange between species? METHODS We focused on two North American oaks, the rare Quercus dumosa and the widespread Q. berberidifolia. We sampled intensively along a contact zone in California, USA. We sequenced restriction site-associated DNA markers and measured vegetative phenotype. We tested for genetic exchange, the association with climate, and the effect on phenotype. RESULTS There is evidence for genetic exchange between the species. Admixed plants are found in areas of intermediate climate, while less admixed plants are found at the extremes of the climatic gradient. Genetic and phenotypic patterns are out of phase in the contact zone; some plants display the phenotype of one species but are genetically associated with another. CONCLUSIONS Our results support the hypothesis that a strong climatic gradient can promote genetic exchange between species. The overall weak correlation between genotype and phenotype in the contact zone between the species suggests that genetic exchange can lead to the breakdown of trait combinations used to define species. This incongruency predicts ongoing problems for conservation of Q. dumosa, with implications for conservation of other oaks.
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Affiliation(s)
- Dylan O Burge
- Department of Ecology and Evolutionary Biology, University of California, Box 957239, Los Angeles, California, 90095-7239, USA
- 554 Vallombrosa Avenue, P.O. Box 418, Chico, California, 95927, USA
| | - V Thomas Parker
- San Francisco State University, 1600 Holloway Avenue, San Francisco, California, 94132, USA
| | - Margaret Mulligan
- San Diego Natural History Museum, Balboa Park, 1788 El Prado, San Diego, California, 92101, USA
| | - Victoria L Sork
- Department of Ecology and Evolutionary Biology, University of California, Box 957239, Los Angeles, California, 90095-7239, USA
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113
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Affiliation(s)
- Jesse N Weber
- Department of Biological Sciences, University of Alaska, Anchorage, AK, USA.
| | - Wenfei Tong
- Department of Biological Sciences, University of Alaska, Anchorage, AK, USA
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114
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Paštová L, Belyayev A, Mahelka V. Molecular cytogenetic characterisation of Elytrigia ×mucronata, a natural hybrid of E. intermedia and E. repens (Triticeae, Poaceae). BMC PLANT BIOLOGY 2019; 19:230. [PMID: 31151385 PMCID: PMC6544950 DOI: 10.1186/s12870-019-1806-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 04/26/2019] [Indexed: 05/18/2023]
Abstract
BACKGROUND Interspecific hybridisation resulting in polyploidy is one of the major driving forces in plant evolution. Here, we present data from the molecular cytogenetic analysis of three cytotypes of Elytrigia ×mucronata using sequential fluorescence (5S rDNA, 18S rDNA and pSc119.2 probes) and genomic in situ hybridisation (four genomic probes of diploid taxa, i.e., Aegilops, Dasypyrum, Hordeum and Pseudoroegneria). RESULTS The concurrent presence of Hordeum (descended from E. repens) and Dasypyrum + Aegilops (descended from E. intermedia) chromosome sets in all cytotypes of E. ×mucronata confirmed the assumed hybrid origin of the analysed plants. The following different genomic constitutions were observed for E. ×mucronata. Hexaploid plants exhibited three chromosome sets from Pseudoroegneria and one chromosome set each from Aegilops, Hordeum and Dasypyrum. Heptaploid plants harboured the six chromosome sets of the hexaploid plants and an additional Pseudoroegneria chromosome set. Nonaploid cytotypes differed in their genomic constitutions, reflecting different origins through the fusion of reduced and unreduced gametes. The hybridisation patterns of repetitive sequences (5S rDNA, 18S rDNA, and pSc119.2) in E. ×mucronata varied between and within cytotypes. Chromosome alterations that were not identified in the parental species were found in both heptaploid and some nonaploid plants. CONCLUSIONS The results confirmed that both homoploid hybridisation and heteroploid hybridisation that lead to the coexistence of four different haplomes within single hybrid genomes occur in Elytrigia allopolyploids. The chromosomal alterations observed in both heptaploid and some nonaploid plants indicated that genome restructuring occurs during and/or after the hybrids arose. Moreover, a specific chromosomal translocation detected in one of the nonaploids indicated that it was not a primary hybrid. Therefore, at least some of the hybrids are fertile. Hybridisation in Triticeae allopolyploids clearly and significantly contributes to genomic diversity. Different combinations of parental haplomes coupled with chromosomal alterations may result in the establishment of unique lineages, thus providing raw material for selection.
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Affiliation(s)
- Ladislava Paštová
- Institute of Botany, Czech Academy of Sciences, Zámek 1, 252 43 Průhonice, Czech Republic
- Department of Botany, Charles University, Benátská 2, 128 01 Prague, Czech Republic
| | - Alexander Belyayev
- Institute of Botany, Czech Academy of Sciences, Zámek 1, 252 43 Průhonice, Czech Republic
| | - Václav Mahelka
- Institute of Botany, Czech Academy of Sciences, Zámek 1, 252 43 Průhonice, Czech Republic
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115
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Oakley CG, Lundemo S, Ågren J, Schemske DW. Heterosis is common and inbreeding depression absent in natural populations of
Arabidopsis thaliana. J Evol Biol 2019; 32:592-603. [DOI: 10.1111/jeb.13441] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 02/23/2019] [Accepted: 03/11/2019] [Indexed: 01/09/2023]
Affiliation(s)
| | - Sverre Lundemo
- Plant Ecology and Evolution Department of Ecology and Genetics Evolutionary Biology Centre Uppsala University Uppsala Sweden
| | - Jon Ågren
- Plant Ecology and Evolution Department of Ecology and Genetics Evolutionary Biology Centre Uppsala University Uppsala Sweden
| | - Douglas W. Schemske
- Department of Plant Biology W. K. Kellogg Biological Station Michigan State University East Lansing Michigan
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116
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Yan LJ, Burgess KS, Zheng W, Tao ZB, Li DZ, Gao LM. Incomplete reproductive isolation between Rhododendron taxa enables hybrid formation and persistence. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2019; 61:433-448. [PMID: 30192058 DOI: 10.1111/jipb.12718] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Accepted: 09/06/2018] [Indexed: 06/08/2023]
Abstract
The evolutionary consequences of hybridization ultimately depend on the magnitude of reproductive isolation between hybrids and their parents. We evaluated the relative contributions of pre- and post-zygotic barriers to reproduction for hybrid formation, hybrid persistence and potential for reproductive isolation of hybrids formed between two Rhododendron species, R. spiciferum and R. spinuliferum. Our study established that incomplete reproductive isolation promotes hybrid formation and persistence and delays hybrid speciation. All pre-zygotic barriers to reproduction leading to hybrid formation are incomplete: parental species have overlapping flowering; they share the same pollinators; reciprocal assessments of pollen tube germination and growth do not differ among parents. The absence of post-zygotic barriers between parental taxa indicates that the persistence of hybrids is likely. Reproductive isolation was incomplete between hybrids and parents in all cases studied, although asymmetric differences in reproductive fitness were prevalent and possibly explain the genetic structure of natural hybrid swarms where hybridization is known to be bidirectional but asymmetric. Introgression, rather than speciation, is a probable evolutionary outcome of hybridization between the two Rhododendron taxa. Our study provides insights into understanding the evolutionary implications of natural hybridization in woody plants.
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Affiliation(s)
- Li-Jun Yan
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650201, China
- Germplasm Bank of Wild Species, Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650201, China
- Kunming College of Life Science, University of the Chinese Academy of Sciences, Kunming 650201, China
- College of Vocational and Technical Education, Yunnan Normal University, Kunming 650092, China
| | - Kevin S Burgess
- Department of Biology, College of Letters & Sciences, Columbus State University, University System of Georgia, 31907-5645 Columbus, GA, USA
| | - Wei Zheng
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650201, China
- Kunming College of Life Science, University of the Chinese Academy of Sciences, Kunming 650201, China
| | - Zhi-Bin Tao
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650201, China
- Kunming College of Life Science, University of the Chinese Academy of Sciences, Kunming 650201, China
| | - De-Zhu Li
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650201, China
- Germplasm Bank of Wild Species, Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650201, China
- Kunming College of Life Science, University of the Chinese Academy of Sciences, Kunming 650201, China
| | - Lian-Ming Gao
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, the Chinese Academy of Sciences, Kunming 650201, China
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117
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Carrió E, Güemes J. Can the problem of hybridization in threatened species be evaluated using a fieldwork research? A case study in snapdragons. J Nat Conserv 2019. [DOI: 10.1016/j.jnc.2019.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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118
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Nagamitsu T, Shimizu H, Aizawa M, Nakanishi A. An admixture of Quercus dentata in the coastal ecotype of Q. mongolica var. crispula in northern Hokkaido and genetic and environmental effects on their traits. JOURNAL OF PLANT RESEARCH 2019; 132:211-222. [PMID: 30604174 DOI: 10.1007/s10265-018-01079-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 12/16/2018] [Indexed: 06/09/2023]
Abstract
In northern Japan, coastal oak forests consist of Quercus dentata (Qd) on the coastal side and Q. mongolica var. crispula (Qc) on the inland side. In the forests of northern Hokkaido, Qd is rare, and a coastal ecotype of Qc with some Qd-like traits grows on the coastal side. To reveal the genetic background of this ecotype, nuclear microsatellite genotypes in closely related oak taxa were obtained from the Eurasian continent, Sakhalin, and Hokkaido. The clustering of these genotypes suggests an admixture of Qd in the coastal ecotype of Qc. Next, we evaluated the effects of admixture and coastal stress on the leaf and shoot traits of Qc and Qd along coastal-inland gradients in northern Hokkaido. The admixture of Qd in Qc was quantified by the Qd ancestry proportions. Coastal stress causes bud mortality in the upper parts of shoots and was quantified by the survival patterns of buds in shoots. The genetic and environmental effects on the traits at Qd-abundant and Qd-rare sites were estimated using linear mixed models. The genetic effect was detected in all traits. Both genetic and environmental effects were detected in most traits. Some traits differed between Qd-abundant and Qd-rare sites in addition to these effects, indicating more Qd-like traits at Qd-rare sites. The findings suggest that an admixture of Qd characterizes the genetic background of the coastal ecotype of Qc and that not only the coastal stress but also the genetic background is responsible for the leaf and shoot traits of Qc and Qd in northern Hokkaido.
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Affiliation(s)
- Teruyoshi Nagamitsu
- Forest Research and Management Organization, Forestry and Forest Products Research Institute, Hokkaido Research Center, Sapporo, 062-8516, Japan.
| | - Hajime Shimizu
- Hokkaido Research Organization, Forestry Research Institute, Greenery Research and Information Center, Bibai, 079-0198, Japan
| | - Mineaki Aizawa
- Department of Forest Science, Faculty of Agriculture, Utsunomiya University, Utsunomiya, 321-8505, Japan
| | - Atsushi Nakanishi
- Forest Research and Management Organization, Forestry and Forest Products Research Institute, Hokkaido Research Center, Sapporo, 062-8516, Japan
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119
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Brennan AC, Hiscock SJ, Abbott RJ. Completing the hybridization triangle: the inheritance of genetic incompatibilities during homoploid hybrid speciation in ragworts ( Senecio). AOB PLANTS 2019; 11:ply078. [PMID: 30740200 PMCID: PMC6360072 DOI: 10.1093/aobpla/ply078] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 01/04/2019] [Indexed: 05/24/2023]
Abstract
A new homoploid hybrid lineage needs to establish a degree of reproductive isolation from its parent species if it is to persist as an independent entity, but the role hybridization plays in this process is known in only a handful of cases. The homoploid hybrid ragwort species, Senecio squalidus (Oxford ragwort), originated following the introduction of hybrid plants to the UK approximately 320 years ago. The source of the hybrid plants was from a naturally occurring hybrid zone between S. aethnensis and S. chrysanthemifolius on Mount Etna, Sicily. Previous studies of the parent species found evidence for multiple incompatibility loci causing transmission ratio distortion of genetic markers in their hybrid progeny. This study closes the hybridization triangle by reporting a genetic mapping analysis of the remaining two paired cross combinations between S. squalidus and its parents. Genetic maps produced from F2 mapping families were generally collinear but with half of the linkage groups showing evidence of genomic reorganization between genetic maps. The new maps produced from crosses between S. squalidus and each parent showed multiple incompatibility loci distributed across the genome, some of which co-locate with previously reported incompatibility loci between the parents. These findings suggest that this young homoploid hybrid species has inherited a unique combination of genomic rearrangements and incompatibilities from its parents that contribute to its reproductive isolation.
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Affiliation(s)
- Adrian C Brennan
- Department of Biosciences, University of Durham, South Road, Durham, UK
- School of Biology, University of St Andrews, St Andrews, Fife, UK
| | - Simon J Hiscock
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | - Richard J Abbott
- School of Biology, University of St Andrews, St Andrews, Fife, UK
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120
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Cai L, Xi Z, Amorim AM, Sugumaran M, Rest JS, Liu L, Davis CC. Widespread ancient whole-genome duplications in Malpighiales coincide with Eocene global climatic upheaval. THE NEW PHYTOLOGIST 2019; 221:565-576. [PMID: 30030969 PMCID: PMC6265113 DOI: 10.1111/nph.15357] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 06/21/2018] [Indexed: 05/12/2023]
Abstract
Whole-genome duplications (WGDs) are widespread and prevalent in vascular plants and frequently coincide with major episodes of global and climatic upheaval, including the mass extinction at the Cretaceous-Tertiary boundary (c. 65 Ma) and during more recent periods of global aridification in the Miocene (c. 10-5 Ma). Here, we explore WGDs in the diverse flowering plant clade Malpighiales. Using transcriptomes and complete genomes from 42 species, we applied a multipronged phylogenomic pipeline to identify, locate, and determine the age of WGDs in Malpighiales using three means of inference: distributions of synonymous substitutions per synonymous site (Ks ) among paralogs, phylogenomic (gene tree) reconciliation, and a likelihood-based gene-count method. We conservatively identify 22 ancient WGDs, widely distributed across Malpighiales subclades. Importantly, these events are clustered around the Eocene-Paleocene transition (c. 54 Ma), during which time the planet was warmer and wetter than any period in the Cenozoic. These results establish that the Eocene Climatic Optimum likely represents a previously unrecognized period of prolific WGDs in plants, and lends further support to the hypothesis that polyploidization promotes adaptation and enhances plant survival during episodes of global change, especially for tropical organisms like Malpighiales, which have tight thermal tolerances.
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Affiliation(s)
- Liming Cai
- Department of Organismic and Evolutionary Biology, Harvard University Herbaria, 22 Divinity Avenue, Cambridge, MA 02138, USA
| | - Zhenxiang Xi
- Department of Organismic and Evolutionary Biology, Harvard University Herbaria, 22 Divinity Avenue, Cambridge, MA 02138, USA
- Key Laboratory of Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China
| | - André M. Amorim
- Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz, Ilhéus, 45.662-900, Bahia, Brazil
| | - M. Sugumaran
- Rimba Ilmu Botanic Garden, Institute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Joshua S. Rest
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794, USA
| | - Liang Liu
- Department of Statistics and Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA
| | - Charles C. Davis
- Key Laboratory of Bio-resource and Eco-environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China
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121
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Mota MR, Pinheiro F, Leal BSS, Wendt T, Palma-Silva C. The role of hybridization and introgression in maintaining species integrity and cohesion in naturally isolated inselberg bromeliad populations. PLANT BIOLOGY (STUTTGART, GERMANY) 2019; 21:122-132. [PMID: 30195257 DOI: 10.1111/plb.12909] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 09/06/2018] [Indexed: 05/02/2023]
Abstract
Hybridization is a widespread phenomenon present in numerous lineages across the tree of life. Its evolutionary consequences range from effects on the origin and maintenance, to the loss of biodiversity. We studied genetic diversity and intra- and interspecific gene flow between two sympatric populations of closely-related species, Pitcairnia flammea and P. corcovadensis (Bromeliaceae), which are adapted to naturally fragmented Neotropical inselbergs, based on nuclear and plastidial DNA. Our main results indicate a strong reproductive isolation barrier, although low levels of interspecific gene flow were observed in both sympatric populations. The low rates of intraspecific gene flow observed for both P. corcovadensis and P. flammea populations corroborate the increasing body of evidence that inselberg bromeliad species are maintained as discrete evolutionary units despite the presence of low genetic connectivity. Nuclear patterns of genetic diversity and gene flow revealed that hybridization and introgression might not cause species extinction via genetic assimilation of the rare P. corcovadensis. In the face of reduced intraspecific gene exchange, hybridization and introgression may be important aspects of the Pitcairnia diversification process, with a positive evolutionary impact at the bromeliad community level, and thus contribute to increasing and maintaining genetic diversity in local isolated inselberg populations.
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Affiliation(s)
- M R Mota
- Departamento de Ecologia, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, Brazil
| | - F Pinheiro
- Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, Brazil
| | - B S S Leal
- Departamento de Ecologia, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, Brazil
| | - T Wendt
- Departamento de Botânica, Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - C Palma-Silva
- Departamento de Ecologia, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, Brazil
- Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, Brazil
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Castillo-Mendoza E, Salinas-Sánchez D, Valencia-Cuevas L, Zamilpa A, Tovar-Sánchez E. Natural hybridisation among Quercus glabrescens, Q. rugosa and Q. obtusata (Fagaceae): Microsatellites and secondary metabolites markers. PLANT BIOLOGY (STUTTGART, GERMANY) 2019; 21:110-121. [PMID: 30117248 DOI: 10.1111/plb.12899] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 08/12/2018] [Indexed: 06/08/2023]
Abstract
Natural hybridisation has significant ecological, genetic and evolutionary consequences altering morphological and chemical characters of individuals. Quercus glabrescens, Q. rugosa and Q. obtusata are white oak species well separated by their morphological characters when they occur in allopatry in Mexican temperate forests. However, in sympatry, individuals with atypical morphology have been observed, suggesting hybridisation events. In this study, we determined, with microsatellites and secondary metabolites, if interspecific gene flow occurs when these three oak species coexist in sympatry. In total, 180 individuals belonging to seven populations [three allopatric (one for each parental species) and four sympatric sites] were analysed. Allopatric populations represent well-defined genetic groups and the sympatric populations showed genetic evidence of hybridisation between Q. glabrescens × Q. rugosa and Q. glabrescens × Q. obtusata. The hybridisation percentage varied between sites and combination of involved species. We registered the presence of unique flavonoid compounds for Q. glabrescens (caffeic acid and flavonol 2), Q. rugosa (flavonol 5) and Q. obtusata (flavonol 1). Three compounds (quercetin rhamnoside, flavonol 3 and alkyl coumarate) were expressed in all taxa. Finally, the hybrid genotypes identified in this study (Q. glabrescens × Q. rugosa and Q. glabrescens × Q. obtusata) showed specific chemical profiles, resulting from a combination of those of their parental species. These results show that hybridisation events between these oak species alter chemical expression of secondary metabolites, creating a mosaic of resources and conditions that provide the substrate for different combinations of foliar-associated species such as herbivores, endophytic fungi or epiphyte plants.
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Affiliation(s)
- E Castillo-Mendoza
- Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, CdMx, México
- Laboratorio de Marcadores Moleculares, Centro de Investigación en Biodiversidad y Conservación, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México
| | - D Salinas-Sánchez
- Laboratorio de Fitoquímica, Centro de Investigación en Biodiversidad y Conservación, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México
| | - L Valencia-Cuevas
- Laboratorio de Marcadores Moleculares, Centro de Investigación en Biodiversidad y Conservación, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México
| | - A Zamilpa
- Centro de Investigación Biomédica del Sur (CIBIS-IMSS), Xochitepec, Morelos, México
| | - E Tovar-Sánchez
- Laboratorio de Marcadores Moleculares, Centro de Investigación en Biodiversidad y Conservación, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México
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Balakrishnan D, Surapaneni M, Mesapogu S, Neelamraju S. Development and use of chromosome segment substitution lines as a genetic resource for crop improvement. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2019; 132:1-25. [PMID: 30483819 DOI: 10.1007/s00122-018-3219-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 10/24/2018] [Indexed: 05/27/2023]
Abstract
CSSLs are a complete library of introgression lines with chromosomal segments of usually a distant genotype in an adapted background and are valuable genetic resources for basic and applied research on improvement of complex traits. Chromosome segment substitution lines (CSSLs) are genetic stocks representing the complete genome of any genotype in the background of a cultivar as overlapping segments. Ideally, each CSSL has a single chromosome segment from the donor with a maximum recurrent parent genome recovered in the background. CSSL development program requires population-wide backcross breeding and genome-wide marker-assisted selection followed by selfing. Each line in a CSSL library has a specific marker-defined large donor segment. CSSLs are evaluated for any target phenotype to identify lines significantly different from the parental line. These CSSLs are then used to map quantitative trait loci (QTLs) or causal genes. CSSLs are valuable prebreeding tools for broadening the genetic base of existing cultivars and harnessing the genetic diversity from the wild- and distant-related species. These are resources for genetic map construction, mapping QTLs, genes or gene interactions and their functional analysis for crop improvement. In the last two decades, the utility of CSSLs in identification of novel genomic regions and QTL hot spots influencing a wide range of traits has been well demonstrated in food and commercial crops. This review presents an overview of how CSSLs are developed, their status in major crops and their use in genomic studies and gene discovery.
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Affiliation(s)
- Divya Balakrishnan
- ICAR- National Professor Project, ICAR- Indian Institute of Rice Research, Hyderabad, India
| | - Malathi Surapaneni
- ICAR- National Professor Project, ICAR- Indian Institute of Rice Research, Hyderabad, India
| | - Sukumar Mesapogu
- ICAR- National Professor Project, ICAR- Indian Institute of Rice Research, Hyderabad, India
| | - Sarla Neelamraju
- ICAR- National Professor Project, ICAR- Indian Institute of Rice Research, Hyderabad, India.
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Roda F, Hopkins R. Correlated evolution of self and interspecific incompatibility across the range of a Texas wildflower. THE NEW PHYTOLOGIST 2019; 221:553-564. [PMID: 29992588 DOI: 10.1111/nph.15340] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 06/10/2018] [Indexed: 06/08/2023]
Abstract
Selection to prevent interspecific mating can cause an increase or a decrease in self-pollination in sympatric populations. Characterizing the geographical variation in self and interspecific incompatibilities within a species can reveal if and how the evolution of self and interspecific mate choice are linked. We used controlled pollinations to characterize the variation in self and interspecific incompatibility across 29 populations of Phlox drummondii. We evaluated seed set from these pollinations and described the developmental timing of variation in pollen-pistil compatibility. There is extensive quantitative variation in self-incompatibility and interspecific-incompatibility with its close congener P. cuspidata. Phlox drummondii populations that co-occur and hybridize with P. cuspidata have significantly higher interspecific incompatibility and self-incompatibility than geographically isolated P. drummondii populations. The strength of self and interspecific incompatibility is significantly correlated among individuals and the strength of both incompatibilities is explained by the success of pollen adhesion to the stigma. The correlated strength of self and interspecific incompatibility across the range of P. drummondii and the concurrent developmental timing of the pollen-pistil interaction, suggests these incompatibilities have an overlapping molecular mechanism. The geographical distribution of variation in incompatibilities indicates that this mechanistic link between incompatibilities may affect the evolution of mate choice in plants.
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Affiliation(s)
- Federico Roda
- Department of Organismic and Evolutionary Biology, Harvard University, 22 Divinity Avenue, Cambridge, MA, 02138, USA
- The Arnold Arboretum, Harvard University, 1300 Centre St, Boston, MA, 02131, USA
| | - Robin Hopkins
- Department of Organismic and Evolutionary Biology, Harvard University, 22 Divinity Avenue, Cambridge, MA, 02138, USA
- The Arnold Arboretum, Harvard University, 1300 Centre St, Boston, MA, 02131, USA
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Mitochondrial Genome Variation Affects Multiple Respiration and Nonrespiration Phenotypes in Saccharomyces cerevisiae. Genetics 2018; 211:773-786. [PMID: 30498022 DOI: 10.1534/genetics.118.301546] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 11/20/2018] [Indexed: 02/07/2023] Open
Abstract
Mitochondrial genome variation and its effects on phenotypes have been widely analyzed in higher eukaryotes but less so in the model eukaryote Saccharomyces cerevisiae Here, we describe mitochondrial genome variation in 96 diverse S. cerevisiae strains and assess associations between mitochondrial genotype and phenotypes as well as nuclear-mitochondrial epistasis. We associate sensitivity to the ATP synthase inhibitor oligomycin with SNPs in the mitochondrially encoded ATP6 gene. We describe the use of iso-nuclear F1 pairs, the mitochondrial genome equivalent of reciprocal hemizygosity analysis, to identify and analyze mitochondrial genotype-dependent phenotypes. Using iso-nuclear F1 pairs, we analyze the oligomycin phenotype-ATP6 association and find extensive nuclear-mitochondrial epistasis. Similarly, in iso-nuclear F1 pairs, we identify many additional mitochondrial genotype-dependent respiration phenotypes, for which there was no association in the 96 strains, and again find extensive nuclear-mitochondrial epistasis that likely contributes to the lack of association in the 96 strains. Finally, in iso-nuclear F1 pairs, we identify novel mitochondrial genotype-dependent nonrespiration phenotypes: resistance to cycloheximide, ketoconazole, and copper. We discuss potential mechanisms and the implications of mitochondrial genotype and of nuclear-mitochondrial epistasis effects on respiratory and nonrespiratory quantitative traits.
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White OW, Reyes-Betancort A, Chapman MA, Carine MA. Independent homoploid hybrid speciation events in the Macaronesian endemic genus Argyranthemum. Mol Ecol 2018; 27:4856-4874. [DOI: 10.1111/mec.14889] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 08/29/2018] [Accepted: 09/26/2018] [Indexed: 01/03/2023]
Affiliation(s)
- Oliver W. White
- Algae, Fungi and Plants Division; Department of Life Sciences; The Natural History Museum; London UK
- Biological Sciences; University of Southampton; Southampton UK
| | | | - Mark A. Chapman
- Biological Sciences; University of Southampton; Southampton UK
| | - Mark A. Carine
- Algae, Fungi and Plants Division; Department of Life Sciences; The Natural History Museum; London UK
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Samarasinghe H, Xu J. Hybrids and hybridization in the Cryptococcus neoformans and Cryptococcus gattii species complexes. INFECTION GENETICS AND EVOLUTION 2018; 66:245-255. [PMID: 30342094 DOI: 10.1016/j.meegid.2018.10.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 09/28/2018] [Accepted: 10/16/2018] [Indexed: 12/29/2022]
Abstract
The basidiomycetous yeasts of the Cryptococcus neoformans and Cryptococcus gattii species complexes (CNSC and CGSC respectively) are the causative agents of cryptococcosis, a set of life-threatening diseases affecting the central nervous system, lungs, skin, and other body sites of humans and other mammals. Both the CNSC and CGSC can be subdivided into varieties, serotypes, molecular types, and lineages based on structural variations, molecular characteristics and genetic sequences. Hybridization between the haploid lineages within and between the two species complexes is known to occur in natural and clinical settings, giving rise to intraspecific and interspecific diploid/aneuploid hybrid strains. Since their initial discovery in 1977, cryptococcal hybrids have been increasingly discovered in both clinical and environmental settings with over 30% of all cryptococcal infections in some regions of Europe being caused by hybrid strains. This review summarizes the major findings to date on cryptococcal hybrids, including their possible origins, prevalence, genomic profiles and phenotypic characteristics. Our analyses suggest that CNSC and CGSC can be an excellent model system for studying fungal hybridization.
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Affiliation(s)
- Himeshi Samarasinghe
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - Jianping Xu
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada.
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Chhatre VE, Evans LM, DiFazio SP, Keller SR. Adaptive introgression and maintenance of a trispecies hybrid complex in range‐edge populations of
Populus. Mol Ecol 2018; 27:4820-4838. [DOI: 10.1111/mec.14820] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 07/19/2018] [Accepted: 07/20/2018] [Indexed: 12/16/2022]
Affiliation(s)
- Vikram E. Chhatre
- Department of Plant Biology University of Vermont Burlington Vermont
| | - Luke M. Evans
- Department of Ecology and Evolutionary Biology Institute of Behavioral Genetics University of Colorado Boulder Colorado
| | | | - Stephen R. Keller
- Department of Plant Biology University of Vermont Burlington Vermont
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129
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Feurtey A, Stukenbrock EH. Interspecific Gene Exchange as a Driver of Adaptive Evolution in Fungi. Annu Rev Microbiol 2018; 72:377-398. [DOI: 10.1146/annurev-micro-090817-062753] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Throughout evolutionary history in the kingdom Fungi, taxa have exchanged genetic information among species, as revealed in particular by analyses of genome sequences. In fungi, hybridization can occur by sexual mating or by fusion of vegetative structures giving rise to new species or leaving traces of introgression in the genome. Furthermore, gene exchange can occur by horizontal gene transfer between species and can even include organisms outside the kingdom Fungi. In several cases, interspecific gene exchange has been instrumental in rapid adaptive evolution of fungal species and has notably played a role in the emergence of new pathogens. Here we summarize mechanisms and examples of gene exchange in fungi with a particular focus on the genomic context. We emphasize the need for and potential of applying population genetic approaches to better understand the processes and the impact of interspecific gene exchange in rapid adaptive evolution and species diversification. The broad occurrence of gene exchange among fungal species challenges our species concepts in the kingdom Fungi.
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Affiliation(s)
- Alice Feurtey
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany;,
| | - Eva H. Stukenbrock
- Environmental Genomics, Max Planck Institute for Evolutionary Biology, 24306 Plön, Germany;,
- Environmental Genomics, Christian-Albrechts University of Kiel, 24118 Kiel, Germany
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130
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Xue HJ, Segraves KA, Wei J, Zhang B, Nie RE, Li WZ, Yang XK. Chemically mediated sexual signals restrict hybrid speciation in a flea beetle. Behav Ecol 2018. [DOI: 10.1093/beheco/ary105] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- Huai-Jun Xue
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Kari A Segraves
- Department of Biology, Syracuse University, Syracuse, NY, USA
- Archbold Biological Station, Venus, FL, USA
| | - Jing Wei
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Bin Zhang
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Rui-E Nie
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Wen-Zhu Li
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Xing-Ke Yang
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
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131
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Schrider DR, Ayroles J, Matute DR, Kern AD. Supervised machine learning reveals introgressed loci in the genomes of Drosophila simulans and D. sechellia. PLoS Genet 2018; 14:e1007341. [PMID: 29684059 PMCID: PMC5933812 DOI: 10.1371/journal.pgen.1007341] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 05/03/2018] [Accepted: 03/28/2018] [Indexed: 12/30/2022] Open
Abstract
Hybridization and gene flow between species appears to be common. Even though it is clear that hybridization is widespread across all surveyed taxonomic groups, the magnitude and consequences of introgression are still largely unknown. Thus it is crucial to develop the statistical machinery required to uncover which genomic regions have recently acquired haplotypes via introgression from a sister population. We developed a novel machine learning framework, called FILET (Finding Introgressed Loci via Extra-Trees) capable of revealing genomic introgression with far greater power than competing methods. FILET works by combining information from a number of population genetic summary statistics, including several new statistics that we introduce, that capture patterns of variation across two populations. We show that FILET is able to identify loci that have experienced gene flow between related species with high accuracy, and in most situations can correctly infer which population was the donor and which was the recipient. Here we describe a data set of outbred diploid Drosophila sechellia genomes, and combine them with data from D. simulans to examine recent introgression between these species using FILET. Although we find that these populations may have split more recently than previously appreciated, FILET confirms that there has indeed been appreciable recent introgression (some of which might have been adaptive) between these species, and reveals that this gene flow is primarily in the direction of D. simulans to D. sechellia. Understanding the extent to which species or diverged populations hybridize in nature is crucially important if we are to understand the speciation process. Accordingly numerous research groups have developed methodology for finding the genetic evidence of such introgression. In this report we develop a supervised machine learning approach for uncovering loci which have introgressed across species boundaries. We show that our method, FILET, has greater accuracy and power than competing methods in discovering introgression, and in addition can detect the directionality associated with the gene flow between species. Using whole genome sequences from Drosophila simulans and Drosophila sechellia we show that FILET discovers quite extensive introgression between these species that has occurred mostly from D. simulans to D. sechellia. Our work highlights the complex process of speciation even within a well-studied system and points to the growing importance of supervised machine learning in population genetics.
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Affiliation(s)
- Daniel R. Schrider
- Department of Genetics, Rutgers University, Piscataway, New Jersey, United States of America
- Human Genetics Institute of New Jersey, Rutgers University, Piscataway, New Jersey, United States of America
- * E-mail:
| | - Julien Ayroles
- Ecology and Evolutionary Biology Department, Princeton University, Princeton, New Jersey, United States of America
- Lewis Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Daniel R. Matute
- Biology Department, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Andrew D. Kern
- Department of Genetics, Rutgers University, Piscataway, New Jersey, United States of America
- Human Genetics Institute of New Jersey, Rutgers University, Piscataway, New Jersey, United States of America
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Abstract
Helicoverpa armigera is a major agricultural and horticultural pest that recently spread from its historical distribution throughout much of the Old World to the Americas, where it is already causing hundreds of millions of dollars in damage every year. The species is notoriously quick to generate and disseminate pesticide resistance throughout its range and has a wider host range than the native Helicoverpa zea. Hybridization between the two species increases the opportunity for novel, agriculturally problematic ecotypes to emerge and spread through the Americas. Within the mega-pest lineage of heliothine moths are a number of polyphagous, highly mobile species for which the exchange of adaptive traits through hybridization would affect their properties as pests. The recent invasion of South America by one of the most significant agricultural pests, Helicoverpa armigera, raises concerns for the formation of novel combinations of adaptive genes following hybridization with the closely related Helicoverpa zea. To investigate the propensity for hybridization within the genus Helicoverpa, we carried out whole-genome resequencing of samples from six species, focusing in particular upon H. armigera population structure and its relationship with H. zea. We show that both H. armigera subspecies have greater genetic diversity and effective population sizes than do the other species. We find no signals for gene flow among the six species, other than between H. armigera and H. zea, with nine Brazilian individuals proving to be hybrids of those two species. Eight had largely H. armigera genomes with some introgressed DNA from H. zea scattered throughout. The ninth resembled an F1 hybrid but with stretches of homozygosity for each parental species that reflect previous hybridization. Regions homozygous for H. armigera-derived DNA in this individual included one containing a gustatory receptor and esterase genes previously associated with host range, while another encoded a cytochrome P450 that confers insecticide resistance. Our data point toward the emergence of novel hybrid ecotypes and highlight the importance of monitoring H. armigera genotypes as they spread through the Americas.
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Roberts WR, Roalson EH. Phylogenomic analyses reveal extensive gene flow within the magic flowers (Achimenes). AMERICAN JOURNAL OF BOTANY 2018; 105:726-740. [PMID: 29702729 DOI: 10.1002/ajb2.1058] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 02/02/2018] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY The Neotropical Gesneriaceae is a lineage known for its colorful and diverse flowers, as well as an extensive history of intra- and intergeneric hybridization, particularly among Achimenes (the magic flowers) and other members of subtribe Gloxiniinae. Despite numerous studies seeking to elucidate the evolutionary relationships of these lineages, relatively few have sought to infer specific patterns of gene flow despite evidence of widespread hybridization. METHODS To explore the utility of phylogenomic data for reassessing phylogenetic relationships and inferring patterns of gene flow among species of Achimenes, we sequenced 12 transcriptomes. We used a variety of methods to infer the species tree, examine gene tree discordance, and infer patterns of gene flow. KEY RESULTS Phylogenomic analyses resolve clade relationships at the crown of the lineage with strong support. In contrast to previous analyses, we recovered strong support for several new relationships despite a significant amount of gene tree discordance. We present evidence for at least two introgression events between two species pairs that share pollinators, and suggest that the species status of Achimenes admirabilis be reexamined. CONCLUSIONS Our study demonstrates the utility of transcriptome data for phylogenomic analyses, and inferring patterns of gene flow despite gene tree discordance. Moreover, these data provide another example of prevalent interspecific gene flow among Neotropical plants that share pollinators.
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Affiliation(s)
- Wade R Roberts
- Molecular Plant Sciences Graduate Program, Washington State University, Pullman, Washington, 99164-1030, USA
- School of Biological Sciences, Washington State University, Pullman, Washington, 99164-4236, USA
| | - Eric H Roalson
- Molecular Plant Sciences Graduate Program, Washington State University, Pullman, Washington, 99164-1030, USA
- School of Biological Sciences, Washington State University, Pullman, Washington, 99164-4236, USA
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Pease JB, Brown JW, Walker JF, Hinchliff CE, Smith SA. Quartet Sampling distinguishes lack of support from conflicting support in the green plant tree of life. AMERICAN JOURNAL OF BOTANY 2018; 105:385-403. [PMID: 29746719 DOI: 10.1002/ajb2.1016] [Citation(s) in RCA: 121] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 09/05/2017] [Indexed: 05/21/2023]
Abstract
PREMISE OF THE STUDY Phylogenetic support has been difficult to evaluate within the green plant tree of life partly due to a lack of specificity between conflicted versus poorly informed branches. As data sets continue to expand in both breadth and depth, new support measures are needed that are more efficient and informative. METHODS We describe the Quartet Sampling (QS) method, a quartet-based evaluation system that synthesizes several phylogenetic and genomic analytical approaches. QS characterizes discordance in large-sparse and genome-wide data sets, overcoming issues of alignment sparsity and distinguishing strong conflict from weak support. We tested QS with simulations and recent plant phylogenies inferred from variously sized data sets. KEY RESULTS QS scores demonstrated convergence with increasing replicates and were not strongly affected by branch depth. Patterns of QS support from different phylogenies led to a coherent understanding of ancestral branches defining key disagreements, including the relationships of Ginkgo to cycads, magnoliids to monocots and eudicots, and mosses to liverworts. The relationships of ANA-grade angiosperms (Amborella, Nymphaeales, Austrobaileyales), major monocot groups, bryophytes, and fern families are likely highly discordant in their evolutionary histories, rather than poorly informed. QS can also detect discordance due to introgression in phylogenomic data. CONCLUSIONS Quartet Sampling is an efficient synthesis of phylogenetic tests that offers more comprehensive and specific information on branch support than conventional measures. The QS method corroborates growing evidence that phylogenomic investigations that incorporate discordance testing are warranted when reconstructing complex evolutionary histories, in particular those surrounding ANA-grade, monocots, and nonvascular plants.
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Affiliation(s)
- James B Pease
- Department of Biology, Wake Forest University, 455 Vine Street, Winston-Salem, North Carolina, 27101, USA
| | - Joseph W Brown
- Department of Ecology and Evolutionary Biology, University of Michigan, 830 North University, Ann Arbor, Michigan, 48109, USA
| | - Joseph F Walker
- Department of Ecology and Evolutionary Biology, University of Michigan, 830 North University, Ann Arbor, Michigan, 48109, USA
| | - Cody E Hinchliff
- Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, MS 3051, Moscow, Idaho, 83844, USA
| | - Stephen A Smith
- Department of Ecology and Evolutionary Biology, University of Michigan, 830 North University, Ann Arbor, Michigan, 48109, USA
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Hauser DA, Keuter A, McVay JD, Hipp AL, Manos PS. The evolution and diversification of the red oaks of the California Floristic Province (Quercus section Lobatae, series Agrifoliae). AMERICAN JOURNAL OF BOTANY 2017; 104:1581-1595. [PMID: 29885216 DOI: 10.3732/ajb.1700291] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 09/19/2017] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY The California Floristic Province (CA-FP) is a unique and diverse region of floral endemism, yet the timing and nature of divergence and diversification of many lineages remain underexplored. We seek to elucidate the evolutionary history of the red oaks of the CA-FP, the Agrifoliae. METHODS We collected PstI-associated RAD-seq data as well as morphometrics from individuals of the four species across their ranges, including varieties and hybrids. Phylogeny and divergence times were estimated. We analyzed morphological differentiation in over 70 plants using PCA and assessed species delimitation and admixture using genotype clustering analysis in over 40 plants. KEY RESULTS We find that the Agrifoliae are monophyletic and sister to all other red oak species. Within the Agrifoliae, all species are supported, with Quercus kelloggii sister to a clade of subevergreen taxa: (Quercus agrifolia - (Q. parvula + Q. wislizeni)). Molecular and morphometric analyses are equivocal for named varieties. Notably, Q. parvula var. tamalpaisensis appears to be part of a hybrid swarm between Q. parvula and Q. wislizeni. Dating estimates were concordant with previous hypotheses and geological evidence, with diversification occurring between 10 and 20 million years ago. CONCLUSIONS The Agrifoliae represent a geographically discrete, early-diverging red oak lineage that diversified during the period of drying and warming associated with Sierran uplift during the middle Miocene. Molecular differentiation within the clade supports the current taxonomy, including an east-west species level pattern (Q. parvula and Q. wislizeni) and north-south intraspecific patterns to some degree, although the latter require additional study.
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Affiliation(s)
- Duncan A Hauser
- Department of Biology, Duke University, Box 90338, Durham, North Carolina 27708 USA
| | - Al Keuter
- Kenneth S. Norris Center for Natural History, University of California Santa Cruz, 1156 High Street, Santa Cruz, California 95064 USA
| | - John D McVay
- Department of Biology, Duke University, Box 90338, Durham, North Carolina 27708 USA
| | - Andrew L Hipp
- The Morton Arboretum, 4100 Illinois Route 53, Lisle, Illinois 60532-1293 USA
| | - Paul S Manos
- Department of Biology, Duke University, Box 90338, Durham, North Carolina 27708 USA
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136
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Palacio-Lopez K, Keller SR, Molofsky J. Genomic Admixture Between Locally Adapted Populations of Arabidopsis thaliana (mouse ear cress): Evidence of Optimal Genetic Outcrossing Distance. J Hered 2017; 109:38-46. [DOI: 10.1093/jhered/esx079] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 09/16/2017] [Indexed: 11/14/2022] Open
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Dormontt EE, Prentis PJ, Gardner MG, Lowe AJ. Occasional hybridization between a native and invasive Senecio species in Australia is unlikely to contribute to invasive success. PeerJ 2017; 5:e3630. [PMID: 28828245 PMCID: PMC5562138 DOI: 10.7717/peerj.3630] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 07/11/2017] [Indexed: 11/29/2022] Open
Abstract
Background Hybridization between native and invasive species can facilitate introgression of native genes that increase invasive potential by providing exotic species with pre-adapted genes suitable for new environments. In this study we assessed the outcome of hybridization between native Senecio pinnatifolius var. pinnatifolius A.Rich. (dune ecotype) and invasive Senecio madagascariensis Poir. to investigate the potential for introgression of adaptive genes to have facilitated S. madagascariensis spread in Australia. Methods We used amplified fragment length polymorphisms (141 loci) and nuclear microsatellites (2 loci) to genotype a total of 118 adults and 223 seeds from S. pinnatifolius var.pinnatifolius and S. madagascariensis at one allopatric and two shared sites. We used model based clustering and assignment methods to establish whether hybrid seed set and mature hybrids occur in the field. Results We detected no adult hybrids in any population. Low incidence of hybrid seed set was found at Lennox Head where the contact zone overlapped for 20 m (6% and 22% of total seeds sampled for S. pinnatifolius var. pinnatifolius and S. madagascariensis respectively). One hybrid seed was detected at Ballina where a gap of approximately 150 m was present between species (2% of total seeds sampled for S. madagascariensis). Conclusions We found no evidence of adult hybrid plants at two shared sites. Hybrid seed set from both species was identified at low levels. Based on these findings we conclude that introgression of adaptive genes from S. pinnatifolius var. pinnatifolius is unlikely to have facilitated S. madagascariensis invasions in Australia. Revisitation of one site after two years could find no remaining S. pinnatifolius var. pinnatifolius, suggesting that contact zones between these species are dynamic and that S. pinnatifolius var. pinnatifolius may be at risk of displacement by S. madagascariensis in coastal areas.
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Affiliation(s)
- Eleanor E Dormontt
- The Environment Institute, School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Peter J Prentis
- Institute for Future Environments, School of Earth, Environmental and Biological Sciences, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Michael G Gardner
- School of Biological Sciences, Flinders University of South Australia, Adelaide, South Australia, Australia
| | - Andrew J Lowe
- The Environment Institute, School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
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138
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Wang C, Hu S, Gardner C, Lübberstedt T. Emerging Avenues for Utilization of Exotic Germplasm. TRENDS IN PLANT SCIENCE 2017; 22:624-637. [PMID: 28476651 DOI: 10.1016/j.tplants.2017.04.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 03/13/2017] [Accepted: 04/04/2017] [Indexed: 05/21/2023]
Abstract
Breeders have been successful in increasing crop performance by exploiting genetic diversity over time. However, the reported annual yield increases are not sufficient in view of rapid human population growth and global environmental changes. Exotic germplasm possesses high levels of genetic diversity for valuable traits. However, only a small fraction of naturally occurring genetic diversity is utilized. Moreover, the yield gap between elite and exotic germplasm widens, which increases the effort needed to use exotic germplasm and to identify beneficial alleles and for their introgression. The advent of high-throughput genotyping and phenotyping technologies together with emerging biotechnologies provide new opportunities to explore exotic genetic variation. This review will summarize potential challenges for utilization of exotic germplasm and provide solutions.
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Affiliation(s)
- Cuiling Wang
- Department of Agronomy, Henan University of Science and Technology, 263 Kaiyuan Avenue, Luoyang, Henan 471023, China; Department of Agronomy, Iowa State University,100 Osborn Drive, Ames, IA 50011, USA; State Key Laboratory of Wheat and Maize Crop Science, Henan Agricultural University, 95 Wenhua Road, Zhenzhou, Henan 450002, China
| | - Songlin Hu
- Department of Agronomy, Iowa State University,100 Osborn Drive, Ames, IA 50011, USA
| | - Candice Gardner
- Department of Agronomy, Iowa State University,100 Osborn Drive, Ames, IA 50011, USA; US Department of Agrigulture (USDA) Agricultural Research Service (ARS) Plant Introduction Research Unit, 100 Osborn Drive, Iowa State University, Ames, IA 50011, USA
| | - Thomas Lübberstedt
- Department of Agronomy, Iowa State University,100 Osborn Drive, Ames, IA 50011, USA.
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139
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Amasino RM, Cheung AY, Dresselhaus T, Kuhlemeier C. Focus on Flowering and Reproduction. PLANT PHYSIOLOGY 2017; 173:1-4. [PMID: 28049854 PMCID: PMC5210767 DOI: 10.1104/pp.16.01867] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Affiliation(s)
- Richard M Amasino
- Guest Editor
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706
| | - Alice Y Cheung
- Associate Editor
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, Massachusetts 01003
| | - Thomas Dresselhaus
- Guest Editor
- Cell Biology and Plant Biochemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Cris Kuhlemeier
- Monitoring Editor
- Institute of Plant Sciences, University of Bern, 3013 Bern, Switzerland
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140
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Zou P, Ng WL, Wu W, Dai S, Ning Z, Wang S, Liu Y, Fan Q, Zhou R. Similar Morphologies but Different Origins: Hybrid Status of Two More Semi-creeping Taxa of Melastoma. FRONTIERS IN PLANT SCIENCE 2017; 8:673. [PMID: 28491079 PMCID: PMC5405130 DOI: 10.3389/fpls.2017.00673] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 04/12/2017] [Indexed: 05/12/2023]
Abstract
Inferring the origins of hybrid taxa based on morphology alone is difficult because morphologically similar hybrids can arise from hybridization between different populations of the same parental species or be produced by hybridization of different parental species. In this study, we investigated the origins of two semi-creeping taxa in Melastoma, which are morphologically similar to a natural hybrid, M. intermedium, by sequencing a chloroplast intergenic spacer, nuclear ribosomal internal transcribed spacer and two low-copy nuclear genes (tpi and cam) in these taxa and their putative parental species. Our sequence analysis provides compelling evidence for the hybrid status of the two semi-creeping taxa: one originating from hybridization between M. dodecandrum and M. malabathricum, and the other between M. dodecandrum and M. normale. The origins of these hybrids are therefore clearly different from M. intermedium, and morphological similarity for the three hybrids is most likely due to their origins from hybridization between the same creeping species M. dodecandrum and a different erect species in each of the three cases. We also observed low rate of introgression from M. normale to M. dodecandrum, and genetic exchange between them may transfer adaptive traits to M. dodecandrum. Rare occurrence of these two hybrids may be due to small range overlaps between parental species in one case, and different flowering periods between parental species in the other.
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Affiliation(s)
- Peishan Zou
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen UniversityGuangzhou, China
| | - Wei Lun Ng
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen UniversityGuangzhou, China
| | - Wei Wu
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen UniversityGuangzhou, China
| | - Seping Dai
- Guangzhou Institute of Forestry and Landscape ArchitectureGuangzhou, China
| | - Zulin Ning
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of SciencesGuangzhou, China
| | - Shuqiong Wang
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen UniversityGuangzhou, China
| | - Ying Liu
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen UniversityGuangzhou, China
| | - Qiang Fan
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen UniversityGuangzhou, China
| | - Renchao Zhou
- State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen UniversityGuangzhou, China
- *Correspondence: Renchao Zhou,
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