title: Overexpression of the WOX gene STENOFOLIA improves biomass yield and sugar release in transgenic grasses and display altered cytokinin homeostasis.
abstract: Lignocellulosic biomass can be a significant source of renewable clean energy with continued improvement in biomass yield and bioconversion strategies. In higher plants, the leaf blade is the central energy convertor where solar energy and CO2 are assimilated to make the building blocks for biomass production. Here we report that introducing the leaf blade development regulator STENOFOLIA (STF), a WOX family transcription factor, into the biofuel crop switchgrass, significantly improves both biomass yield and sugar release. We found that STF overexpressing switchgrass plants produced approximately 2-fold more dry biomass and release approximately 1.8-fold more solubilized sugars without pretreatment compared to controls. The biomass increase was attributed mainly to increased leaf width and stem thickness, which was also consistent in STF transgenic rice and Brachypodium, and appeared to be caused by enhanced cell proliferation. STF directly binds to multiple regions in the promoters of some cytokinin oxidase/dehydrogenase (CKX) genes and represses their expression in all three transgenic grasses. This repression was accompanied by a significant increase in active cytokinin content in transgenic rice leaves, suggesting that the increase in biomass productivity and sugar release could at least in part be associated with improved cytokinin levels caused by repression of cytokinin degrading enzymes. Our study provides a new tool for improving biomass feedstock yield in bioenergy crops, and uncovers a novel mechanistic insight in the function of STF, which may also apply to other repressive WOX genes that are master regulators of several key plant developmental programs.
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China.|Department of Plant and Soil Sciences, Institute for Agricultural Biosciences, Oklahoma State University, 3210 Sam Noble Parkway, Ardmore, OK, United States of America.
authors.forename: Lifang
authors.initials: L
authors.lastname: Niu
authors.affiliation: Forage Improvement Division, Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, United States of America.
authors.forename: Chunxiang
authors.initials: C
authors.lastname: Fu
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Meng
authors.affiliation: Department of Plant and Soil Sciences, Institute for Agricultural Biosciences, Oklahoma State University, 3210 Sam Noble Parkway, Ardmore, OK, United States of America.
authors.forename: Dajun
authors.initials: D
authors.lastname: Sang
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Pengcheng
authors.initials: P
authors.lastname: Yin
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Jinxia
authors.initials: J
authors.lastname: Wu
authors.affiliation: Plant Biology Division, Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, United States of America.
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Tiegang
authors.initials: T
authors.lastname: Lu
authors.affiliation: Forage Improvement Division, Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK, United States of America.
authors.forename: Zeng-Yu
authors.initials: ZY
authors.lastname: Wang
authors.affiliation: Department of Plant and Soil Sciences, Institute for Agricultural Biosciences, Oklahoma State University, 3210 Sam Noble Parkway, Ardmore, OK, United States of America.
authors.forename: Million
authors.initials: M
authors.lastname: Tadege
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China.|Department of Plant and Soil Sciences, Institute for Agricultural Biosciences, Oklahoma State University, 3210 Sam Noble Parkway, Ardmore, OK, United States of America.
authors.forename: Hao
authors.identifier: 0000-0003-4717-8335
authors.initials: H
authors.lastname: Lin
mesh_terms: D056804:Biofuels; D018533:Biomass; D058431:Brachypodium / Q000235:genetics / Q000378:metabolism; D050260:Carbohydrate Metabolism; D049109:Cell Proliferation; D047369:Chromatin Immunoprecipitation; D018556:Crops, Agricultural / Q000235:genetics / Q000378:metabolism; D003583:Cytokinins / Q000235:genetics* / Q000378:metabolism; D018744:DNA, Plant / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006706:Homeostasis; D046913:Medicago truncatula / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000235:genetics / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics; D008897:Panicum / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D018515:Plant Leaves / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D019076:Transgenes
chemical_list: D056804:Biofuels; D003583:Cytokinins; D018744:DNA, Plant; D010940:Plant Proteins; D014157:Transcription Factors; D049452:Green Fluorescent Proteins; D010088:Oxidoreductases; C019984:cytokinin oxidase