Biomechanical Properties of Bioenergy Sorghum: Changes in Gene Expression Due to Mechanical Stimulation

生物能源高粱是一种相对较新的高粱，由于其大量的生物质，已成为生物燃料的潜在来源。这种高粱长得相对较高（3-5米），但通常会在风、雨、冰雹或其他机械压力下折断和倾倒。一个有希望的减少破碎的方法是开发新的机械坚固的高粱品种。 要做到这一点，需要对秸秆的生物力学特性有基本的了解，并确定产生更强壮植物的遗传和环境影响。实验表明，在植物生长期间机械刺激可以显著改变高粱茎的物理和生物力学特性。 这是因为机械负荷改变了植物茎中细胞的生长。这种机械刺激导致适应性生长，改善了茎的机械性能。这项研究将加速开发新的燃料丰富和机械耐用的高粱品种，从而导致粮食，饲料和生物质生产力的显着增加。该项目将为本科生和研究生提供跨学科的专业和技术培训。 该团队还将参加教师暑期研究体验（RET）计划和夏令营，向高中教师和学生传播高粱的生物力学和遗传学/表观遗传学研究。为了实现这些目标，本研究将整合生物能源高粱秸秆的结构形态，生物力学特性，生理学和遗传学/表观遗传学的实验和计算研究，为高粱茎秆倒伏（折断）提供理论依据，指导抗倒伏高粱新品种的选育。这项工作的智力意义在于解决以下基本问题：1）揭示thigmomorphogenic反应（对机械刺激的反应）调节生物能源高粱秸秆的生物力学性能，包括研究与秸秆机械性能相关的表观遗传变化，基因表达和激素反应; 2）揭示秸秆及其组分的粘弹性响应的影响细胞壁结构不同的厚壁组织和薄壁组织对茎倒伏的影响;和3）为具有上级生物力学性质的茎提供结构-性质-遗传/表观遗传关系。从这项研究中获得的知识可能会转移到其他草，从而扩大该项目的影响。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估的支持。

Bioenergy sorghum, a relatively new type of sorghum, has emerged as a potential source for biofuel owing to its large amount of biomass. This sorghum grows relatively tall (3-5 m) but commonly breaks and topples under wind, rain, hail or other mechanical stresses. A promising approach to reduce breakage is to develop new mechanically robust sorghum varieties. To do this will require a fundamental understanding of the biomechanical properties of stalks and identifying the genetic and environmental influences that produce stronger plants. Experiments have shown that mechanically stimulating the plants during growth can significantly change the physical and biomechanical characteristics of sorghum stems. This occurs because the mechanical load changes the growth of the cells in the plant stem. This mechanical stimulation causes adaptive growth that improves the mechanical properties of the stalk. This research will accelerate the development of new fuel-rich and mechanically robust varieties of sorghum, thereby leading to significant increases in food, feed, and biomass productivity. This project will provide undergraduate and graduate students with interdisciplinary professional and technical training. The team will also participate in a summer research experience for teacher (RET) program and summer camps to disseminate the study of biomechanics and genetics/epigenetics of sorghum to high school teachers and students.To accomplish these goals, this study will integrate experimental and computational studies of structural morphologies, biomechanical properties, physiology, and genetics/epigenetics of bioenergy sorghum stalks, to provide a fundamental explanation of stalk lodging (breaking) and to guide development of new lodging-resistant sorghum. The intellectual significance of this work resides in addressing the following fundamental topics: 1) uncovering the thigmomorphogenic response (response to mechanical stimulation) in tuning the biomechanical properties of bioenergy sorghum stalks, including investigating epigenetic changes, gene expression, and hormonal responses associated with the mechanical properties of stalks; 2) revealing the impact of the viscoelastic responses of stalks and their constituents (sclerenchymatous tissue and parenchymatous tissue with different cell wall structures) on stem lodging; and 3) providing structure-property-genetic/epigenetic relationships for stalks with superior biomechanical properties. Knowledge gained from this study will likely be transferable to other grasses, thereby extending the impact of the project.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.