Switchgrass is native to the tallgrass prairie of North America. It is self-incompatible and has varied ploidy levels from diploid（2x） to dodecaploid（12x） with tetraploid and octoploid being the most common. The h...Switchgrass is native to the tallgrass prairie of North America. It is self-incompatible and has varied ploidy levels from diploid（2x） to dodecaploid（12x） with tetraploid and octoploid being the most common. The high yielding potential and the ability to grow well in marginal lands make switchgrass an ideal species as a dedicated biomass producer for lignocellulosic ethanol production. Genetic transformation is an important tool for studying gene function and for germplasm improvement in switchgrass, the genome of which has been sequenced recently. This paper intends to provide a comprehensive review on plant regeneration and genetic transformation in switchgrass. We first reviewed the effect of explants, basal medium and plant growth regulators on plant regeneration in switchgrass, which is a prerequisite for genetic transformation. We then reviewed the progresses on genetic transformation with either the biolistic or Agrobacterium-mediated method in switchgrass, and discussed various techniques employed to improve the transformation efficiency. Finally we reviewed the recent progresses on the use of genetic transformation in improving biomass quality such as the reduction of lignin, and in increasing biomass yield in switchgrass. We also provided a future perspective on the use of new genome editing technologies in switchgrass and its potential impact on regulatory processes.展开更多
Caffeic acid O-methyltransferase(COMT) is a crucial enzyme that mainly methylates phenylpropanoid meta-hydroxyl of C5 in the biosynthesis of syringyl lignin in angiosperms. A putative COMT, named as PvCOMT1,was isolat...Caffeic acid O-methyltransferase(COMT) is a crucial enzyme that mainly methylates phenylpropanoid meta-hydroxyl of C5 in the biosynthesis of syringyl lignin in angiosperms. A putative COMT, named as PvCOMT1,was isolated from switchgrass(Panicum virgatum), a C4 warm-season dual-purpose forage and bioenergy crop. Our results showed that recombinant PvCOMT1 enzyme protein catalyzed the methylation of 5-OH coniferyl alcohol, 5-OH coniferaldehyde(CAld5H) and 5-OH ferulic acid. Further in vitro studies indicate that CAld5H can dominate COMT-mediated reactions by inhibiting the methylation of the other substrates. Transgenic switchgrass plants generated by an RNAi approach were further employed to study the function of COMT in internode lignification. A dramatic decrease in syringyl lignin units coupled with an obvious incorporation in 5-OH guaiacyl lignin units were observed in the COMT-RNAi transgenic plants. However, the constitutive suppression of COMT in switchgrass plants altered neither the pattern of lignin deposition along the stem nor the anatomical structure of internodes. Consistent with the biochemical characterization of PvCOMT1, a significant decrease in sinapaldehyde was found in the COMT-RNAi transgenic switchgrass plants, suggesting that CAld5H could be the optimal intermediate in the biosynthesis syringyl lignin.展开更多
To date, most candidate systems for producing herbaceous cellulosic biomass have been composed of monocultures of perennial or annual grasses. Ecosystem goods and services provided from these biomass feedstock product...To date, most candidate systems for producing herbaceous cellulosic biomass have been composed of monocultures of perennial or annual grasses. Ecosystem goods and services provided from these biomass feedstock production systems could be increased dramatically with mixing of one or more forb species that would increase biodiversity and provide habitat for pollinators. Cup plant (Silphium perfoliatum L.) is featured with many desirable characteristics, such as high biomass potential, adaptation to marginal soils, and attractiveness to pollinators, desirable in a dicot species to grow in mixtures with perennial warm-season grasses. The objective of this study was to compare cup plant, switchgrass (Panicum virgatum L.), and prairie cordgrass (Spartina pectinata Link) monocultures to their mixtures for biomass production on prime and poorly drained marginal crop land for two years in both South Dakota and Wisconsin. In Wisconsin, monocultures of prairie cordgrass and cup plant and their mixture produced more biomass (8.1 Mg·ha-1) than the switchgrass monoculture and switchgrass/cup plant mixture (5.3 Mg·ha-1) on both prime and marginal land. While in South Dakota, drought and meristem destruction by the cup plant moth (Eucosma giganteana Riley) caused large reductions in biomass production (1.7 Mg·ha-1) in both years, with the switchgrass/cup plant mixture on marginal land having the highest yield (2.1 Mg·ha-1). Our study showed binary mixtures of cup plant and native warm-season grasses have great potential for increasing biodiversity and other ecosystem goods and services, relative to monocultures, for sustainable biomass feedstock production on poorly drained marginal land in the northcentral USA.展开更多
基金supported by a grant from the Bill Melinda Gates FoundationNational Institute of Food and Agriculture of the United States Department of Agriculture for support (Award number 2013-33522-21091)
文摘Switchgrass is native to the tallgrass prairie of North America. It is self-incompatible and has varied ploidy levels from diploid（2x） to dodecaploid（12x） with tetraploid and octoploid being the most common. The high yielding potential and the ability to grow well in marginal lands make switchgrass an ideal species as a dedicated biomass producer for lignocellulosic ethanol production. Genetic transformation is an important tool for studying gene function and for germplasm improvement in switchgrass, the genome of which has been sequenced recently. This paper intends to provide a comprehensive review on plant regeneration and genetic transformation in switchgrass. We first reviewed the effect of explants, basal medium and plant growth regulators on plant regeneration in switchgrass, which is a prerequisite for genetic transformation. We then reviewed the progresses on genetic transformation with either the biolistic or Agrobacterium-mediated method in switchgrass, and discussed various techniques employed to improve the transformation efficiency. Finally we reviewed the recent progresses on the use of genetic transformation in improving biomass quality such as the reduction of lignin, and in increasing biomass yield in switchgrass. We also provided a future perspective on the use of new genome editing technologies in switchgrass and its potential impact on regulatory processes.
基金supported by the "100-Talent Program of the Chinese Academy of Sciences" foundationthe National Natural Science Foundation of China (31470390)the National Key Technologies Research & Development Program-Seven Major Crop Breeding Project (2016YFD0101803)
文摘Caffeic acid O-methyltransferase(COMT) is a crucial enzyme that mainly methylates phenylpropanoid meta-hydroxyl of C5 in the biosynthesis of syringyl lignin in angiosperms. A putative COMT, named as PvCOMT1,was isolated from switchgrass(Panicum virgatum), a C4 warm-season dual-purpose forage and bioenergy crop. Our results showed that recombinant PvCOMT1 enzyme protein catalyzed the methylation of 5-OH coniferyl alcohol, 5-OH coniferaldehyde(CAld5H) and 5-OH ferulic acid. Further in vitro studies indicate that CAld5H can dominate COMT-mediated reactions by inhibiting the methylation of the other substrates. Transgenic switchgrass plants generated by an RNAi approach were further employed to study the function of COMT in internode lignification. A dramatic decrease in syringyl lignin units coupled with an obvious incorporation in 5-OH guaiacyl lignin units were observed in the COMT-RNAi transgenic plants. However, the constitutive suppression of COMT in switchgrass plants altered neither the pattern of lignin deposition along the stem nor the anatomical structure of internodes. Consistent with the biochemical characterization of PvCOMT1, a significant decrease in sinapaldehyde was found in the COMT-RNAi transgenic switchgrass plants, suggesting that CAld5H could be the optimal intermediate in the biosynthesis syringyl lignin.
文摘To date, most candidate systems for producing herbaceous cellulosic biomass have been composed of monocultures of perennial or annual grasses. Ecosystem goods and services provided from these biomass feedstock production systems could be increased dramatically with mixing of one or more forb species that would increase biodiversity and provide habitat for pollinators. Cup plant (Silphium perfoliatum L.) is featured with many desirable characteristics, such as high biomass potential, adaptation to marginal soils, and attractiveness to pollinators, desirable in a dicot species to grow in mixtures with perennial warm-season grasses. The objective of this study was to compare cup plant, switchgrass (Panicum virgatum L.), and prairie cordgrass (Spartina pectinata Link) monocultures to their mixtures for biomass production on prime and poorly drained marginal crop land for two years in both South Dakota and Wisconsin. In Wisconsin, monocultures of prairie cordgrass and cup plant and their mixture produced more biomass (8.1 Mg·ha-1) than the switchgrass monoculture and switchgrass/cup plant mixture (5.3 Mg·ha-1) on both prime and marginal land. While in South Dakota, drought and meristem destruction by the cup plant moth (Eucosma giganteana Riley) caused large reductions in biomass production (1.7 Mg·ha-1) in both years, with the switchgrass/cup plant mixture on marginal land having the highest yield (2.1 Mg·ha-1). Our study showed binary mixtures of cup plant and native warm-season grasses have great potential for increasing biodiversity and other ecosystem goods and services, relative to monocultures, for sustainable biomass feedstock production on poorly drained marginal land in the northcentral USA.
