Genetic modification of plant cell walls to enhance biomass yield and biofuel production in bioenergy crops.
Plant cell walls represent an enormous biomass resource for the generation of biofuels and chemicals. As lignocellulose property principally determines biomass recalcitrance, the genetic modification of plant cell walls has been posed as a powerful solution. Here, we review recent progress in understanding the effects of distinct cell wall polymers (cellulose, hemicelluloses, lignin, pectin, wall proteins) on the enzymatic digestibility of biomass under various physical and chemical pretreatments in herbaceous grasses, major agronomic crops and fast-growing trees. We also compare the main factors of wall polymer features, including cellulose crystallinity (CrI), hemicellulosic Xyl/Ara ratio, monolignol proportion and uronic acid level. Furthermore, the review presents the main gene candidates, such as CesA, GH9, GH10, GT61, GT43 etc., for potential genetic cell wall modification towards enhancing both biomass yield and enzymatic saccharification in genetic mutants and transgenic plants. Regarding cell wall modification, it proposes a novel groove-like cell wall model that highlights to increase amorphous regions (density and depth) of the native cellulose microfibrils, providing a general strategy for bioenergy crop breeding and biofuel processing technology.
Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan 430070, China; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Yanting
Y
Wang
Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan 430070, China; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Chunfen
C
Fan
Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan 430070, China; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Huizhen
H
Hu
Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan 430070, China; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Ying
Y
Li
Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan 430070, China; College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; College of Chemistry and Chemical Engineering, Hubei University of Technology, Wuhan, Hubei 430068, China.
Dan
D
Sun
Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan 430070, China; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Youmei
Y
Wang
Biomass and Bioenergy Research Centre, Huazhong Agricultural University, Wuhan 430070, China; National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China. Electronic address: lpeng@mail.hzau.edu.cn.
Liangcai
L
Peng
D056804:Biofuels; D018533:Biomass; D001709:Biotechnology; D002473:Cell Wall; D002482:Cellulose; D018556:Crops, Agricultural; D059828:Plant Cells; D030821:Plants, Genetically Modified
D056804:Biofuels; D002482:Cellulose
Bioenergy crops; Biomass pretreatment; Biomass yield; Enzymatic digestibility; Genetic manipulation; Lignocellulose features; Lodging resistance; Plant cell walls; Yeast fermentation