Improving stress tolerance in the bioenergy crop switchgrass (Panicum virgatum) by investigating and engineering terpene metabolic networks

禾本科作物柳枝稷（柳枝稷）作为下一代木质纤维素生物燃料生产的专用原料具有农业经济价值。高净能量产量和广泛的栖息地范围使柳枝稷适合在减少农业投入的边缘土地上种植，有望实现可持续的生物燃料生产。然而，日益严重的干旱和其他环境压力预计将成为扩大柳枝稷种植的主要障碍。更深入地了解柳枝稷环境适应的分子机制将为优化作物生产力提供关键资源。物种特异性萜烯的动态网络是柳枝稷非生物胁迫耐受性的关键组成部分，这方面的知识可以通过精确的基因组工程来利用，以产生更耐胁迫的作物，并提供先进的生物燃料生产。利用基因组学平台快速发现萜烯代谢网络，已在柳枝稷中鉴定出大型且功能多样的萜烯代谢基因家族。初步研究进一步证明了压力引起的萜烯途径的上调，支持柳枝稷应激防御的作用。利用这些结果，该项目将全基因组酶发现与全系统组学，机制和生物活性研究相结合，以确定柳枝稷萜烯代谢的生物合成网络和保护作用。这一见解可以促进靶向基因组工程，设计具有定制萜烯混合物的植物，以增强生物质原料的弹性和生物燃料生产。

The Poaceous crop switchgrass (Panicum virgatum) is of agroeconomic value as a dedicated next-generation feedstock for lignocellulosic biofuel production. High net energy yield and a wide habitat range make switchgrass suitable for cultivation on marginal lands with reduced agricultural inputs, promising sustainable biofuel production. However, rising drought and other environmental pressures are projected to become major impediments for expanded switchgrass cultivation. A deeper knowledge of the molecular mechanisms that govern switchgrass environmental adaptation would offer critical resources for optimizing crop productivity. Dynamic networks of species-specific terpenes serve as key components of switchgrass abiotic stress tolerance, knowledge of which can be harnessed through precision genome engineering to generate crops that are more resistant to stress and provide advanced biofuel production. Using a genomics-enabled platform for the rapid discovery of terpene metabolic networks, large and functionally diverse terpene-metabolic gene families have been identified in switchgrass. Preliminary studies further demonstrated stress-elicited up-regulation of terpene pathways, supporting a role in switchgrass stress defenses. Leveraging these results, this project merges genome-wide enzyme discovery with system-wide omics, mechanistic and bioactivity studies to define the biosynthetic network and protective roles of switchgrass terpene metabolism. This insight can facilitate targeted genome engineering to design plants with tailored terpene blends for enhanced resilience and biofuel production from biomass feedstock.