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
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
The rhizosheath,a layer of soil grains that adheres firmly to roots,is beneficial for plant growth and adaptation to drought environments.Switchgrass is a perennial C4 grass which can form contact rhizosheath under dr...The rhizosheath,a layer of soil grains that adheres firmly to roots,is beneficial for plant growth and adaptation to drought environments.Switchgrass is a perennial C4 grass which can form contact rhizosheath under drought conditions.In this study,we characterized the microbiomes of four different rhizocompartments of two switchgrass ecotypes(Alamo and Kanlow)grown under drought or well-watered conditions via 16S ribosomal RNA amplicon sequencing.These four rhizocompartments,the bulk soil,rhizosheath soil,rhizoplane,and root endosphere,harbored both distinct and overlapping microbial communities.The root compartments(rhizoplane and root endosphere)displayed low-complexity communities dominated by Proteobacteria and Firmicutes.Compared to bulk soil,Cyanobacteria and Bacteroidetes were selectively enriched,while Proteobacteria and Firmicutes were selectively depleted,in rhizosheath soil.Taxa from Proteobacteria or Firmicutes were specifically selected in Alamo or Kanlow rhizosheath soil.Following drought stress,Citrobacter and Acinetobacter were further enriched in rhizosheath soil,suggesting that rhizosheath microbiome assembly is driven by drought stress.Additionally,the ecotype-specific recruitment of rhizosheath microbiome reveals their differences in drought stress responses.Collectively,these results shed light on rhizosheath microbiome recruitment in switchgrass and lay the foundation for the improvement of drought tolerance in switchgrass by regulating the rhizosheath microbiome.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.
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.
基金This work was supported by the Postdoctoral Science Foundation of China(2020M683593)the Chinese Universities Scientific Fund(2452019150)+4 种基金the Natural Science Foundation of Jiangsu Province(SBK2020042924)the Science Technology and Innovation Committee of Shenzhen(GJHZ20190821160401654)the National Natural Science Foundation of China(32061143023)Platform funding for Guangdong Provincial Enterprise Key Laboratory of Seed and Seedling Health Management Technology(2021B1212050011)the Hong Kong Research Grant Council(AoE/M-05/12,AoE/M-403/16,GRF14160516,14177617,12100318).
文摘The rhizosheath,a layer of soil grains that adheres firmly to roots,is beneficial for plant growth and adaptation to drought environments.Switchgrass is a perennial C4 grass which can form contact rhizosheath under drought conditions.In this study,we characterized the microbiomes of four different rhizocompartments of two switchgrass ecotypes(Alamo and Kanlow)grown under drought or well-watered conditions via 16S ribosomal RNA amplicon sequencing.These four rhizocompartments,the bulk soil,rhizosheath soil,rhizoplane,and root endosphere,harbored both distinct and overlapping microbial communities.The root compartments(rhizoplane and root endosphere)displayed low-complexity communities dominated by Proteobacteria and Firmicutes.Compared to bulk soil,Cyanobacteria and Bacteroidetes were selectively enriched,while Proteobacteria and Firmicutes were selectively depleted,in rhizosheath soil.Taxa from Proteobacteria or Firmicutes were specifically selected in Alamo or Kanlow rhizosheath soil.Following drought stress,Citrobacter and Acinetobacter were further enriched in rhizosheath soil,suggesting that rhizosheath microbiome assembly is driven by drought stress.Additionally,the ecotype-specific recruitment of rhizosheath microbiome reveals their differences in drought stress responses.Collectively,these results shed light on rhizosheath microbiome recruitment in switchgrass and lay the foundation for the improvement of drought tolerance in switchgrass by regulating the rhizosheath microbiome.
