1
|
Zhou H, Song X, Lu MZ. Growth-regulating factor 15-mediated vascular cambium differentiation positively regulates wood formation in hybrid poplar (Populus alba × P. glandulosa). Front Plant Sci 2024; 15:1343312. [PMID: 38425797 PMCID: PMC10902170 DOI: 10.3389/fpls.2024.1343312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 02/01/2024] [Indexed: 03/02/2024]
Abstract
Introduction Hybrid poplars are industrial trees in China. An understanding of the molecular mechanism underlying wood formation in hybrid poplars is necessary for molecular breeding. Although the division and differentiation of vascular cambial cells is important for secondary growth and wood formation, the regulation of this process is largely unclear. Methods In this study, mPagGRF15 OE and PagGRF15-SRDX transgenic poplars were generated to investigate the function of PagGRF15. RNA-seq and qRT-PCR were conducted to analyze genome-wide gene expression, while ChIP‒seq and ChIP-PCR were used to identified the downstream genes regulated by PagGRF15. Results and discussion We report that PagGRF15 from hybrid poplar (Populus alba × P. glandulosa), a growth-regulating factor, plays a critical role in the regulation of vascular cambium activity. PagGRF15 was expressed predominantly in the cambial zone of vascular tissue. Overexpression of mPagGRF15 (the mutated version of GRF15 in the miR396 target sequence) in Populus led to decreased plant height and internode number. Further stem cross sections showed that the mPagGRF15 OE plants exhibited significant changes in vascular pattern with an increase in xylem and a reduction in phloem. In addition, cambium cell files were decreased in the mPagGRF15 OE plants. However, dominant suppression of the downstream genes of PagGRF15 using PagGRF15-SRDX showed an opposite phenotype. Based on the RNA-seq and ChIP-seq results, combining qRT-PCR and ChIP-PCR analysis, candidate genes, such as WOX4b, PXY and GID1.3, were obtained and found to be mainly involved in cambial activity and xylem differentiation. Accordingly, we speculated that PagGRF15 functions as a positive regulator mediating xylem differentiation by repressing the expression of the WOX4a and PXY genes to set the pace of cambial activity. In contrast, PagGRF15 mediated the GA signaling pathway by upregulating GID1.3 expression to stimulate xylem differentiation. This study provides valuable information for further studies on vascular cambium differentiation mechanisms and genetic improvement of the specific gravity of wood in hybrid poplars.
Collapse
Affiliation(s)
- Houjun Zhou
- The Engineering Research Institute of Agriculture and Forestry, Ludong University, Yantai, China
| | - Xueqin Song
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Meng-Zhu Lu
- State Key Laboratory of Subtropical Silviculture, College of Forestry and Biotechnology, Zhejiang A&F University, Hangzhou, China
| |
Collapse
|
2
|
Zhang S, Cao L, Chang R, Zhang H, Yu J, Li C, Liu G, Yan J, Xu Z. Network Analysis of Metabolome and Transcriptome Revealed Regulation of Different Nitrogen Concentrations on Hybrid Poplar Cambium Development. Int J Mol Sci 2024; 25:1017. [PMID: 38256092 PMCID: PMC10816006 DOI: 10.3390/ijms25021017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/08/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024] Open
Abstract
Secondary development is a key biological characteristic of woody plants and the basis of wood formation. Exogenous nitrogen can affect the secondary growth of poplar, and some regulatory mechanisms have been found in the secondary xylem. However, the effect of nitrogen on cambium has not been reported. Herein, we investigated the effects of different nitrogen concentrations on cambium development using combined transcriptome and metabolome analysis. The results show that, compared with 1 mM NH4NO3 (M), the layers of hybrid poplar cambium cells decreased under the 0.15 mM NH4NO3 (L) and 0.3 mM NH4NO3 (LM) treatments. However, there was no difference in the layers of hybrid poplar cambium cells under the 3 mM NH4NO3 (HM) and 5 mM NH4NO3 (H) treatments. Totals of 2365, 824, 649 and 398 DEGs were identified in the M versus (vs.) L, M vs. LM, M vs. HM and M vs. H groups, respectively. Expression profile analysis of the DEGs showed that exogenous nitrogen affected the gene expression involved in plant hormone signal transduction, phenylpropanoid biosynthesis, the starch and sucrose metabolism pathway and the ubiquitin-mediated proteolysis pathway. In M vs. L, M vs. LM, M vs. HM and M vs. H, differential metabolites were enriched in flavonoids, lignans, coumarins and saccharides. The combined analysis of the transcriptome and metabolome showed that some genes and metabolites in plant hormone signal transduction, phenylpropanoid biosynthesis and starch and sucrose metabolism pathways may be involved in nitrogen regulation in cambium development, whose functions need to be verified. In this study, from the point of view that nitrogen influences cambium development to regulate wood formation, the network analysis of the transcriptome and metabolomics of cambium under different nitrogen supply levels was studied for the first time, revealing the potential regulatory and metabolic mechanisms involved in this process and providing new insights into the effects of nitrogen on wood development.
Collapse
Affiliation(s)
- Shuang Zhang
- College of Life Science, Northeast Forestry University, Harbin 150040, China; (S.Z.); (R.C.)
| | - Lina Cao
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China; (L.C.); (H.Z.); (J.Y.); (C.L.); (G.L.)
| | - Ruhui Chang
- College of Life Science, Northeast Forestry University, Harbin 150040, China; (S.Z.); (R.C.)
| | - Heng Zhang
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China; (L.C.); (H.Z.); (J.Y.); (C.L.); (G.L.)
| | - Jiajie Yu
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China; (L.C.); (H.Z.); (J.Y.); (C.L.); (G.L.)
| | - Chunming Li
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China; (L.C.); (H.Z.); (J.Y.); (C.L.); (G.L.)
| | - Guanjun Liu
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China; (L.C.); (H.Z.); (J.Y.); (C.L.); (G.L.)
| | - Junxin Yan
- College of Landscape Architecture, Northeast Forestry University, Harbin 150040, China
| | - Zhiru Xu
- College of Life Science, Northeast Forestry University, Harbin 150040, China; (S.Z.); (R.C.)
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China; (L.C.); (H.Z.); (J.Y.); (C.L.); (G.L.)
| |
Collapse
|
3
|
Robertson SM, Sakariyahu SK, Bolaji A, Belmonte MF, Wilkins O. Growth-limiting drought stress induces time-of-day-dependent transcriptome and physiological responses in hybrid poplar. AoB Plants 2022; 14:plac040. [PMID: 36196395 PMCID: PMC9521483 DOI: 10.1093/aobpla/plac040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 08/25/2022] [Indexed: 06/16/2023]
Abstract
Drought stress negatively impacts the health of long-lived trees. Understanding the genetic mechanisms that underpin response to drought stress is requisite for selecting or enhancing climate change resilience. We aimed to determine how hybrid poplars respond to prolonged and uniform exposure to drought; how responses to moderate and more severe growth-limiting drought stresses differed; and how drought responses change throughout the day. We established hybrid poplar trees (Populus × 'Okanese') from unrooted stem cutting with abundant soil moisture for 6 weeks. We then withheld water to establish well-watered, moderate and severe growth-limiting drought conditions. These conditions were maintained for 3 weeks during which growth was monitored. We then measured photosynthetic rates and transcriptomes of leaves that had developed during the drought treatments at two times of day. The moderate and severe drought treatments elicited distinct changes in growth and development, photosynthetic rates and global transcriptome profiles. Notably, the time of day of sampling produced the strongest effect in the transcriptome data. The moderate drought treatment elicited global transcriptome changes that were intermediate to the severe and well-watered treatments in the early evening but did not elicit a strong drought response in the morning. Stable drought conditions that are sufficient to limit plant growth elicit distinct transcriptional profiles depending on the degree of water limitation and on the time of day at which they are measured. There appears to be a limited number of genes and functional gene categories that are responsive to all of the tested drought conditions in this study emphasizing the complex nature of drought regulation in long-lived trees.
Collapse
Affiliation(s)
- Sean M Robertson
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | | | - Ayooluwa Bolaji
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB R3E 3R2, Canada
| | - Mark F Belmonte
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | | |
Collapse
|
4
|
Park SJ, Bae EK, Choi H, Yoon SK, Jang HA, Choi YI, Lee H. Knockdown of PagSAP11 Confers Drought Resistance and Promotes Lateral Shoot Growth in Hybrid Poplar (Populus alba × Populus tremula var. glandulosa). Front Plant Sci 2022; 13:925744. [PMID: 35812954 PMCID: PMC9263715 DOI: 10.3389/fpls.2022.925744] [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] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
Plants have evolved defense mechanisms to overcome unfavorable climatic conditions. The growth and development of plants are regulated in response to environmental stress. In this study, we investigated the molecular and physiological characteristics of a novel gene PagSAP11 in hybrid poplar (Populus alba × Populus tremula var. glandulosa) under drought stress. PagSAP11, a stress-associated protein (SAP) family gene, encodes a putative protein containing an A20 and AN1 zinc-finger domain at its N- and C-termini, respectively. Knockdown of PagSAP11 transgenic poplars (SAP11-Ri) enhanced their tolerance to drought stress compared with wild type plants. Moreover, the RNAi lines showed increased branching of lateral shoots that led to a gain in fresh weight, even when grown in the living modified organism (LMO) field. In SAP11-Ri transgenic plants, the expression levels of genes involved in axillary bud outgrowth and cell proliferation such as DML10, CYP707A and RAX were increased while the DRM gene which involved in bud dormancy was down-regulated. Taken together, these results indicate that PagSAP11 represents a promising candidate gene for engineering trees with improved stress tolerance and growth during unfavorable conditions.
Collapse
Affiliation(s)
- Su Jin Park
- Department of Forest Bioresources, National Institute of Forest Science, Suwon, South Korea
| | - Eun-Kyung Bae
- Department of Forest Bioresources, National Institute of Forest Science, Suwon, South Korea
| | - Hyunmo Choi
- Forest Biomaterials Research Center, National Institute of Forest Science, Jinju, South Korea
| | - Seo-Kyung Yoon
- Department of Forest Sciences, Seoul National University, Seoul, South Korea
| | - Hyun-A Jang
- Department of Forest Bioresources, National Institute of Forest Science, Suwon, South Korea
| | - Young-Im Choi
- National Forest Seed and Variety Center, Forest Service, Chungju, South Korea
| | - Hyoshin Lee
- Department of Forest Bioresources, National Institute of Forest Science, Suwon, South Korea
| |
Collapse
|
5
|
Ranjan A, Perrone I, Alallaq S, Singh R, Rigal A, Brunoni F, Chitarra W, Guinet F, Kohler A, Martin F, Street NR, Bhalerao R, Legué V, Bellini C. Molecular basis of differential adventitious rooting competence in poplar genotypes. J Exp Bot 2022; 73:4046-4064. [PMID: 35325111 PMCID: PMC9232201 DOI: 10.1093/jxb/erac126] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 03/23/2022] [Indexed: 06/14/2023]
Abstract
Recalcitrant adventitious root (AR) development is a major hurdle in propagating commercially important woody plants. Although significant progress has been made to identify genes involved in subsequent steps of AR development, the molecular basis of differences in apparent recalcitrance to form AR between easy-to-root and difficult-to-root genotypes remains unknown. To address this, we generated cambium tissue-specific transcriptomic data from stem cuttings of hybrid aspen, T89 (difficult-to-root) and hybrid poplar OP42 (easy-to-root), and used transgenic approaches to verify the role of several transcription factors in the control of adventitious rooting. Increased peroxidase activity was positively correlated with better rooting. We found differentially expressed genes encoding reactive oxygen species scavenging proteins to be enriched in OP42 compared with T89. A greater number of differentially expressed transcription factors in cambium cells of OP42 compared with T89 was revealed by a more intense transcriptional reprograming in the former. PtMYC2, a potential negative regulator, was less expressed in OP42 compared with T89. Using transgenic approaches, we demonstrated that PttARF17.1 and PttMYC2.1 negatively regulate adventitious rooting. Our results provide insights into the molecular basis of genotypic differences in AR and implicate differential expression of the master regulator MYC2 as a critical player in this process.
Collapse
Affiliation(s)
| | | | | | - Rajesh Singh
- Present address: Department of Biotechnology, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176061, India
| | - Adeline Rigal
- Université de Lorraine, INRAE, UMR Interactions Arbres/Microorganismes, Laboratory of Excellence ARBRE, INRAE GrandEst-Nancy, Champenoux, 54280France
| | - Federica Brunoni
- Present address: Laboratory of Growth Regulators, Faculty of Science, Palacký University & Institute of Experimental Botany, The Czech Academy of Sciences, Slechtitelu 27, CZ-78371, Olomouc, Czech Republic
| | - Walter Chitarra
- Institute for Sustainable Plant Protection, National Research Council of Italy (IPSP-CNR), I-10135 Torino, Italy
- Research Centre for Viticulture and Enology, Council for Agricultural Research and Economics (CREA-VE), I-31015 Conegliano (TV), Italy
| | - Frederic Guinet
- Université de Lorraine, INRAE, UMR Interactions Arbres/Microorganismes, Laboratory of Excellence ARBRE, INRAE GrandEst-Nancy, Champenoux, 54280France
| | - Annegret Kohler
- Université de Lorraine, INRAE, UMR Interactions Arbres/Microorganismes, Laboratory of Excellence ARBRE, INRAE GrandEst-Nancy, Champenoux, 54280France
| | - Francis Martin
- Université de Lorraine, INRAE, UMR Interactions Arbres/Microorganismes, Laboratory of Excellence ARBRE, INRAE GrandEst-Nancy, Champenoux, 54280France
| | - Nathaniel R Street
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, SE-90736 Umeå, Sweden
| | - Rishikesh Bhalerao
- Umeå Plant Science Centre, Department of Forest Genetics and Physiology, Swedish Agricultural University, SE-90183 Umeå, Sweden
| | - Valérie Legué
- Present address: Université Clermont Auvergne, INRAE, UMR 547 PIAF, F-63000 Clermont-Ferrand, France
| | | |
Collapse
|
6
|
Yi M, Yang H, Yang S, Wang J. Overexpression of SHORT-ROOT2 transcription factor enhances the outgrowth of mature axillary buds in poplar trees. J Exp Bot 2022; 73:2469-2486. [PMID: 35107566 DOI: 10.1093/jxb/erac040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 11/13/2021] [Accepted: 02/01/2022] [Indexed: 06/14/2023]
Abstract
SHORT-ROOT (SHR) transcription factors play important roles in asymmetric cell division and radial patterning of Arabidopsis roots. In hybrid poplar (P. tremula × P. alba clone INRA 717-1B4), PtaSHR2 was preferentially expressed in axillary buds (AXBs) and transcriptionally up-regulated during AXB maturation and activation. Overexpression of SHR2 (PtSHR2OE) induced an enhanced outgrowth of AXBs below the bud maturation point, with a simultaneous transition of an active shoot apex into an arrested terminal bud. The larger and more mature AXBs of PtSHR2OE trees revealed altered expression of genes involved in axillary meristem initiation and bud activation, as well as a higher ratio of cytokinin to auxin. To elucidate the underlying mechanism of PtSHR2OE-induced high branching, subsequent molecular and biochemical studies showed that compared with wild-type trees, decapitation induced a quicker bud outburst in PtSHR2OE trees, which could be fully inhibited by exogenous application of auxin or cytokinin biosynthesis inhibitor, but not by N-1-naphthylphthalamic acid. Our results indicated that overexpression of PtSHR2B disturbed the internal hormonal balance in AXBs by interfering with the basipetal transport of auxin, rather than causing auxin biosynthesis deficiency or auxin insensitivity, thereby releasing mature AXBs from apical dominance and promoting their outgrowth.
Collapse
Affiliation(s)
- Minglei Yi
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Heyu Yang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Shaohui Yang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Jiehua Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| |
Collapse
|
7
|
Jang HA, Bae EK, Kim MH, Park SJ, Choi NY, Pyo SW, Lee C, Jeong HY, Lee H, Choi YI, Ko JH. CRISPR-Knockout of CSE Gene Improves Saccharification Efficiency by Reducing Lignin Content in Hybrid Poplar. Int J Mol Sci 2021; 22:9750. [PMID: 34575913 DOI: 10.3390/ijms22189750] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 09/03/2021] [Accepted: 09/06/2021] [Indexed: 11/16/2022] Open
Abstract
Caffeoyl shikimate esterase (CSE) has been shown to play an important role in lignin biosynthesis in plants and is, therefore, a promising target for generating improved lignocellulosic biomass crops for sustainable biofuel production. Populus spp. has two CSE genes (CSE1 and CSE2) and, thus, the hybrid poplar (Populus alba × P. glandulosa) investigated in this study has four CSE genes. Here, we present transgenic hybrid poplars with knockouts of each CSE gene achieved by CRISPR/Cas9. To knockout the CSE genes of the hybrid poplar, we designed three single guide RNAs (sg1-sg3), and produced three different transgenic poplars with either CSE1 (CSE1-sg2), CSE2 (CSE2-sg3), or both genes (CSE1/2-sg1) mutated. CSE1-sg2 and CSE2-sg3 poplars showed up to 29.1% reduction in lignin deposition with irregularly shaped xylem vessels. However, CSE1-sg2 and CSE2-sg3 poplars were morphologically indistinguishable from WT and showed no significant differences in growth in a long-term living modified organism (LMO) field-test covering four seasons. Gene expression analysis revealed that many lignin biosynthetic genes were downregulated in CSE1-sg2 and CSE2-sg3 poplars. Indeed, the CSE1-sg2 and CSE2-sg3 poplars had up to 25% higher saccharification efficiency than the WT control. Our results demonstrate that precise editing of CSE by CRISPR/Cas9 technology can improve lignocellulosic biomass without a growth penalty.
Collapse
|
8
|
Striganavičiūtė G, Žiauka J, Sirgedaitė-Šėžienė V, Vaitiekūnaitė D. Impact of Plant-Associated Bacteria on the In Vitro Growth and Pathogenic Resistance against Phellinus tremulae of Different Aspen ( Populus) Genotypes. Microorganisms 2021; 9:1901. [PMID: 34576797 DOI: 10.3390/microorganisms9091901] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 08/26/2021] [Accepted: 09/03/2021] [Indexed: 01/08/2023] Open
Abstract
Aspens (Populus tremula and its hybrids), economically and ecologically important fast-growing trees, are often damaged by Phellinus tremulae, a rot-causing fungus. Plant-associated bacteria can be used to increase plant growth and resistance; however, no systematic studies relating the activity of symbiotic bacteria to aspen resistance against Phellinus tremulae have been conducted so far. The present pioneer study investigated the responses of two Populus tremula and two P. tremula × P. tremuloides genotypes to in vitro inoculations with, first, either Pseudomonas sp. or Paenibacillus sp. bacteria (isolated originally from hybrid aspen tissue cultures and being most closely related to Pseudomonas oryzihabitans and Paenibacillus tundrae, respectively) and, in the subsequent stage, with Phellinus tremulae. Both morphological parameters of in vitro-grown plants and biochemical content of their leaves, including photosynthesis pigments and secondary metabolites, were analyzed. It was found that both Populus tremula × P. tremuloides genotypes, whose development in vitro was significantly damaged by Phellinus tremulae, were characterized by certain responses to the studied bacteria: decreased shoot development by both Paenibacillus sp. and Pseudomonas sp. and increased phenol content by Pseudomonas sp. In turn, these responses were lacking in both Populus tremula genotypes that showed in vitro resistance to the fungus. Moreover, these genotypes showed positive long-term growth responses to bacterial inoculation, even synergistic with the subsequent fungal inoculation. Hence, the studied bacteria were demonstrated as a potential tool for the improved in vitro propagation of fungus-resistant aspen genotypes.
Collapse
|
9
|
BenIsrael M, Habtewold JZ, Khosla K, Wanner P, Aravena R, Parker BL, Haack EA, Tsao DT, Dunfield KE. Identification of degrader bacteria and fungi enriched in rhizosphere soil from a toluene phytoremediation site using DNA stable isotope probing. Int J Phytoremediation 2021; 23:846-856. [PMID: 33397125 DOI: 10.1080/15226514.2020.1860901] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Improved knowledge of the ecology of contaminant-degrading organisms is paramount for effective assessment and remediation of aromatic hydrocarbon-impacted sites. DNA stable isotope probing was used herein to identify autochthonous degraders in rhizosphere soil from a hybrid poplar phytoremediation system incubated under semi-field-simulated conditions. High-throughput sequencing of bacterial 16S rRNA and fungal internal transcribed spacer (ITS) rRNA genes in metagenomic samples separated according to nucleic acid buoyant density was used to identify putative toluene degraders. Degrader bacteria were found mainly within the Actinobacteria and Proteobacteria phyla and classified predominantly as Cupriavidus, Rhodococcus, Luteimonas, Burkholderiaceae, Azoarcus, Cellulomonadaceae, and Pseudomonas organisms. Purpureocillium lilacinum and Mortierella alpina fungi were also found to assimilate toluene, while several strains of the fungal poplar endophyte Mortierella elongatus were indirectly implicated as potential degraders. Finally, PICRUSt2 predictive taxonomic functional modeling of 16S rRNA genes was performed to validate successful isolation of stable isotope-labeled DNA in density-resolved samples. Four unique sequences, classified within the Bdellovibrionaceae, Intrasporangiaceae, or Chitinophagaceae families, or within the Sphingobacteriales order were absent from PICRUSt2-generated models and represent potentially novel putative toluene-degrading species. This study illustrates the power of combining stable isotope amendment with advanced metagenomic and bioinformatic techniques to link biodegradation activity with unisolated microorganisms. Novelty statement: This study used emerging molecular biological techniques to identify known and new organisms implicated in aromatic hydrocarbon biodegradation from a field-scale phytoremediation system, including organisms with phyto-specific relevance and having potential for downstream applications (amendment or monitoring) in future and existing systems. Additional novelty in this study comes from the use of taxonomic functional modeling approaches for validation of stable isotope probing techniques. This study provides a basis for expanding existing reference databases of known aromatic hydrocarbon degraders from field-applicable sources and offers technological improvements for future site assessment and management purposes.
Collapse
Affiliation(s)
- Michael BenIsrael
- School of Environmental Sciences, University of Guelph, Guelph, Canada
| | | | - Kamini Khosla
- School of Environmental Sciences, University of Guelph, Guelph, Canada
| | - Philipp Wanner
- G360 Institute for Groundwater Research, University of Guelph, Guelph, Canada
| | - Ramon Aravena
- G360 Institute for Groundwater Research, University of Guelph, Guelph, Canada
- Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Canada
| | - Beth L Parker
- G360 Institute for Groundwater Research, University of Guelph, Guelph, Canada
| | | | - David T Tsao
- BP Corporation North America, Inc, Naperville, IL, USA
| | - Kari E Dunfield
- School of Environmental Sciences, University of Guelph, Guelph, Canada
| |
Collapse
|
10
|
Meyer JR, Li H, Zhang J, Foston MB. Kinetics of Secondary Reactions Affecting the Organosolv Lignin Structure. ChemSusChem 2020; 13:4557-4566. [PMID: 32413243 DOI: 10.1002/cssc.202000942] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 05/14/2020] [Indexed: 06/11/2023]
Abstract
Many valorization approaches for lignin rely on its organic solvent (organosolv) extraction. However, the severity of the extraction conditions required to obtain high lignin extraction generally results in low-quality lignin for downstream processing. To better understand the secondary reaction pathways and kinetics related to molecular alterations that result from organosolv extraction under extreme conditions, extractions were conducted at temperatures of 150, 180, and 210 °C. Lignin was collected at residence times between 0.25 and 18 h and analyzed by NMR techniques to quantify the concentrations of key chemical moieties that appear or disappear upon reactions of lignin molecules during and after their fractionation from biomass. The kinetics of chemical moiety evolution was modeled as processes in-series. In these models, pseudo first-order kinetics were used to describe the change in concentration of chemical moieties on extracted lignin as a function of residence time.
Collapse
Affiliation(s)
- James R Meyer
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, 1 Brookings Dr, St. Louis, MO, 63130, USA
| | - Huiyong Li
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, 1 Brookings Dr, St. Louis, MO, 63130, USA
| | - Jialiang Zhang
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, 1 Brookings Dr, St. Louis, MO, 63130, USA
| | - Marcus B Foston
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, 1 Brookings Dr, St. Louis, MO, 63130, USA
| |
Collapse
|
11
|
Biswas R, Teller PJ, Khan MU, Ahring BK. Sugar Production from Hybrid Poplar Sawdust: Optimization of Enzymatic Hydrolysis and Wet Explosion Pretreatment. Molecules 2020; 25:E3396. [PMID: 32727071 PMCID: PMC7436106 DOI: 10.3390/molecules25153396] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 07/20/2020] [Accepted: 07/20/2020] [Indexed: 01/08/2023] Open
Abstract
Wet explosion pretreatment of hybrid poplar sawdust (PSD) for the production of fermentable sugar was carried out in the pilot-scale. The effects of pretreatment conditions, such as temperature (170-190 °C), oxygen dosage (0.5-7.5% of dry matter (DM), w/w), residence time (10-30 min), on cellulose and hemicellulose digestibility after enzymatic hydrolysis were ascertained with a central composite design of the experiment. Further, enzymatic hydrolysis was optimized in terms of temperature, pH, and a mixture of CTec2 and HTec2 enzymes (Novozymes). Predictive modeling showed that cellulose and hemicellulose digestibility of 75.1% and 83.1%, respectively, could be achieved with a pretreatment at 177 °C with 7.5% O2 and a retention time of 30 min. An increased cellulose digestibility of 87.1% ± 0.1 could be achieved by pretreating at 190 °C; however, the hemicellulose yield would be significantly reduced. It was evident that more severe conditions were required for maximal cellulose digestibility than that of hemicellulose digestibility and that an optimal sugar yield demanded a set of conditions, which overall resulted in the maximum sugar yield.
Collapse
Affiliation(s)
- Rajib Biswas
- Bioproducts, Sciences and Engineering Laboratory, Washington State University, Tri-Cities, 2710, Crimson Way, Richland, WA 99354, USA; (R.B.); (P.J.T.); (M.U.K.)
| | - Philip J. Teller
- Bioproducts, Sciences and Engineering Laboratory, Washington State University, Tri-Cities, 2710, Crimson Way, Richland, WA 99354, USA; (R.B.); (P.J.T.); (M.U.K.)
| | - Muhammad U. Khan
- Bioproducts, Sciences and Engineering Laboratory, Washington State University, Tri-Cities, 2710, Crimson Way, Richland, WA 99354, USA; (R.B.); (P.J.T.); (M.U.K.)
- Biological Systems Engineering, L.J. Smith Hall, Washington State University, Pullman, WA 99164, USA
| | - Birgitte K. Ahring
- Bioproducts, Sciences and Engineering Laboratory, Washington State University, Tri-Cities, 2710, Crimson Way, Richland, WA 99354, USA; (R.B.); (P.J.T.); (M.U.K.)
- Biological Systems Engineering, L.J. Smith Hall, Washington State University, Pullman, WA 99164, USA
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99163, USA
| |
Collapse
|
12
|
Da Ros LM, Mansfield SD. Biotechnological mechanism for improving plant remobilization of phosphorus during leaf senescence. Plant Biotechnol J 2020; 18:470-478. [PMID: 31325405 PMCID: PMC6953190 DOI: 10.1111/pbi.13212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 08/23/2018] [Revised: 05/23/2019] [Accepted: 07/11/2019] [Indexed: 05/08/2023]
Abstract
Phosphorus enrichment of aquatic ecosystems through diffuse source pollution is an ongoing issue worldwide. A potential solution lies in the use of fast-growing, multipurpose feedstocks, such as trees, to limit the flow of phosphorus into riparian areas through luxury consumption. However, the perennial nature of trees and their use of leaves as storage organs for excess phosphorus may reduce the effectiveness of contaminant removal during periods of leaf abscission. In an attempt to improve phosphorus remobilization during autumnal senescence, transgenic hybrid poplar P39 (Populus alba × Populus grandidentata) and Arabidopsis thaliana harbouring a constitutively expressed low-affinity potato phosphate transporter (35S::StPht1-1) were generated using Agrobacterium-mediated transformation. For both species, the highest expressing 35S::StPht1-1 lines were grown alongside wild-type plants and subjected to increasing phosphate applications. StPht1-1 expression in A. thaliana led to a reduction in biomass when grown under high-phosphate conditions and had no effect on phosphate remobilization during senescence. In contrast, StPht1-1 constitutive expression in P39 resulted in increased leaf phosphate content in the highest expressing transgenic line and minimal to no effect on P resorption efficiency. Surprisingly, sulphate resorption showed the greatest improvement in all three transgenic poplar lines, displaying a 31%-37% increase in resorption efficiency. These results highlight the complexity of nutrient resorption mechanisms in plants.
Collapse
Affiliation(s)
- Letitia M. Da Ros
- Department of Wood ScienceUniversity of British ColumbiaVancouverBCCanada
| | - Shawn D. Mansfield
- Department of Wood ScienceUniversity of British ColumbiaVancouverBCCanada
| |
Collapse
|
13
|
Lu D, Yuan X, Kim S, Marques JV, Chakravarthy PP, Moinuddin SGA, Luchterhand R, Herman B, Davin LB, Lewis NG. Eugenol specialty chemical production in transgenic poplar (Populus tremula × P. alba) field trials. Plant Biotechnol J 2017; 15:970-981. [PMID: 28064439 PMCID: PMC5506655 DOI: 10.1111/pbi.12692] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [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: 10/17/2016] [Revised: 12/20/2016] [Accepted: 01/05/2017] [Indexed: 05/09/2023]
Abstract
A foundational study assessed effects of biochemical pathway introduction into poplar to produce eugenol, chavicol, p-anol, isoeugenol and their sequestered storage products, from potentially available substrates, coniferyl and p-coumaryl alcohols. At the onset, it was unknown whether significant carbon flux to monolignols vs. other phenylpropanoid (acetate) pathway metabolites would be kinetically favoured. Various transgenic poplar lines generated eugenol and chavicol glucosides in ca. 0.45% (~0.35 and ~0.1%, respectively) of dry weight foliage tissue in field trials, as well as their corresponding aglycones in trace amounts. There were only traces of any of these metabolites in branch tissues, even after ~4-year field trials. Levels of bioproduct accumulation in foliage plateaued, even at the lowest introduced gene expression levels, suggesting limited monolignol substrate availability. Nevertheless, this level still allows foliage collection for platform chemical production, with the remaining (stem) biomass available for wood, pulp/paper and bioenergy product purposes. Several transformed lines displayed unexpected precocious flowering after 4-year field trial growth. This necessitated terminating (felling) these particular plants, as USDA APHIS prohibits the possibility of their interacting (cross-pollination, etc.) with wild-type (native plant) lines. In future, additional biotechnological approaches can be employed (e.g. gene editing) to produce sterile plant lines, to avoid such complications. While increased gene expression did not increase target bioproduct accumulation, the exciting possibility now exists of significantly increasing their amounts (e.g. 10- to 40-fold plus) in foliage and stems via systematic deployment of numerous 'omics', systems biology, synthetic biology and metabolic flux modelling approaches.
Collapse
Affiliation(s)
- Da Lu
- Institute of Biological ChemistryWashington State UniversityPullmanWAUSA
| | - Xianghe Yuan
- Institute of Biological ChemistryWashington State UniversityPullmanWAUSA
| | - Sung‐Jin Kim
- Institute of Biological ChemistryWashington State UniversityPullmanWAUSA
| | - Joaquim V. Marques
- Institute of Biological ChemistryWashington State UniversityPullmanWAUSA
| | | | | | - Randi Luchterhand
- Puyallup Research and Extension CenterWashington State UniversityPuyallupWAUSA
| | - Barri Herman
- Institute of Biological ChemistryWashington State UniversityPullmanWAUSA
- Puyallup Research and Extension CenterWashington State UniversityPuyallupWAUSA
| | - Laurence B. Davin
- Institute of Biological ChemistryWashington State UniversityPullmanWAUSA
| | - Norman G. Lewis
- Institute of Biological ChemistryWashington State UniversityPullmanWAUSA
| |
Collapse
|
14
|
Théroux Rancourt G, Éthier G, Pepin S. Greater efficiency of water use in poplar clones having a delayed response of mesophyll conductance to drought. Tree Physiol 2015; 35:172-84. [PMID: 25721370 DOI: 10.1093/treephys/tpv006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Improvement of water use efficiency is a key objective to improve the sustainability of cultivated plants, especially fast growing species with high water consumption like poplar. It is well known that water use efficiency (WUE) varies considerably among poplar genotypes, and it was recently suggested that the use of the mesophyll-to-stomatal conductance ratio (gm/gs) would be an appropriate trait to improve WUE. The responses of 7-week-old cuttings of four hybrid poplar clones and one native Balsam poplar (Populus balsamifera L.) to a water stress-recovery cycle were examined to evaluate the relation between the gm/gs ratio and transpiration efficiency (TE), a leaf-level component of WUE. A contrasting gs response to water stress was observed among the five clones, from stomatal closure early on during soil drying up to limited closure in Balsam poplar. However in the hybrids, the decline in gm was consistently delayed by a few days compared with gs. Moreover, in the most water use-efficient hybrids, the recovery following rehydration occurred faster for gm than for gs. Thus, the delay in the response of gm to drought and its faster recovery upon rewatering increased the gm/gs of the hybrids and this ratio scaled positively with TE. Our results support the use of the gm/gs ratio to select genotypes with improved WUE, and the notion that breeding strategies focusing mainly on stomatal responses to soil drying should also look for a strong curvilinearity between net carbon assimilation rate and gs, the indication of a significant increase in gm/gs in the earlier stages of stomatal closure.
Collapse
Affiliation(s)
- Guillaume Théroux Rancourt
- Department of Plant Sciences, Horticultural Research Center, Université Laval, Québec, QC, Canada, G1V 0A6
| | - Gilbert Éthier
- Department of Plant Sciences, Horticultural Research Center, Université Laval, Québec, QC, Canada, G1V 0A6
| | - Steeve Pepin
- Department of Soil and Agri-Food Engineering, Horticultural Research Center, Université Laval, Québec, QC, Canada, G1V 0A6
| |
Collapse
|
15
|
Barigah TS, Charrier O, Douris M, Bonhomme M, Herbette S, Améglio T, Fichot R, Brignolas F, Cochard H. Water stress-induced xylem hydraulic failure is a causal factor of tree mortality in beech and poplar. Ann Bot 2013; 112:1431-7. [PMID: 24081280 PMCID: PMC3806533 DOI: 10.1093/aob/mct204] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [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: 05/07/2013] [Accepted: 07/22/2013] [Indexed: 05/18/2023]
Abstract
BACKGROUND AND AIMS Extreme water stress episodes induce tree mortality, but the physiological mechanisms causing tree death are still poorly understood. This study tests the hypothesis that a potted tree's ability to survive extreme monotonic water stress is determined by the cavitation resistance of its xylem tissue. METHODS Two species were selected with contrasting cavitation resistance (beech and poplar), and potted juvenile trees were exposed to a range of water stresses, causing up to 100 % plant death. KEY RESULTS The lethal dose of water stress, defined as the xylem pressure inducing 50 % mortality, differed sharply across species (1·75 and 4·5 MPa in poplar and beech, respectively). However, the relationships between tree mortality and the degree of cavitation in the stems were similar, with mortality occurring suddenly when >90 % cavitation had occurred. CONCLUSIONS Overall, the results suggest that cavitation resistance is a causal factor of tree mortality under extreme drought conditions.
Collapse
Affiliation(s)
- Têtè Sévérien Barigah
- INRA, UMR547 PIAF, F-63100 Clermont-Ferrand, France
- Clermont Université, Université Blaise-Pascal, UMR547 PIAF, BP 10448, F-63000 Clermont-Ferrand, France
| | - Olivia Charrier
- Clermont Université, Université Blaise-Pascal, UMR547 PIAF, BP 10448, F-63000 Clermont-Ferrand, France
- Université de Toulouse, ENFA; UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), F-31062 Toulouse, France
- CNRS, Université Paul Sabatier; UMR5174 EDB, F-31062 Toulouse, France
| | - Marie Douris
- INRA, UMR547 PIAF, F-63100 Clermont-Ferrand, France
- Clermont Université, Université Blaise-Pascal, UMR547 PIAF, BP 10448, F-63000 Clermont-Ferrand, France
| | - Marc Bonhomme
- INRA, UMR547 PIAF, F-63100 Clermont-Ferrand, France
- Clermont Université, Université Blaise-Pascal, UMR547 PIAF, BP 10448, F-63000 Clermont-Ferrand, France
| | - Stéphane Herbette
- INRA, UMR547 PIAF, F-63100 Clermont-Ferrand, France
- Clermont Université, Université Blaise-Pascal, UMR547 PIAF, BP 10448, F-63000 Clermont-Ferrand, France
| | - Thierry Améglio
- INRA, UMR547 PIAF, F-63100 Clermont-Ferrand, France
- Clermont Université, Université Blaise-Pascal, UMR547 PIAF, BP 10448, F-63000 Clermont-Ferrand, France
| | - Régis Fichot
- Université d'Orléans, Faculté des Sciences, Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), UPRES EA 1207, F-45067 Orléans, France
- INRA, USC1328 ARCHE, F-45067 Orléans, France
- INRA, UR588 AGPF, F-45075 Orléans, France
| | - Frank Brignolas
- Université d'Orléans, Faculté des Sciences, Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), UPRES EA 1207, F-45067 Orléans, France
- INRA, USC1328 ARCHE, F-45067 Orléans, France
| | - Hervé Cochard
- INRA, UMR547 PIAF, F-63100 Clermont-Ferrand, France
- Clermont Université, Université Blaise-Pascal, UMR547 PIAF, BP 10448, F-63000 Clermont-Ferrand, France
| |
Collapse
|
16
|
Li Z, Chen CH, Hegg EL, Hodge DB. Rapid and effective oxidative pretreatment of woody biomass at mild reaction conditions and low oxidant loadings. Biotechnol Biofuels 2013; 6:119. [PMID: 23971902 PMCID: PMC3765420 DOI: 10.1186/1754-6834-6-119] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 08/20/2013] [Indexed: 05/09/2023]
Abstract
BACKGROUND One route for producing cellulosic biofuels is by the fermentation of lignocellulose-derived sugars generated from a pretreatment that can be effectively coupled with an enzymatic hydrolysis of the plant cell wall. While woody biomass exhibits a number of positive agronomic and logistical attributes, these feedstocks are significantly more recalcitrant to chemical pretreatments than herbaceous feedstocks, requiring higher chemical and energy inputs to achieve high sugar yields from enzymatic hydrolysis. We previously discovered that alkaline hydrogen peroxide (AHP) pretreatment catalyzed by copper(II) 2,2΄-bipyridine complexes significantly improves subsequent enzymatic glucose and xylose release from hybrid poplar heartwood and sapwood relative to uncatalyzed AHP pretreatment at modest reaction conditions (room temperature and atmospheric pressure). In the present work, the reaction conditions for this catalyzed AHP pretreatment were investigated in more detail with the aim of better characterizing the relationship between pretreatment conditions and subsequent enzymatic sugar release. RESULTS We found that for a wide range of pretreatment conditions, the catalyzed pretreatment resulted in significantly higher glucose and xylose enzymatic hydrolysis yields (as high as 80% for both glucose and xylose) relative to uncatalyzed pretreatment (up to 40% for glucose and 50% for xylose). We identified that the extent of improvement in glucan and xylan yield using this catalyzed pretreatment approach was a function of pretreatment conditions that included H2O2 loading on biomass, catalyst concentration, solids concentration, and pretreatment duration. Based on these results, several important improvements in pretreatment and hydrolysis conditions were identified that may have a positive economic impact for a process employing a catalyzed oxidative pretreatment. These improvements include identifying that: (1) substantially lower H2O2 loadings can be used that may result in up to a 50-65% decrease in H2O2 application (from 100 mg H2O2/g biomass to 35-50 mg/g) with only minor losses in glucose and xylose yield, (2) a 60% decrease in the catalyst concentration from 5.0 mM to 2.0 mM (corresponding to a catalyst loading of 25 μmol/g biomass to 10 μmol/g biomass) can be achieved without a subsequent loss in glucose yield, (3) an order of magnitude improvement in the time required for pretreatment (minutes versus hours or days) can be realized using the catalyzed pretreatment approach, and (4) enzyme dosage can be reduced to less than 30 mg protein/g glucan and potentially further with only minor losses in glucose and xylose yields. In addition, we established that the reaction rate is improved in both catalyzed and uncatalyzed AHP pretreatment by increased solids concentrations. CONCLUSIONS This work explored the relationship between reaction conditions impacting a catalyzed oxidative pretreatment of woody biomass and identified that significant decreases in the H2O2, catalyst, and enzyme loading on the biomass as well as decreases in the pretreatment time could be realized with only minor losses in the subsequent sugar released enzymatically. Together these changes would have positive implications for the economics of a process based on this pretreatment approach.
Collapse
Affiliation(s)
- Zhenglun Li
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, USA
- DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, USA
| | - Charles H Chen
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, USA
- DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, USA
| | - Eric L Hegg
- DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, USA
- Department of Biochemistry & Molecular Biology, Michigan State University, East Lansing, USA
| | - David B Hodge
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, USA
- DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, USA
- Department of Biosystems & Agricultural Engineering, Michigan State University, East Lansing, USA
- Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| |
Collapse
|
17
|
Unda F, Canam T, Preston L, Mansfield SD. Isolation and characterization of galactinol synthases from hybrid poplar. J Exp Bot 2012; 63:2059-69. [PMID: 22197892 PMCID: PMC3295395 DOI: 10.1093/jxb/err411] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [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: 09/12/2011] [Revised: 11/15/2011] [Accepted: 11/17/2011] [Indexed: 05/20/2023]
Abstract
The raffinose family of oligosaccharides (RFOs) serve as transport carbohydrates in the phloem, storage compounds in sink tissues, and putative biological agents to combat both abiotic and biotic stress in several plant species. To investigate further the functional roles of this class of compounds in trees, two cDNAs encoding galactinol synthase (GolS, EC 2.4.1.123), which catalyses the first step in the biosynthesis of RFOs, were identified and cloned from hybrid poplar (Populus alba×grandidentata). Phylogenetic analyses of the Populus GolS isoforms with other known GolS proteins suggested a putative role for these enzymes during biotic or abiotic stress in hybrid poplar. The predicted protein sequences of both isoforms (Pa×gGolSI and Pa×gGolSII) showed characteristics of GolS proteins from other species, including a serine phosphorylation site and the ASAAP pentapeptide hydrophobic domain. Kinetic analyses of recombinant Pa×gGolSI and Pa×gGolSII resulted in K(m) values for UPD-galactose of 0.80 and 0.65 mM and V(max) values of 657.5 and 1245 nM min(-1), respectively. Pa×gGolSI inherently possessed a broader pH and temperature range when compared with Pa×gGolSII. Interestingly, spatial and temporal expression analyses revealed that Pa×gGolSII transcript levels varied seasonally, while Pa×gGolSI did not, implying temperature-regulated transcriptional control of this gene in addition to the observed thermosensitivity of the respective enzyme. This evidence suggested that Pa×gGolSI may be involved in basic metabolic activities such as storage, while Pa×gGolSII is probably involved in seasonal mobilization of carbohydrates.
Collapse
Affiliation(s)
- Faride Unda
- Department of Wood Science, Faculty of Forestry, The University of British Columbia, 2424 Main Mall, V6T 1Z4, Vancouver, BC, Canada
| | - Thomas Canam
- Department of Biological Sciences, Eastern Illinois University, 600 Lincoln Avenue, Charleston, IL 61920-3099, USA
| | - Lindsay Preston
- Department of Wood Science, Faculty of Forestry, The University of British Columbia, 2424 Main Mall, V6T 1Z4, Vancouver, BC, Canada
| | - Shawn D. Mansfield
- Department of Wood Science, Faculty of Forestry, The University of British Columbia, 2424 Main Mall, V6T 1Z4, Vancouver, BC, Canada
- To whom correspondence should be addressed. E-mail: Shawn D. Mansfield
| |
Collapse
|
18
|
Delagrange S, Rochon P. Reconstruction and analysis of a deciduous sapling using digital photographs or terrestrial-LiDAR technology. Ann Bot 2011; 108:991-1000. [PMID: 21515607 PMCID: PMC3189831 DOI: 10.1093/aob/mcr064] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [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: 12/03/2010] [Accepted: 02/10/2011] [Indexed: 05/21/2023]
Abstract
BACKGROUND AND AIMS To meet the increasing need for rapid and non-destructive extraction of canopy traits, two methods were used and compared with regard to their accuracy in estimating 2-D and 3-D parameters of a hybrid poplar sapling. METHODS The first method consisted of the analysis of high definition photographs in Tree Analyser (TA) software (PIAF-INRA/Kasetsart University). TA allowed the extraction of individual traits using a space carving approach. The second method utilized 3-D point clouds acquired from terrestrial light detection and ranging (T-LiDAR) scans. T-LiDAR scans were performed on trees without leaves to reconstruct the lignified structure of the sapling. From this skeleton, foliage was added using simple modelling rules extrapolated from field measurements. Validation of the estimated dimension and the accuracy of reconstruction was then achieved by comparison with an empirical data set. KEY RESULTS TA was found to be slightly less precise than T-LiDAR for estimating tree height, canopy height and mean canopy diameter, but for 2-D traits both methods were, however, fully satisfactory. TA tended to over-estimate total leaf area (error up to 50 %), but better estimates were obtained by reducing the size of the voxels used for calculations. In contrast, T-LiDAR estimated total leaf area with an error of <6 %. Finally, both methods led to an over-estimation of canopy volume. With respect to this trait, T-LiDAR (14·5 % deviation) greatly surpassed the accuracy of TA (up to 50 % deviation), even if the voxels used were reduced in size. CONCLUSIONS Taking into account their magnitude of data acquisition and analysis and their accuracy in trait estimations, both methods showed contrasting potential future uses. Specifically, T-LiDAR is a particularly promising tool for investigating the development of large perennial plants, by itself or in association with plant modelling.
Collapse
|
19
|
Abstract
Intensive forestry systems and breeding programs often include either native aspen or hybrid poplar clones, and performance and trait evaluations are mostly made within these two groups. Here, we assessed how traits with potential adaptive value varied within and across these two plant groups. Variation in nine hydraulic and wood anatomical traits as well as growth were measured in selected aspen and hybrid poplar genotypes grown at a boreal planting site in Alberta, Canada. Variability in these traits was statistically evaluated based on a blocked experimental design. We found that genotypes of trembling aspen were more resistant to cavitation, exhibited more negative water potentials, and were more water-use-efficient than hybrid poplars. Under the boreal field test conditions, which included major regional droughts, height growth was negatively correlated with branch vessel diameter (Dv ) in both aspen and hybrid poplars and differences in Dv were highly conserved in aspen trees from different provenances. Differences between the hybrid poplars and aspen provenances suggest that these two groups employ different water-use strategies. The data also suggest that vessel diameter may be a key trait in evaluating growth performance in a boreal environment.
Collapse
Affiliation(s)
- Stefan G Schreiber
- Department of Renewable Resources, University of Alberta, 739 General Services Building, Edmonton, AB, Canada T6G 2H1
| | - Uwe G Hacke
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, AB, Canada T6G 2E3
| | - Andreas Hamann
- Department of Renewable Resources, University of Alberta, 739 General Services Building, Edmonton, AB, Canada T6G 2H1
| | - Barb R Thomas
- Department of Renewable Resources, University of Alberta, 739 General Services Building, Edmonton, AB, Canada T6G 2H1
- Alberta-Pacific Forest Industries Inc., Box 8000, Boyle, AB, Canada T0A 0M0
| |
Collapse
|
20
|
Cline MG, Dong-IL K. A preliminary investigation of the role of auxin and cytokinin in sylleptic branching of three hybrid poplar clones exhibiting contrasting degrees of sylleptic branching. Ann Bot 2002; 90:417-21. [PMID: 12234154 PMCID: PMC4240395 DOI: 10.1093/aob/mcf195] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Sylleptic branches grow out from lateral buds during the same growing season in which the buds are formed. This type of branching is present in poplar and in many tropical species. It results in the production of more branches, more leaves and expanded photosynthetic capacity and is thought to assist in increasing the overall growth and biomass of the tree at a young age. However, very little is known about the physiology of sylleptic branching in poplar, which is an extremely important source of fibre and fuel. In the present study of three hybrid poplar clones (11-11, 47-174 and 49-177) of Populus trichocarpa x P. deltoides exhibiting contrasting degrees of sylleptic branching, an analysis was carried out on parent shoot elongation and sylleptic branching, together with a preliminary comparison of the parent shoots' sensitivity to auxin (naphthaleneacetic acid) as a repressor of lateral bud outgrowth, and cytokinin (benzyladenine) as a promoter. Suggestive evidence was found for an inverse correlation between parent shoot sensitivity to auxin and the degree of sylleptic branching, as well as a partially positive correlation with respect to sensitivity to cytokinin. The present data are consistent with the hypothesis that auxin and cytokinin may play repressive and promotive roles, respectively, in the sylleptic branching of hybrid poplar.
Collapse
Affiliation(s)
- Morris G Cline
- Department of Plant Biology, Ohio State University, Columbus 43210, USA.
| | | |
Collapse
|
21
|
Abstract
Leaf extension was stimulated following exposure of three interamerican hybrid poplar clones (Populus trichocarpa P. deltoides); 'Unal', 'Boelare', and 'Beaupre' and a euramerican clone 'Primo' (Populus nigra×P. deltoides) to elevated CO2 , in controlled environment chambers. For all three interamerican clones the evidence suggests that this was the result of increased leaf cell expansion associated with enhanced cell wall extensibility (WEx), measured as tensiomerric increases in cell wall plasticity. For the interameriean clone 'Boelare', there was also a significant increase in cell wall elasticity following exposure to elevated CO2 (P⩽ 0.001). The effect of elevated CO2 in stimulating cell wall extensibility was confirmed in a detailed spatial analysis of extensibility made across the lamina of expanding leaves of the clone 'Boelare'. For two of the interamerican hybrids, 'Unal' and 'Beaupre', both leaf cell water potential Ψ and turgor pressure (P) were lower in elevated than in ambient CO2 . By contrast, no significant effects on the cell wall properties or leaf water relations for the euramerican hybrid 'Primo' were observed following exposure to elevated CO2 . suggesting that the mechanism for increased leaf extension in elevated CO2 , differed, depending on clone. The cumulative total length of leaves of 'Boelare' grown in elevated CO2 , was significantly increased (P≤ 0.05) and since leaf number was not significantly increased in any inter-american clone it is hypothesized that final leaf size was stimulated in elevated CO2 for these clones. By contrast, there was no significant effect of CO2 on cumulative total leaf length for the euramerican clone 'Primo', but leaf number was significantly increased by elevated CO2 . The measurements suggest that total tree leaf area was stimulated for a range of poplar hybrids exposed to elevated CO2 . Given the short rotation of a coppiced crop, it is likely that increased leaf areas will result in enhanced stemwood production when hybrid poplars are grown in the CO, concentrations predicted for the next century.
Collapse
Affiliation(s)
- Simon D L Gardner
- School of Biological Sciences, University of Sussex, Falmer, Brighton, Sussex BN1 9QG, UK
| | - Gail Taylor
- School of Biological Sciences, University of Sussex, Falmer, Brighton, Sussex BN1 9QG, UK
| | - Creana Bosac
- School of Biological Sciences, University of Sussex, Falmer, Brighton, Sussex BN1 9QG, UK
| |
Collapse
|