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Hernández F, Vercellino RB, Fanna I, Presotto A. Maternal control of early life history traits affects overwinter survival and seedling phenotypes in sunflower (Helianthus annuus L.). PLANT BIOLOGY (STUTTGART, GERMANY) 2021; 23:307-316. [PMID: 33222359 DOI: 10.1111/plb.13220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 11/07/2020] [Indexed: 06/11/2023]
Abstract
When cultivated and wild plants hybridize, hybrids often show intermediate phenotypic traits relative to their parents, which makes them unfit in natural environments. However, maternal genetic effects may affect the outcome of hybridization by controlling expression of the earliest life history traits. Here, using wild, cultivated and reciprocal crop-wild sunflower (Helianthus annuus L.) hybrids, we evaluated the maternal effects on emergence timing and seedling establishment in the field and on seedling traits under controlled conditions. In the field, we evaluated reciprocal crop-wild hybrids between two wild populations with contrasting dormancy (the high dormant BAR and the low dormant DIA) and one cultivar (CROP) with low dormancy. Under controlled conditions, we evaluated reciprocal crop-wild hybrids between two wild populations (BAR and RCU) and one CROP under three contrasting temperature treatments. In the field, BAR overwintered as dormant seeds whereas DIA and CROP showed high autumn emergence (~50% of planted seeds), resulting in differential overwinter survival and seedling establishment in the spring. Reciprocal crop-wild hybrids resembled their female parents in emergence timing and success of seedling establishment. Under controlled conditions, we observed large maternal effects on most seedling traits across temperatures. Cotyledon size explained most of the variation in seedling traits, suggesting that the maternal effects on seed size have cascading effects on seedling traits. Maternal effects on early life history traits affect early plant survival and phenotypic variation of crop-wild hybrids, thus, they should be addressed in hybridization studies, especially those involving highly divergent parents, such as cultivated species and their wild ancestors.
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Affiliation(s)
- F Hernández
- CERZOS, Dpto. Agronomía, Universidad Nacional del Sur (UNS)-CONICET, San Andrés 800, CP, 8000, Bahía Blanca, Argentina
| | - R B Vercellino
- CERZOS, Dpto. Agronomía, Universidad Nacional del Sur (UNS)-CONICET, San Andrés 800, CP, 8000, Bahía Blanca, Argentina
| | - I Fanna
- CERZOS, Dpto. Agronomía, Universidad Nacional del Sur (UNS)-CONICET, San Andrés 800, CP, 8000, Bahía Blanca, Argentina
| | - A Presotto
- CERZOS, Dpto. Agronomía, Universidad Nacional del Sur (UNS)-CONICET, San Andrés 800, CP, 8000, Bahía Blanca, Argentina
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Bernau VM, Jardón Barbolla L, McHale LK, Mercer KL. Germination response of diverse wild and landrace chile peppers (Capsicum spp.) under drought stress simulated with polyethylene glycol. PLoS One 2020; 15:e0236001. [PMID: 33196641 PMCID: PMC7668591 DOI: 10.1371/journal.pone.0236001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 10/10/2020] [Indexed: 11/19/2022] Open
Abstract
Responses to drought within a single species may vary based on plant developmental stage, drought severity, and the avoidance or tolerance mechanisms employed. Early drought stress can restrict emergence and seedling growth. Thus, in areas where water availability is limited, rapid germination leading to early plant establishment may be beneficial. Alternatively, germination without sufficient water to support the seedling may lead to early senescence, so reduced germination under low moisture conditions may be adaptive at the level of the population. We studied the germination response to osmotic stress of diverse chile pepper germplasm collected in southern Mexico from varied ecozones, cultivation systems, and of named landraces. Drought stress was simulated using polyethylene glycol solutions. Overall, survival time analysis revealed delayed germination at the 20% concentration of PEG across all ecozones. The effect was most pronounced in the genotypes from hotter, drier ecozones. Additionally, accessions from wetter and cooler ecozones had the fastest rate of germination. Moreover, accessions of the landraces Costeño Rojo and Tusta germinated more slowly and incompletely if sourced from a drier ecozone than a wetter one, indicating that slower, reduced germination under drought stress may be an adaptive avoidance mechanism. Significant differences were also observed between named landraces, with more domesticated types from intensive cultivation systems nearly always germinating faster than small-fruited backyard- or wild-types, perhaps due to the fact that the smaller-fruited accessions may have undergone less selection. Thus, we conclude that there is evidence of local adaptation to both ecozone of origin and source cultivation system in germination characteristics of diverse chile peppers.
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Affiliation(s)
- Vivian M. Bernau
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, Ohio, United States of America
| | - Lev Jardón Barbolla
- Centro de Investigaciones Interdisciplinarias en Ciencias y Humanidades, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Leah K. McHale
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, Ohio, United States of America
| | - Kristin L. Mercer
- Department of Horticulture and Crop Science, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
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Reynolds HS, Wagner R, Wang G, Burrill HM, Bever JD, Alexander HM. Effects of the soil microbiome on the demography of two annual prairie plants. Ecol Evol 2020; 10:6208-6222. [PMID: 32724508 PMCID: PMC7381566 DOI: 10.1002/ece3.6341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 04/09/2020] [Accepted: 04/14/2020] [Indexed: 01/04/2023] Open
Abstract
Both mutualistic and pathogenic soil microbes are known to play important roles in shaping the fitness of plants, likely affecting plants at different life cycle stages.In order to investigate the differential effects of native soil mutualists and pathogens on plant fitness, we compared survival and reproduction of two annual tallgrass prairie plant species (Chamaecrista fasciculata and Coreopsis tinctoria) in a field study using 3 soil inocula treatments containing different compositions of microbes. The soil inocula types included fresh native whole soil taken from a remnant prairie containing both native mutualists and pathogens, soil enhanced with arbuscular mycorrhizal (AM) fungi derived from remnant prairies, and uninoculated controls.For both species, plants inoculated with native prairie AM fungi performed much better than those in uninoculated soil for all parts of the life cycle. Plants in the native whole prairie soil were either generally similar to plants in the uninoculated soil or had slightly higher survival or reproduction.Overall, these results suggest that native prairie AM fungi can have important positive effects on the fitness of early successional plants. As inclusion of prairie AM fungi and pathogens decreased plant fitness relative to prairie AM fungi alone, we expect that native pathogens also can have large effects on fitness of these annuals. Our findings support the use of AM fungi to enhance plant establishment in prairie restorations.
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Affiliation(s)
- Hannah S. Reynolds
- Department of Ecology & Evolutionary BiologyUniversity of KansasLawrenceKSUSA
| | - Rebekah Wagner
- Department of Ecology & Evolutionary BiologyUniversity of KansasLawrenceKSUSA
- Kansas Biological SurveyUniversity of KansasLawrenceKSUSA
| | - Guangzhou Wang
- Department of Ecology & Evolutionary BiologyUniversity of KansasLawrenceKSUSA
- Kansas Biological SurveyUniversity of KansasLawrenceKSUSA
| | - Haley M. Burrill
- Department of Ecology & Evolutionary BiologyUniversity of KansasLawrenceKSUSA
- Kansas Biological SurveyUniversity of KansasLawrenceKSUSA
| | - James D. Bever
- Department of Ecology & Evolutionary BiologyUniversity of KansasLawrenceKSUSA
- Kansas Biological SurveyUniversity of KansasLawrenceKSUSA
| | - Helen M. Alexander
- Department of Ecology & Evolutionary BiologyUniversity of KansasLawrenceKSUSA
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Pace BA, Alexander HM, Emry DJ, Mercer KL. Reliable Method for Assessing Seed Germination, Dormancy, and Mortality under Field Conditions. J Vis Exp 2016. [PMID: 27842344 DOI: 10.3791/54663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
We describe techniques for approximating seed bank dynamics over time using Helianthus annuus as an example study species. Strips of permeable polyester fabric and glue can be folded and glued to construct a strip of compartments that house seeds and identifying information, while allowing contact with soil leachate, water, microorganisms, and ambient temperature. Strips may be constructed with a wide range of compartment numbers and sizes and allow the researcher to house a variety of genotypes within a single species, different species, or seeds that have experienced different treatments. As opposed to individual seed packets, strips are more easily retrieved as a unit. While replicate packets can be included within a strip, different strips can act as blocks or can be retrieved at different times for observation of seed behavior over time. We used a high temperature glue gun to delineate compartments and sealed the strips once the seed and tags identifying block and removal times were inserted. The seed strips were then buried in the field at the desired depth, with the location marked for later removal. Burrowing animal predators were effectively excluded by use of a covering of metal mesh hardware cloth on the soil surface. After the selected time interval for burial, strips were dug up and seeds were assessed for germination, dormancy and mortality. While clearly dead seeds can often be distinguished from ungerminated living ones by eye, dormant seeds were conclusively identified using a standard Tetrazolium chloride colorimetric test for seed viability.
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Affiliation(s)
- Brian A Pace
- Department of Horticulture and Crop Science, Ohio State University;
| | - Helen M Alexander
- Department of Ecology and Evolutionary Biology, University of Kansas
| | | | - Kristin L Mercer
- Department of Horticulture and Crop Science, Ohio State University
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Moyers BT, Rieseberg LH. Remarkable life history polymorphism may be evolving under divergent selection in the silverleaf sunflower. Mol Ecol 2016; 25:3817-30. [DOI: 10.1111/mec.13723] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 06/01/2016] [Accepted: 06/02/2016] [Indexed: 01/27/2023]
Affiliation(s)
- Brook T. Moyers
- Department of Botany; University of British Columbia; 3529-6270 University Blvd Vancouver British Columbia Canada V6T 1Z4
| | - Loren H. Rieseberg
- Department of Botany; University of British Columbia; 3529-6270 University Blvd Vancouver British Columbia Canada V6T 1Z4
- Department of Biology; Indiana University; 1001 E 3rd St Bloomington IN 47405 USA
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Kost MA, Alexander HM, Jason Emry D, Mercer KL. Life history traits and phenotypic selection among sunflower crop-wild hybrids and their wild counterpart: implications for crop allele introgression. Evol Appl 2015; 8:510-24. [PMID: 26029263 PMCID: PMC4430773 DOI: 10.1111/eva.12261] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 03/18/2015] [Indexed: 12/01/2022] Open
Abstract
Hybridization produces strong evolutionary forces. In hybrid zones, selection can differentially occur on traits and selection intensities may differ among hybrid generations. Understanding these dynamics in crop-wild hybrid zones can clarify crop-like traits likely to introgress into wild populations and the particular hybrid generations through which introgression proceeds. In a field experiment with four crop-wild hybrid Helianthus annuus (sunflower) cross types, we measured growth and life history traits and performed phenotypic selection analysis on early season traits to ascertain the likelihood, and routes, of crop allele introgression into wild sunflower populations. All cross types overwintered, emerged in the spring, and survived until flowering, indicating no early life history barriers to crop allele introgression. While selection indirectly favored earlier seedling emergence and taller early season seedlings, direct selection only favored greater early season leaf length. Further, there was cross type variation in the intensity of selection operating on leaf length. Thus, introgression of multiple early season crop-like traits, due to direct selection for greater early season leaf length, should not be impeded by any cross type and may proceed at different rates among generations. In sum, alleles underlying early season sunflower crop-like traits are likely to introgress into wild sunflower populations.
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Affiliation(s)
- Matthew A Kost
- Department of Horticulture and Crop Science, The Ohio State UniversityWooster, OH, USA
| | - Helen M Alexander
- Department of Ecology and Evolutionary Biology, University of KansasLawrence, KS, USA
| | - D Jason Emry
- Department of Ecology and Evolutionary Biology, University of KansasLawrence, KS, USA
- Department of Biology, Washburn UniversityTopeka, KS, USA
| | - Kristin L Mercer
- Department of Horticulture and Crop Science, The Ohio State UniversityColumbus, OH, USA
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Pace BA, Alexander HM, Emry JD, Mercer KL. Seed fates in crop-wild hybrid sunflower: crop allele and maternal effects. Evol Appl 2015; 8:121-32. [PMID: 25685189 PMCID: PMC4319861 DOI: 10.1111/eva.12236] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 10/07/2014] [Indexed: 11/28/2022] Open
Abstract
Domestication has resulted in selection upon seed traits found in wild populations, yet crop-wild hybrids retain some aspects of both parental phenotypes. Seed fates of germination, dormancy, and mortality can influence the success of crop allele introgression in crop-wild hybrid zones, especially if crop alleles or crop-imparted seed coverings result in out-of-season germination. We performed a seed burial experiment using crop, wild, and diverse hybrid sunflower (Helianthus annuus) cross types to test how a cross type's maternal parent and nuclear genetic composition might affect its fate under field conditions. We observed higher maladaptive fall germination in the crop- and F1- produced seeds than wild-produced seeds and, due to an interaction with percent crop alleles, fall germination was higher for cross types with more crop-like nuclear genetics. By spring, crop-produced cross types had the highest overwintering mortality, primarily due to higher fall germination. Early spring germination was identical across maternal types, but germination continued for F1-produced seeds. In conclusion, the more wild-like the maternal parent or the less proportion of the cross type's genome contributed by the crop, the greater likelihood a seed will remain ungerminated than die. Wild-like dormancy may facilitate introgression through future recruitment from the soil seed bank.
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Affiliation(s)
- Brian A Pace
- Department of Horticulture and Crop Science, Ohio State University Columbus, OH, USA
| | - Helen M Alexander
- Department of Ecology and Evolutionary Biology, University of Kansas Lawrence, KS, USA
| | - Jason D Emry
- Department of Biology, Washburn University Topeka, KS, USA
| | - Kristin L Mercer
- Department of Horticulture and Crop Science, Ohio State University Columbus, OH, USA
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Mercer KL, Emry DJ, Snow AA, Kost MA, Pace BA, Alexander HM. Fitness of crop-wild hybrid sunflower under competitive conditions: implications for crop-to-wild introgression. PLoS One 2014; 9:e109001. [PMID: 25295859 PMCID: PMC4189920 DOI: 10.1371/journal.pone.0109001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 08/18/2014] [Indexed: 11/20/2022] Open
Abstract
Understanding the likelihood and extent of introgression of novel alleles in hybrid zones requires comparison of lifetime fitness of parents and hybrid progeny. However, fitness differences among cross types can vary depending on biotic conditions, thereby influencing introgression patterns. Based on past work, we predicted that increased competition would enhance introgression between cultivated and wild sunflower (Helianthus annuus) by reducing fitness advantages of wild plants. To test this prediction, we established a factorial field experiment in Kansas, USA where we monitored the fitness of four cross types (Wild, F1, F2, and BCw hybrids) under different levels of interspecific and intraspecific competition. Intraspecific manipulations consisted both of density of competitors and of frequency of crop-wild hybrids. We recorded emergence of overwintered seeds, survival to reproduction, and numbers of seeds produced per reproductive plant. We also calculated two compound fitness measures: seeds produced per emerged seedling and seeds produced per planted seed. Cross type and intraspecific competition affected emergence and survival to reproduction, respectively. Further, cross type interacted with competitive treatments to influence all other fitness traits. More intense competition treatments, especially related to density of intraspecific competitors, repeatedly reduced the fitness advantage of wild plants when considering seeds produced per reproductive plant and per emerged seedling, and F2 plants often became indistinguishable from the wilds. Wild fitness remained superior when seedling emergence was also considered as part of fitness, but the fitness of F2 hybrids relative to wild plants more than quadrupled with the addition of interspecific competitors and high densities of intraspecific competitors. Meanwhile, contrary to prediction, lower hybrid frequency reduced wild fitness advantage. These results emphasize the importance of taking a full life cycle perspective. Additionally, due to effects of exogenous selection, a given hybrid generation may be especially well-suited to hastening introgression under particular environmental conditions.
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Affiliation(s)
- Kristin L. Mercer
- Ohio State University, Department of Horticulture and Crop Science, Columbus, Ohio, United States of America
- * E-mail:
| | - D. Jason Emry
- University of Kansas, Department of Ecology and Evolutionary Biology, Lawrence, Kansas, United States of America
- Washburn University, Topeka, Kansas, United States of America
| | - Allison A. Snow
- Ohio State University, Department of Evolution, Ecology, and Organismal Biology, Columbus, Ohio, United States of America
| | - Matthew A. Kost
- Ohio State University, Department of Horticulture and Crop Science, Columbus, Ohio, United States of America
| | - Brian A. Pace
- Ohio State University, Department of Horticulture and Crop Science, Columbus, Ohio, United States of America
| | - Helen M. Alexander
- University of Kansas, Department of Ecology and Evolutionary Biology, Lawrence, Kansas, United States of America
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