Buell C Robin, Dardick Christopher, Parrott Wayne, Schmitz Robert J, Shih Patrick M, Tsai Chung-Jui, Urbanowicz Breeanna
Center for Applied Genetic Technologies, Institute of Plant Breeding, Genetics, and Genomics, Department of Crop and Soil Sciences, University of Georgia, Athens, GA, United States.
Agricultural Research Service, U.S. Department of Agriculture, Kearneysville, WV, United States.
Front Plant Sci. 2023 Oct 30;14:1288826. doi: 10.3389/fpls.2023.1288826. eCollection 2023.
Humans have been modifying plant traits for thousands of years, first through selection (i.e., domestication) then modern breeding, and in the last 30 years, through biotechnology. These modifications have resulted in increased yield, more efficient agronomic practices, and enhanced quality traits. Precision knowledge of gene regulation and function through high-resolution single-cell omics technologies, coupled with the ability to engineer plant genomes at the DNA sequence, chromatin accessibility, and gene expression levels, can enable engineering of complex and complementary traits at the biosystem level. spp., the primary genetic model system for woody perennials, are among the fastest growing trees in temperate zones and are important for both carbon sequestration and global carbon cycling. Ample genomic and transcriptomic resources for poplar are available including emerging single-cell omics datasets. To expand use of poplar outside of valorization of woody biomass, chassis with novel morphotypes in which stem branching and tree height are modified can be fabricated thereby leading to trees with altered leaf to wood ratios. These morphotypes can then be engineered into customized chemotypes that produce high value biofuels, bioproducts, and biomaterials not only in specific organs but also in a cell-type-specific manner. For example, the recent discovery of triterpene production in poplar leaf trichomes can be exploited using cell-type specific regulatory sequences to synthesize high value terpenes such as the jet fuel precursor bisabolene specifically in the trichomes. By spatially and temporally controlling expression, not only can pools of abundant precursors be exploited but engineered molecules can be sequestered in discrete cell structures in the leaf. The structural diversity of the hemicellulose xylan is a barrier to fully utilizing lignocellulose in biomaterial production and by leveraging cell-type-specific omics data, cell wall composition can be modified in a tailored and targeted specific manner to generate poplar wood with novel chemical features that are amenable for processing or advanced manufacturing. Precision engineering poplar as a multi-purpose sustainable feedstock highlights how genome engineering can be used to re-imagine a crop species.
数千年来，人类一直在改变植物性状，最初是通过选择（即驯化），然后是现代育种，在过去30年里，则是通过生物技术。这些改良带来了产量的提高、更高效的农艺实践以及品质性状的增强。通过高分辨率单细胞组学技术精确了解基因调控和功能，再加上在DNA序列、染色质可及性和基因表达水平上对植物基因组进行工程改造的能力，能够在生物系统层面实现复杂互补性状的工程改造。杨树作为木本多年生植物的主要遗传模型系统，是温带地区生长最快的树木之一，对碳固存和全球碳循环都很重要。杨树有丰富的基因组和转录组资源，包括新出现的单细胞组学数据集。为了扩大杨树在木质生物质增值利用之外的用途，可以构建具有新型形态类型的底盘，改变其茎分枝和树高，从而培育出叶木比改变的树木。然后可以将这些形态类型设计成定制的化学类型，不仅能在特定器官中，还能以细胞类型特异性的方式生产高价值生物燃料、生物产品和生物材料。例如，利用细胞类型特异性调控序列，可以开发杨树叶片毛状体中三萜类化合物的生产，从而在毛状体中特异性合成高价值萜类化合物，如喷气燃料前体红没药烯。通过时空控制表达，不仅可以利用大量前体库，还可以将工程分子隔离在叶片中的离散细胞结构中。半纤维素木聚糖的结构多样性是生物材料生产中充分利用木质纤维素的障碍，利用细胞类型特异性组学数据，可以以定制和靶向的特定方式改变细胞壁组成，从而培育出具有适合加工或先进制造的新型化学特性的杨树木材。将杨树精准工程改造为多用途可持续原料，凸显了基因组工程如何能够用于重新构想一种作物。
