RNA-Seq Analysis of Developing Nasturtium Seeds （Tropaeolum majus）： Identification and Characterization of an Additional Galactosyltransferase Involved in Xyloglucan Biosynthesis  

作　　者：Jacob K. Jensen Alex Schultink Kenneth Keegstra Curtis G. Wilkerson Markus Pauly 

机构地区：[1]DOE Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI 48824, USA [2]Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA [3]Department of Plant and Microbial Biology, UC Berkeley, Berkeley, CA 94720, USA [4]MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA [5]Energy Biosciences Institute, University of California, Berkeley, 30 Calvin Hall, MC 5230, Berkeley, CA 94720, USA

出　　处：《Molecular Plant》2012年第5期984-992,共9页分子植物（英文版）

摘　　要：A deep-sequencing approach was pursued utilizing 454 and Illumina sequencing methods to discover new genes involved in xyloglucan biosynthesis, cDNA sequences were generated from developing nasturtium （Tropaeolum majus） seeds, which produce large amounts of non-fucosylated xyloglucan as a seed storage polymer. In addition to known xyloglucan biosynthetic genes, a previously uncharacterized putative xyloglucan galactosyltransferase was iden- tified. Analysis of an Arabidopsis thaliana mutant line defective in the corresponding ortholog （AT5G62220） revealed that this gene shows no redundancy with the previously characterized xyloglucan galactosyltransferase, MUR3, but is required for galactosyl-substitution of xyloglucan at a different position. The gene was termed XLT2 for Xyloglucan L-side chain galactosylTransferase position 2. It represents an enzyme in the same subclade of glycosyltransferase family 47 as MUR3. A double mutant defective in both MUR3 （mur3.1） and XLT2 led to an Arabidopsis plant with xyloglucan that consists essentially of only xylosylated glucosyl units, with no further substitutions.A deep-sequencing approach was pursued utilizing 454 and Illumina sequencing methods to discover new genes involved in xyloglucan biosynthesis, cDNA sequences were generated from developing nasturtium （Tropaeolum majus） seeds, which produce large amounts of non-fucosylated xyloglucan as a seed storage polymer. In addition to known xyloglucan biosynthetic genes, a previously uncharacterized putative xyloglucan galactosyltransferase was iden- tified. Analysis of an Arabidopsis thaliana mutant line defective in the corresponding ortholog （AT5G62220） revealed that this gene shows no redundancy with the previously characterized xyloglucan galactosyltransferase, MUR3, but is required for galactosyl-substitution of xyloglucan at a different position. The gene was termed XLT2 for Xyloglucan L-side chain galactosylTransferase position 2. It represents an enzyme in the same subclade of glycosyltransferase family 47 as MUR3. A double mutant defective in both MUR3 （mur3.1） and XLT2 led to an Arabidopsis plant with xyloglucan that consists essentially of only xylosylated glucosyl units, with no further substitutions.

关 键 词：seed biology cell walls nasturtium storage polymers xyloglucan. 

分 类 号：S339.32[农业科学—作物遗传育种] Q26[农业科学—农艺学]