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Mazer SJ, Hunter DJ, Hove AA, Dudley LS. Context-dependent concordance between physiological divergence and phenotypic selection in sister taxa with contrasting phenology and mating systems. AMERICAN JOURNAL OF BOTANY 2022; 109:1757-1779. [PMID: 35652277 DOI: 10.1002/ajb2.16016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 05/08/2022] [Accepted: 05/09/2022] [Indexed: 06/15/2023]
Abstract
PREMISE The study of phenotypic divergence of, and selection on, functional traits in closely related taxa provides the opportunity to detect the role of natural selection in driving diversification. If the strength or direction of selection in field populations differs between taxa in a pattern that is consistent with the phenotypic difference between them, then natural selection reinforces the divergence. Few studies have sought evidence for such concordance for physiological traits. METHODS Herbarium specimen records were used to detect phenological differences between sister taxa independent of the effects on flowering time of long-term variation in the climate across collection sites. In the field, physiological divergence in photosynthetic rate, transpiration rate, and instantaneous water-use efficiency were recorded during vegetative growth and flowering in 13 field populations of two taxon pairs of Clarkia, each comprising a self-pollinating and a outcrossing taxon. RESULTS Historically, each selfing taxon flowered earlier than its outcrossing sister taxon, independent of the effects of local long-term climatic conditions. Sister taxa differed in all focal traits, but the degree and (in one case) the direction of divergence depended on life stage. In general, self-pollinating taxa had higher gas exchange rates, consistent with their earlier maturation. In 6 of 18 comparisons, patterns of selection were concordant with the phenotypic divergence (or lack thereof) between sister taxa. CONCLUSIONS Patterns of selection on physiological traits measured in heterogeneous conditions do not reliably reflect divergence between sister taxa, underscoring the need for replicated studies of the direction of selection within and among taxa.
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Affiliation(s)
- Susan J Mazer
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA, 93106, USA
| | - David J Hunter
- Department of Mathematics and Computer Science, Westmont College, Santa Barbara, CA, 93108
| | - Alisa A Hove
- Biology Department, Warren Wilson College, P.O. Box 9000, Asheville, NC, 28815, USA
| | - Leah S Dudley
- Department of Biological and Environmental Sciences, East Central University, Ada, OK, 74820, USA
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Yang W, Cao J, Wu Y, Kong F, Li L. Review on plant terpenoid emissions worldwide and in China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 787:147454. [PMID: 34000546 DOI: 10.1016/j.scitotenv.2021.147454] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 04/26/2021] [Accepted: 04/26/2021] [Indexed: 05/21/2023]
Abstract
Biogenic volatile organic compounds (BVOCs), particularly terpenoids, can significantly drive the formation of ozone (O3) and secondary organic aerosols (SOA) in the atmosphere, as well as directly or indirectly affect global climate change. Understanding their emission mechanisms and the current progress in emission measurements and estimations are essential for the accurate determination of emission characteristics, as well as for evaluating their roles in atmospheric chemistry and climate change. This review summarizes the mechanisms of terpenoid synthesis and release, biotic and abiotic factors affecting their emissions, development of emission observation techniques, and emission estimations from hundreds of published papers. We provide a review of the main observations and estimations in China, which contributes a significant proportion to the total global BVOC emissions. The review suggests the need for further research on the comprehensive effects of environmental factors on terpenoid emissions, especially soil moisture and nitrogen content, which should be quantified in emission models to improve the accuracy of estimation. In China, it is necessary to conduct more accurate measurements for local plants in different regions using the dynamic enclosure technique to establish an accurate local emission rate database for dominant tree species. This will help improve the accuracy of both national and global emission inventories. This review provides a comprehensive understanding of terpenoid emissions as well as prospects for detailed research to accurately describe terpenoid emission characteristics worldwide and in China.
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Affiliation(s)
- Weizhen Yang
- College of Environmental Sciences and Engineering, Qingdao University, Qingdao 266071, China
| | - Jing Cao
- College of Environmental Sciences and Engineering, Qingdao University, Qingdao 266071, China
| | - Yan Wu
- School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China
| | - Fanlong Kong
- College of Environmental Sciences and Engineering, Qingdao University, Qingdao 266071, China.
| | - Lingyu Li
- College of Environmental Sciences and Engineering, Qingdao University, Qingdao 266071, China.
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Leaf isoprene emission as a trait that mediates the growth-defense tradeoff in the face of climate stress. Oecologia 2021; 197:885-902. [PMID: 33420520 DOI: 10.1007/s00442-020-04813-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 12/01/2020] [Indexed: 12/27/2022]
Abstract
Plant isoprene emissions are known to contribute to abiotic stress tolerance, especially during episodes of high temperature and drought, and during cellular oxidative stress. Recent studies have shown that genetic transformations to add or remove isoprene emissions cause a cascade of cellular modifications that include known signaling pathways, and interact to remodel adaptive growth-defense tradeoffs. The most compelling evidence for isoprene signaling is found in the shikimate and phenylpropanoid pathways, which produce salicylic acid, alkaloids, tannins, anthocyanins, flavonols and other flavonoids; all of which have roles in stress tolerance and plant defense. Isoprene also influences key gene expression patterns in the terpenoid biosynthetic pathways, and the jasmonic acid, gibberellic acid and cytokinin signaling networks that have important roles in controlling inducible defense responses and influencing plant growth and development, particularly following defoliation. In this synthesis paper, using past studies of transgenic poplar, tobacco and Arabidopsis, we present the evidence for isoprene acting as a metabolite that coordinates aspects of cellular signaling, resulting in enhanced chemical defense during periods of climate stress, while minimizing costs to growth. This perspective represents a major shift in our thinking away from direct effects of isoprene, for example, by changing membrane properties or quenching ROS, to indirect effects, through changes in gene expression and protein abundances. Recognition of isoprene's role in the growth-defense tradeoff provides new perspectives on evolution of the trait, its contribution to plant adaptation and resilience, and the ecological niches in which it is most effective.
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Zhao C, Guo H, Wang J, Wang Y, Zhang R. Melatonin Enhances Drought Tolerance by Regulating Leaf Stomatal Behavior, Carbon and Nitrogen Metabolism, and Related Gene Expression in Maize Plants. FRONTIERS IN PLANT SCIENCE 2021; 12:779382. [PMID: 34966404 PMCID: PMC8710518 DOI: 10.3389/fpls.2021.779382] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 11/15/2021] [Indexed: 05/07/2023]
Abstract
It is commonly known that exogenously applied melatonin can alleviate the impact of drought stress, but the mechanism used by melatonin to regulate stomatal behavior and carbon (C) and nitrogen (N) metabolism to increase drought resistance remains elusive. Herein, our aim was to investigate the influence of exogenous melatonin on the regulation of C and N metabolism in maize plants under water deficit. In this study, we analyzed stomatal behavior, the key components of C and N metabolism, and the gene expression and activity of enzymes involved in the C and N metabolism in maize plants. The results showed that the application of melatonin (100 μM) significantly increased maize growth and sustained the opening of stomata, and secondarily increased the photosynthetic capacity in maize. Under drought stress, foliar application of melatonin induced the gene transcription and activities of sucrose phosphate synthetase, ADP-glucose pyrophosphorylase, phosphoenolpyruvate carboxylase, and citrate synthase, resulting in the enhancement of sucrose and starch synthesis and the tricarboxylic acid (TCA) cycle. This enhancement in sugar biosynthesis and the TCA cycle might lead to stronger N assimilation. As anticipated, NO3 - reduction and NH4 + assimilation were also strengthened after melatonin treatment under drought stress. An increase was observed in some key enzymatic activities and transcription involved in nitrogen metabolism, such as that of nitrate reductase, nitrite reductase, glutamate synthase, and glutamine synthetase, in melatonin-treated, drought-stressed maize. Moreover, melatonin attenuated the drought-induced damage by reducing protein degradation and increasing the level of proline. Conclusively, our results indicate that exogenous melatonin enhances drought tolerance in maize via promoting stomatal opening and regulating C and N metabolism and related gene expression.
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Velikova V, Arena C, Izzo LG, Tsonev T, Koleva D, Tattini M, Roeva O, De Maio A, Loreto F. Functional and Structural Leaf Plasticity Determine Photosynthetic Performances during Drought Stress and Recovery in Two Platanus orientalis Populations from Contrasting Habitats. Int J Mol Sci 2020; 21:E3912. [PMID: 32486179 PMCID: PMC7312932 DOI: 10.3390/ijms21113912] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/23/2020] [Accepted: 05/28/2020] [Indexed: 11/25/2022] Open
Abstract
In the context of climatic change, more severe and long-lasting droughts will modify the fitness of plants, with potentially worse consequences on the relict trees. We have investigated the leaf phenotypic (anatomical, physiological and biochemical) plasticity in well-watered, drought-stressed and re-watered plants of two populations of Platanus orientalis, an endangered species in the west of the Mediterranean area. The two populations originated in contrasting climate (drier and warmer, Italy (IT) population; more humid and colder, Bulgaria (BG) population). The IT control plants had thicker leaves, enabling them to maintain higher leaf water content in the dry environment, and more spongy parenchyma, which could improve water conductivity of these plants and may result in easier CO2 diffusion than in BG plants. Control BG plants were also characterized by higher photorespiration and leaf antioxidants compared to IT plants. BG plants responded to drought with greater leaf thickness shrinkage. Drought also caused substantial reduction in photosynthetic parameters of both IT and BG plants. After re-watering, photosynthesis did not fully recover in either of the two populations. However, IT leaves became thicker, while photorespiration in BG plants further increased, perhaps indicating sustained activation of defensive mechanisms. Overall, our hypothesis, that plants with a fragmented habitat (i.e., the IT population) lose phenotypic plasticity but acquire traits allowing better resistance to the climate where they became adapted, remains confirmed.
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Affiliation(s)
- Violeta Velikova
- Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. bl. 21, Sofia 1113, Bulgaria
| | - Carmen Arena
- Department of Biology, University of Naples Federico II, Via Cinthia, 80126 Naples, Italy; (C.A.); (A.D.M.)
| | - Luigi Gennaro Izzo
- Department of Agricultural Sciences, University of Naples Federico II, Via Università 100, 80055 Portici, Italy;
| | - Tsonko Tsonev
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl. 21, Sofia 1113, Bulgaria; (T.T.); (O.R.)
| | | | - Massimiliano Tattini
- Institute for Sustainable Plant Protection, Department of Biology, Agriculture and Food Sciences, The National Research Council of Italy (CNR), I-50019 Sesto Fiorentino (Florence), Italy;
| | - Olympia Roeva
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl. 21, Sofia 1113, Bulgaria; (T.T.); (O.R.)
| | - Anna De Maio
- Department of Biology, University of Naples Federico II, Via Cinthia, 80126 Naples, Italy; (C.A.); (A.D.M.)
| | - Francesco Loreto
- Department of Biology, Agriculture and Food Sciences, The National Research Council of Italy (CNR), 00185 Rome, Italy
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