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

Harding, Scott A.¹  Tsai, Chung-Jui¹ 

[1] Univ. of Georgia, Athens, GA (United States)

关键词: sucrose;    woody biomass;    growth;    carbon partitioning;    water use;   

DOI  :  10.2172/1233533
RP-ID  :  DOE-UGA--0005140
PID  :  OSTI ID: 1233533

学科分类：生物科学（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

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).