skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Organ and Tissue-specific Sucrose Transporters. Important Hubs in Gene and Metabolite Networks Regulating Carbon Use in Wood-forming Tissues of Populus

Abstract

The overall project objective was to probe the relationship between sucrose transporters and plant productivity in the biomass for biofuels woody perennial, Populus. At the time the proposal was written, sucrose transporters had already been investigated in many plant model systems, primarily with respect to the export of photosynthate sucrose from source leaves, and the uptake of sucrose in storage organs and seeds. Preliminary findings by the PI found that in Populus, sucrose transporter genes (SUTs) were well expressed in wood-forming tissues that comprise the feedstock for biofuels production. Because sucrose comprises by far the predominant form in which photosynthate is delivered from source organs to sink organs like roots and wood-forming tissues, SUTs control a gate that nominally at least could impact the allocation or partitioning of sucrose for potentially competing end uses like growth (stem biomass) and storage. In addition, water use might be conditioned by the way in which sucrose is distributed throughout the plant, and/or by the way in which sucrose is partitioned intracellularly. Several dozen transgenic lines were produced in year 1 of the project to perturb the expression ratio of multiple plasma membrane (PM) SUTs (intercellular trafficking), versus the single tonoplast membrane (TM) sucrosemore » transporter that effectively regulates intracellular trafficking of sucrose. It was possible to obtain transgenic lines with dual SUT gene knockdown using the 35S promoter, but not the wood-specific TUA1 promoter. By the end of project year 2, a decision was made to work with the 35S plants while archiving the TUA1 plants. The PhD candidate charged with producing the transgenic lines abandoned the project during its second year, substantially contributing to the decision to operate with just the 35S lines. That student’s interests ranged more toward evolutionary topics, and a report on SUT gene evolution was published (Peng et al 2014).« less

Authors:
 [1]; ORCiD logo [1]
  1. Univ. of Georgia, Athens, GA (United States)
Publication Date:
Research Org.:
Univ. of Georgia, Athens, GA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
OSTI Identifier:
1233533
Report Number(s):
DOE-UGA-0005140
DOE Contract Number:
sc0005140
Resource Type:
Technical Report
Resource Relation:
Related Information: The Tonoplast-Localized Sucrose Transporter in Populus (PtaSUT4) Regulates Whole-Plant Water Relations, Responses to Water Stress, and PhotosynthesisFrost, CJ; Nyamdari, B; Tsai, CJ; Harding, SA(2012) PLOS ONE vol. 7:8 Article Number: e44467DOI: 10.1371/journal.pone.0044467 Bayesian phylogeny of sucrose transporters: ancient origins, differential expansion and convergent evolution in monocots and dicotsPeng, D; Gu, X; Xue, LJ; Leebens-Mack, JH; Tsai, CJ (2014) FRONTIERS IN PLANT SCIENCE vol. 5DOI: 10.3389/fpls.2014.00615 NCBI submissions:RNASeq accession numbers SRP041959; SRP059838
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; sucrose; woody biomass; growth; carbon partitioning; water use

Citation Formats

Harding, Scott A., and Tsai, Chung-Jui. Organ and Tissue-specific Sucrose Transporters. Important Hubs in Gene and Metabolite Networks Regulating Carbon Use in Wood-forming Tissues of Populus. United States: N. p., 2016. Web. doi:10.2172/1233533.
Harding, Scott A., & Tsai, Chung-Jui. Organ and Tissue-specific Sucrose Transporters. Important Hubs in Gene and Metabolite Networks Regulating Carbon Use in Wood-forming Tissues of Populus. United States. doi:10.2172/1233533.
Harding, Scott A., and Tsai, Chung-Jui. 2016. "Organ and Tissue-specific Sucrose Transporters. Important Hubs in Gene and Metabolite Networks Regulating Carbon Use in Wood-forming Tissues of Populus". United States. doi:10.2172/1233533. https://www.osti.gov/servlets/purl/1233533.
@article{osti_1233533,
title = {Organ and Tissue-specific Sucrose Transporters. Important Hubs in Gene and Metabolite Networks Regulating Carbon Use in Wood-forming Tissues of Populus},
author = {Harding, Scott A. and Tsai, Chung-Jui},
abstractNote = {The overall project objective was to probe the relationship between sucrose transporters and plant productivity in the biomass for biofuels woody perennial, Populus. At the time the proposal was written, sucrose transporters had already been investigated in many plant model systems, primarily with respect to the export of photosynthate sucrose from source leaves, and the uptake of sucrose in storage organs and seeds. Preliminary findings by the PI found that in Populus, sucrose transporter genes (SUTs) were well expressed in wood-forming tissues that comprise the feedstock for biofuels production. Because sucrose comprises by far the predominant form in which photosynthate is delivered from source organs to sink organs like roots and wood-forming tissues, SUTs control a gate that nominally at least could impact the allocation or partitioning of sucrose for potentially competing end uses like growth (stem biomass) and storage. In addition, water use might be conditioned by the way in which sucrose is distributed throughout the plant, and/or by the way in which sucrose is partitioned intracellularly. Several dozen transgenic lines were produced in year 1 of the project to perturb the expression ratio of multiple plasma membrane (PM) SUTs (intercellular trafficking), versus the single tonoplast membrane (TM) sucrose transporter that effectively regulates intracellular trafficking of sucrose. It was possible to obtain transgenic lines with dual SUT gene knockdown using the 35S promoter, but not the wood-specific TUA1 promoter. By the end of project year 2, a decision was made to work with the 35S plants while archiving the TUA1 plants. The PhD candidate charged with producing the transgenic lines abandoned the project during its second year, substantially contributing to the decision to operate with just the 35S lines. That student’s interests ranged more toward evolutionary topics, and a report on SUT gene evolution was published (Peng et al 2014).},
doi = {10.2172/1233533},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2016,
month = 1
}

Technical Report:

Save / Share:
  • Adoption of biofuels as economically and environmentally viable alternative to fossil fuels would require development of specialized bioenergy varieties. A major goal in the breeding of such varieties is the improvement of lignocellulosic biomass yield and quality. These are complex traits and understanding the underpinning molecular mechanism can assist and accelerate their improvement. This is particularly important for tree bioenergy crops like poplars (species and hybrids from the genus Populus), for which breeding progress is extremely slow due to long generation cycles. A variety of approaches have been already undertaken to better understand the molecular bases of biomass yield andmore » quality in poplar. An obvious void in these undertakings has been the application of mutagenesis. Mutagenesis has been instrumental in the discovery and characterization of many plant traits including such that affect biomass yield and quality. In this proposal we use activation tagging to discover genes that can significantly affect biomass associated traits directly in poplar, a premier bioenergy crop. We screened a population of 5,000 independent poplar activation tagging lines under greenhouse conditions for a battery of biomass yield traits. These same plants were then analyzed for changes in wood chemistry using pyMBMS. As a result of these screens we have identified nearly 800 mutants, which are significantly (P<0.05) different when compared to wild type. Of these majority (~700) are affected in one of ten different biomass yield traits and 100 in biomass quality traits (e.g., lignin, S/G ration and C6/C5 sugars). We successfully recovered the position of the tag in approximately 130 lines, showed activation in nearly half of them and performed recapitulation experiments with 20 genes prioritized by the significance of the phenotype. Recapitulation experiments are still ongoing for many of the genes but the results are encouraging. For example, we have shown successful recapitulation for a fascilin-like gene that when overexpressed increase many biomass-yield associated traits. Genes discovered through activation tagging showed polymorphisms in P. trichocarpa association mapping population linked to the traits modified by the activation tagging. This suggests that putative alleles that are associated with improvement of the trait o interest can be discovered and used in marker associated selection. This will significantly simplify and accelerate the breeding efforts.« less
  • A computer program is described which calculates doses averaged within five major segments of the blood forming organ in the human body taking into account selfshielding of the detailed body geometry and nuclear star effects for proton radiation of arbitrary energy spectrum (energy less than 1 GeV) and isotropic angular distribution. The dose calculation includes the first term of an asymptotic series expansion of transport theory which is known to converge rapidly for most points in the human body. The result is always a conservative estimate of dose and is given as physical dose (rad) and dose equivalent (rem). (STAR)
  • Transcriptional regulation is the primary step to control gene expression, therefore function. Such regulation is achieved primarily via a combination of the activities of the promoter cis regulatory DNA elements and trans regulatory proteins that function through binding to these DNA elements. Rice bZIP transcription factors RF2a, RF2b and RLP1 play key roles in regulating the activity of a vascular tissue specific promoter isolated from Rice Tungro Bacilliform Virus (RTBV), through their interactions with the Box II essential cis element located in the promoter (Dai et al., 2006., Dai et al., 2004., Yin et al., 1997). RF2a, RF2b and RLP1more » possess multiple regulatory domains. Functional characterization reveals that those domains can activate or repress the activity of the RTBV promoter. It is equally as important to recognize that these proteins control plant development by regulating differentiation and/or function of the vascular tissues. Studies of transcriptional regulation of the RTBV promoter by this group of bZIP proteins will not only provide insights about gene expression in the vascular tissue, but also insights about general mechanisms of transcription activation and repression. The knowledge gained from this research will also enable us to develop a well-described set of tools that can be used to control expression of multiple genes in transgenic plants. We have proposed characterize the function domains of RF2a, RF2b and RLP1 and explore the biological function of the transcription repressor RLP1.« less