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Weng X, Haque T, Zhang L, Razzaque S, Lovell JT, Palacio-Mejía JD, Duberney P, Lloyd-Reilley J, Bonnette J, Juenger TE. A Pleiotropic Flowering Time QTL Exhibits Gene-by-Environment Interaction for Fitness in a Perennial Grass. Mol Biol Evol 2022; 39:6712601. [PMID: 36149808 PMCID: PMC9550986 DOI: 10.1093/molbev/msac203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Appropriate flowering time is a crucial adaptation impacting fitness in natural plant populations. Although the genetic basis of flowering variation has been extensively studied, its mechanisms in nonmodel organisms and its adaptive value in the field are still poorly understood. Here, we report new insights into the genetic basis of flowering time and its effect on fitness in Panicum hallii, a native perennial grass. Genetic mapping in populations derived from inland and coastal ecotypes identified flowering time quantitative trait loci (QTL) and many exhibited extensive QTL-by-environment interactions. Patterns of segregation within recombinant hybrids provide strong support for directional selection driving ecotypic divergence in flowering time. A major QTL on chromosome 5 (q-FT5) was detected in all experiments. Fine-mapping and expression studies identified a gene with orthology to a rice FLOWERING LOCUS T-like 9 (PhFTL9) as the candidate underlying q-FT5. We used a reciprocal transplant experiment to test for local adaptation and the specific impact of q-FT5 on performance. We did not observe local adaptation in terms of fitness tradeoffs when contrasting ecotypes in home versus away habitats. However, we observed that the coastal allele of q-FT5 conferred a fitness advantage only in its local habitat but not at the inland site. Sequence analyses identified an excess of low-frequency polymorphisms at the PhFTL9 promoter in the inland lineage, suggesting a role for either selection or population expansion on promoter evolution. Together, our findings demonstrate the genetic basis of flowering variation in a perennial grass and provide evidence for conditional neutrality underlying flowering time divergence.
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Affiliation(s)
| | - Taslima Haque
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | - Li Zhang
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | - Samsad Razzaque
- Present address: Plant Molecular and Cellular Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA
| | - John T Lovell
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, USA
| | - Juan Diego Palacio-Mejía
- Corporación Colombiana de Investigación Agropecuaria – AGROSAVIA, Centro de Investigación Tibaitatá. Kilómetro 14 vía Mosquera-Bogotá, Mosquera. Código postal 250047, Colombia
| | - Perla Duberney
- Kika de la Garza Plant Materials Center, USDA-NRCS, Kingsville, TX, USA
| | | | - Jason Bonnette
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
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VanWallendael A, Bonnette J, Juenger TE, Fritschi FB, Fay PA, Mitchell RB, Lloyd-Reilley J, Rouquette FM, Bergstrom GC, Lowry DB. Geographic variation in the genetic basis of resistance to leaf rust between locally adapted ecotypes of the biofuel crop switchgrass (Panicum virgatum). New Phytol 2020; 227:1696-1708. [PMID: 32202657 DOI: 10.1111/nph.16555] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 03/06/2020] [Indexed: 05/28/2023]
Abstract
Local adaptation is an important process in plant evolution, which can be impacted by differential pathogen pressures along environmental gradients. However, the degree to which pathogen resistance loci vary in effect across space and time is incompletely described. To understand how the genetic architecture of resistance varies across time and geographic space, we quantified rust (Puccinia spp.) severity in switchgrass (Panicum virgatum) plantings at eight locations across the central USA for 3 yr and conducted quantitative trait locus (QTL) mapping for rust progression. We mapped several variable QTLs, but two large-effect QTLs which we have named Prr1 and Prr2 were consistently associated with rust severity in multiple sites and years, particularly in northern sites. By contrast, there were numerous small-effect QTLs at southern sites, indicating a genotype-by-environment interaction in rust resistance loci. Interestingly, Prr1 and Prr2 had a strong epistatic interaction, which also varied in the strength and direction of effect across space. Our results suggest that abiotic factors covarying with latitude interact with the genetic loci underlying plant resistance to control rust infection severity. Furthermore, our results indicate that segregating genetic variation in epistatically interacting loci may play a key role in determining response to infection across geographic space.
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Affiliation(s)
- Acer VanWallendael
- Department of Plant Biology, Michigan State University, East Lansing, MI, 48824, USA
- Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, 48824, USA
- Department of Ecology, Evolutionary Biology, and Behavior, Michigan State University, East Lansing, MI, 48824, USA
- Plant Resilience Institute, Michigan State University, East Lansing, MI, 48824, USA
| | - Jason Bonnette
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, 78712, USA
| | - Thomas E Juenger
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, 78712, USA
| | - Felix B Fritschi
- Division of Plant Sciences, University of Missouri, Columbia, MO, 65201, USA
| | - Philip A Fay
- Soil and Water Research Laboratory, USDA-ARS Grassland, Temple, TX, 76508, USA
| | - Robert B Mitchell
- USDA-ARS Wheat, Sorghum, and Forage Research Unit, University of Nebraska, Lincoln, NE, 68588, USA
| | - John Lloyd-Reilley
- USDA-NRCS, Kika de la Garza Plant Materials Center, Kingsville, TX, 78572, USA
| | - Francis M Rouquette
- Texas A&M AgriLife Research, Texas A&M AgriLife Research and Extension Center, Overton, TX, 75684, USA
| | - Gary C Bergstrom
- School of Integrative Plant Science, Cornell University, Ithaca, NY, 14850, USA
| | - David B Lowry
- Department of Plant Biology, Michigan State University, East Lansing, MI, 48824, USA
- Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, 48824, USA
- Department of Ecology, Evolutionary Biology, and Behavior, Michigan State University, East Lansing, MI, 48824, USA
- Plant Resilience Institute, Michigan State University, East Lansing, MI, 48824, USA
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