Collaborative-RUI: CO2-Induced Changes in Heat-Shock Proteins and Photosynthetic Tolerance to Acute Heat Stress

项目层摘要-人类活动正在增加大气二氧化碳(CO2)水平。二氧化碳浓度升高会降低植物叶片中矿质营养物质和蛋白质的浓度，从而提高叶片温度。此外，二氧化碳的增加可能是最近全球气温上升的部分原因，预计本世纪全球气温将进一步上升。因此，在未来，植物，特别是树叶，将经历更高的温度。不幸的是，光合作用主要发生在叶片中，是对热胁迫最敏感的植物过程之一，因此热胁迫的增加将降低植物的生长和存活。然而，高二氧化碳对光合作用耐热胁迫的影响还不清楚。此外，高CO2对热休克蛋白(HSPs)产生的影响尚未被研究，但HSPs是几乎所有生物对热应激的主要适应，并且HSPs在热应激期间保护光合作用方面发挥着突出的作用。与大多数蛋白质一样，植物中热休克蛋白的产生受到细胞内矿质营养物质和总蛋白浓度的限制，热休克蛋白含量的任何下降都会削弱热休克蛋白对热胁迫期间光合作用的保护作用。因此，我们假设HSP的产生将在高CO2下减少，这将对植物和光合作用对热胁迫的耐受性产生负面影响。我们进一步假设，在不同种类的植物中，在不同的营养和生长温度条件下，热休克蛋白中高二氧化碳的减少将会有可预测的差异。我们将在这个研究项目中检验这些具体的假设。这项研究解决了当前对科学和社会都很重要的问题。该项目将增加对二氧化碳如何影响植物对高温胁迫耐受性的理解，这种情况在未来将变得更加常见(例如，人类驱动的二氧化碳增加将如何影响作物和本地植物的耐热性？不同类型的植物是否会受到相同程度的影响？对耐热性的不同影响是否有助于物种生存的变化，从而改变生物多样性？)这项研究也将有助于通过生物技术或育种提高作物的耐热性。这个项目是授予博士学位的研究人员和本科生机构的研究人员之间的合作。这两位主要研究人员都有将本科生、女性和少数族裔纳入他们的研究计划，并将NSF资助的研究融入他们的教学中的良好记录，这将继续进行拟议的项目。因此，该项目将在促进教学和培训的同时促进发现，并将增加代表不足的群体的参与。

PROJECT LAY SUMMARY- Human activities are increasing atmospheric carbon dioxide (CO2) levels. Elevated CO2 decreases the concentration of mineral nutrients and protein in plant leaves, and it increases leaf temperatures. Also, increases in CO2 may be partly responsible for recent increases in global temperatures, which are predicted to increase further in this century. Thus, in the future, plants, and particularly leaves, will experience higher temperatures. Unfortunately, photosynthesis, which occurs mostly in leaves, is among the most sensitive of plant processes to heat stress, so increases in heat stress will decrease plant growth and survival. However, the effects of high CO2 on the tolerance of photosynthesis to heat stress are not understood. Further, effects of high CO2 on production of heat-shock proteins (HSPs) have not been examined, yet HSPs are principle cellular adaptations to heat stress in nearly all organisms, and HSPs play prominent roles in protection of photosynthesis during heat stress. As with most proteins, HSP production in plants is limited by the cellular concentration of mineral nutrients and total protein, and any decreases in HSP content will decrease the protection of photosynthesis during heat stress by HSPs. Thus, we hypothesize that HSP production will decrease at high CO2, and this will negatively affect plant and photosynthetic tolerance to heat stress. We further hypothesize that high-CO2 decreases in HSPs will vary predictably among different categories of plants and under different nutrient and growth-temperature conditions. We will test these specific hypotheses in this research project. This research addresses problems that are currently important to both science and society. The project will increase the understanding of how CO2 affects plant tolerance to heat stress, which will become more common in the future (e.g., How will human-driven increases in CO2 affect the heat tolerance of crops and native vegetation? Will different types of plants be affected to the same extent? Will differential effects on thermotolerance contribute to changes in the survival of species, and hence biodiversity?). This research will also be useful in improving crop heat tolerance via biotechnology or breeding. This project is a collaboration between investigators at a Ph.D.-granting and an undergraduate institution. Both principal investigators have strong records of involving undergraduate students, women, and minorities in their research programs, and in integrating NSF-funded research into their teaching, and this will continue with the proposed project. Thus, this project will advance discovery while promoting teaching and training, and will increase participation of under-represented groups.