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Abraham N, Chitrampalam P, Nelson B, Sharma Poudel R, Chittem K, Borowicz P, Brueggeman R, Jain S, LeBoldus JM. Microscopic, Biochemical, and Molecular Comparisons of Moderately Resistant and Susceptible Populus Genotypes Inoculated with Sphaerulina musiva. PHYTOPATHOLOGY 2019; 109:2074-2086. [PMID: 31483223 DOI: 10.1094/phyto-03-19-0105-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Sphaerulina musiva, the causal agent of Septoria leaf spot and stem canker, is responsible for mortality and yield loss in Populus plantations. However, little is known about the mode of infection and the mechanisms of resistance in this pathosystem. To characterize these phenomena, microscopic, biochemical, and transcriptome comparisons were performed between leaves of moderately resistant and susceptible genotypes of Populus inoculated with S. musiva conidia. Using scanning electron, cryofracture, and laser-scanning confocal microscopy, the infection and colonization of Populus leaves by S. musiva were examined across five time points (48 h, 96 h, 1 week, 2 weeks, and 3 weeks). The infection process was similar regardless of the host genotype. Differences in host colonization between susceptible and moderately resistant genotypes were apparent by 1 week postinoculation. However, the germination of conidia was greater on the susceptible than on the moderately resistant genotype (P < 0.008). Diaminobenzidine staining, a measure of hydrogen peroxide accumulation, was different (P < 0.001) between the host genotypes by 2 weeks postinoculation. Transcriptome differences between genotypes indicated that the speed and amplitude of the defense response were faster and more extensive in the moderately resistant genotype. Changes in gene expression support the microscopic and biochemical observations.
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Affiliation(s)
- Nivi Abraham
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108
| | | | - Berlin Nelson
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108
| | | | - Kishore Chittem
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108
| | - Pawel Borowicz
- Department of Animal Science, North Dakota State University, Fargo, ND 58105
| | - Robert Brueggeman
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108
| | - Shalu Jain
- Department of Plant Pathology, North Dakota State University, Fargo, ND 58108
| | - Jared Michael LeBoldus
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331
- Department of Forest Engineering Resources and Management, Oregon State University, Corvallis, OR 97331
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Wang D, Wang Z, Kang X, Zhang J. Genetic analysis of admixture and hybrid patterns of Populus hopeiensis and P. tomentosa. Sci Rep 2019; 9:4821. [PMID: 30886279 PMCID: PMC6423230 DOI: 10.1038/s41598-019-41320-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 03/06/2019] [Indexed: 12/25/2022] Open
Abstract
Hybridization and introgression have resulted in reticulate evolution within the genus Populus. Consequently, the origin and evolutionary history of some hybrids has become blurred. P. hopeiensis and P. tomentosa are endemic to China, and there is still controversy about their origin. We employ phylogeny, Bayesian estimation of admixture, and approximate Bayesian computation to investigate their origin with 10 nuclear DNA and 6 cpDNA regions. The combined evidences firmly support the hypothesis that they are hybrids and dominated by F1s. P. hopeiensis was generated via hybridization between the paternal species P. alba and maternal species P. davidiana. Surprisingly, P. tomentosa was divided into two genetic types with different maternal parents. P. adenopoda hybridized with P. alba directly to generate the first genetic type (mb1) and hybridized with P. davidiana followed by P. alba to generate the second (mb2). In both genetic types, P. alba acted as the male parent. The maternal parent was P. adenopoda and P. davidiana for mb1 and mb2, respectively. Hybridization not only generated these hybrids but also resulted in a unidirectional gene flow from P. davidiana to P. adenopoda. The Populus species have maintained a delicate balance between their genetic integrity and gene exchange.
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Affiliation(s)
- Dongsheng Wang
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China
- College of Horticulture Sciences & Technology, Hebei Normal University of Science & Technology, 066004, Qinhuangdao, China
| | - Zhaoshan Wang
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China.
- Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, China.
| | - Xiangyang Kang
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100091, China
| | - Jianguo Zhang
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, 100091, China.
- Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, China.
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Zeng YF, Zhang JG, Duan AG, Abuduhamiti B. Genetic structure of Populus hybrid zone along the Irtysh River provides insight into plastid-nuclear incompatibility. Sci Rep 2016; 6:28043. [PMID: 27306416 PMCID: PMC4910079 DOI: 10.1038/srep28043] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Accepted: 05/25/2016] [Indexed: 12/13/2022] Open
Abstract
In plants, the maintenance of species integrity despite hybridization has often been explained by the co-adaption of nuclear gene complexes. However, the interaction between plastid and nuclear sub-genomes has been underestimated. Here, we analyzed the genetic structure of a Populus alba and P. tremula hybrid zone along the Irtysh River system in the Altai region, northwest China, using both nuclear microsatellites and plastid DNA sequences. We found high interspecific differentiation, although the hybrid P. × canescens was prevalent. Bayesian inference classified most hybrids into F1, followed by a few back-crosses to P. alba, and fewer F2 hybrids and back-crosses to P. tremula, indicating a few introgressions but preference toward P. alba. When plastid haplotypes in parental species were distinct, P. × canescens carried the haplotypes of both parents, but showed significant linkage between intraspecific haplotype and nuclear genotypes at several microsatellite loci. Selection, rather than migration and assortative mating, might have contributed to such plastid-nuclear disequilibria. By removing later-generated hybrids carrying interspecific combinations of haplotype and nuclear genotypes, plastid-nuclear incompatibility has greatly limited the gene exchange between P. alba and P. tremula via backcrossing with hybrids, demonstrating a significant association between plastid haplotype and the proportion of nuclear admixture.
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Affiliation(s)
- Yan-Fei Zeng
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation, State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Jian-Guo Zhang
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation, State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China.,Collaborative Innovation Center of Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
| | - Ai-Guo Duan
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation, State Forestry Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
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Feng J, Jiang D, Shang H, Dong M, Wang G, He X, Zhao C, Mao K. Barcoding poplars (Populus L.) from western China. PLoS One 2013; 8:e71710. [PMID: 23977122 PMCID: PMC3747233 DOI: 10.1371/journal.pone.0071710] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 07/01/2013] [Indexed: 01/23/2023] Open
Abstract
Background Populus is an ecologically and economically important genus of trees, but distinguishing between wild species is relatively difficult due to extensive interspecific hybridization and introgression, and the high level of intraspecific morphological variation. The DNA barcoding approach is a potential solution to this problem. Methodology/Principal Findings Here, we tested the discrimination power of five chloroplast barcodes and one nuclear barcode (ITS) among 95 trees that represent 21 Populus species from western China. Among all single barcode candidates, the discrimination power is highest for the nuclear ITS, progressively lower for chloroplast barcodes matK (M), trnG-psbK (G) and psbK-psbI (P), and trnH-psbA (H) and rbcL (R); the discrimination efficiency of the nuclear ITS (I) is also higher than any two-, three-, or even the five-locus combination of chloroplast barcodes. Among the five combinations of a single chloroplast barcode plus the nuclear ITS, H+I and P+I differentiated the highest and lowest portion of species, respectively. The highest discrimination rate for the barcodes or barcode combinations examined here is 55.0% (H+I), and usually discrimination failures occurred among species from sympatric or parapatric areas. Conclusions/Significance In this case study, we showed that when discriminating Populus species from western China, the nuclear ITS region represents a more promising barcode than any maternally inherited chloroplast region or combination of chloroplast regions. Meanwhile, combining the ITS region with chloroplast regions may improve the barcoding success rate and assist in detecting recent interspecific hybridizations. Failure to discriminate among several groups of Populus species from sympatric or parapatric areas may have been the result of incomplete lineage sorting, frequent interspecific hybridizations and introgressions. We agree with a previous proposal for constructing a tiered barcoding system in plants, especially for taxonomic groups that have complex evolutionary histories (e.g. Populus).
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Affiliation(s)
- Jianju Feng
- School of Earth and Environmental Sciences & State Key Laboratory of Grassland Agro-Ecosystem, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, People’s Republic of China
- College of Plant Sciences, Xinjiang Production & Construction Corps Key Laboratory of Protection and Utilization of Biological Resources in Tarim Basin, Tarimu University, Alar, Xinjiang, People’s Republic of China
| | - Dechun Jiang
- School of Earth and Environmental Sciences & State Key Laboratory of Grassland Agro-Ecosystem, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, People’s Republic of China
| | - Huiying Shang
- School of Earth and Environmental Sciences & State Key Laboratory of Grassland Agro-Ecosystem, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, People’s Republic of China
| | - Miao Dong
- School of Earth and Environmental Sciences & State Key Laboratory of Grassland Agro-Ecosystem, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, People’s Republic of China
| | - Gaini Wang
- School of Earth and Environmental Sciences & State Key Laboratory of Grassland Agro-Ecosystem, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, People’s Republic of China
| | - Xinyu He
- School of Earth and Environmental Sciences & State Key Laboratory of Grassland Agro-Ecosystem, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, People’s Republic of China
| | - Changming Zhao
- School of Earth and Environmental Sciences & State Key Laboratory of Grassland Agro-Ecosystem, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, People’s Republic of China
| | - Kangshan Mao
- School of Earth and Environmental Sciences & State Key Laboratory of Grassland Agro-Ecosystem, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, People’s Republic of China
- * E-mail:
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Wullschleger SD, Weston DJ, DiFazio SP, Tuskan GA. Revisiting the sequencing of the first tree genome: Populus trichocarpa. TREE PHYSIOLOGY 2013; 33:357-364. [PMID: 23100257 DOI: 10.1093/treephys/tps081] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Ten years ago, it was announced that the Joint Genome Institute with funds provided by the Department of Energy, Office of Science, Biological and Environmental Research would sequence the black cottonwood (Populus trichocarpa Torr. & Gray) genome. This landmark decision was the culmination of work by the forest science community to develop Populus as a model system. Since its public release in late 2006, the availability of the Populus genome has spawned research in plant biology, morphology, genetics and ecology. Here we address how the tree physiologist has used this resource. More specifically, we revisit our earlier contention that the rewards of sequencing the Populus genome would depend on how quickly scientists working with woody perennials could adopt molecular approaches to investigate the mechanistic underpinnings of basic physiological processes. Several examples illustrate the integration of functional and comparative genomics into the forest sciences, especially in areas that target improved understanding of the developmental differences between woody perennials and herbaceous annuals (e.g., phase transitions). Sequencing the Populus genome and the availability of genetic and genomic resources has also been instrumental in identifying candidate genes that underlie physiological and morphological traits of interest. Genome-enabled research has advanced our understanding of how phenotype and genotype are related and provided insights into the genetic mechanisms whereby woody perennials adapt to environmental stress. In the future, we anticipate that low-cost, high-throughput sequencing will continue to facilitate research in tree physiology and enhance our understanding at scales of individual organisms and populations. A challenge remains, however, as to how genomic resources, including the Populus genome, can be used to understand ecosystem function. Although examples are limited, progress in this area is encouraging and will undoubtedly improve as future research targets the many unique aspects of Populus as a keystone species in terrestrial ecosystems.
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Affiliation(s)
- Stan D Wullschleger
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6301, USA.
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