Modeling of plant responses to environmental stress based on gene expression information

本研究的目的是利用植物的基因表达信息和植物生理信息建立一个植物生长模型来评价植物对环境胁迫的响应。我们开发了一个生长室，能够在控制的环境条件下测量冠层的光合作用速率、蒸腾速率和臭氧气体吸收速率。为了分析水稻植株在不同臭氧浓度下的抗氧化酶基因如超氧化物歧化酶、过氧化氢酶和APX的基因表达水平以及光诱导基因的表达水平，我们还建立了实时荧光定量RT-PCR技术。这些治疗是41 ppb，每天7小时，74 ppb，每天12小时。抗氧化基因的mRNA水平在41 ppb时增加，但在74 ppb时下降。长期的实验表明，水稻植株在基因表达上有一个适应系统，以适应低臭氧浓度。接下来，水稻植株暴露在93,185和317 ppb的较高臭氧气体中6小时。在暴露6小时结束时，抗氧化基因的mRNA水平增加了93 ppb，并在暴露后保持较高水平，但在185 ppb和317 ppb的水平下降。在此基础上建立了水稻生长模型，用于预测水稻在环境胁迫条件下的生长变化。

The objective of this study was to develop a plant growth model to evaluate the responses to environmental stress using gene expression information and plant physiological information.We have developed a growth chamber, capable of measurement of canopy photosynthetic rate, transpiration rate and ozone gas absorption rate under controlled environment conditions. We also developed the technique of gene expression analysis using the real-time RT-PCR method in order to analyze mRNA levels of genes encoding antioxidant enzymes such SOD,CAT and APX and light induced genes of the rice plant under various ozone gas concentrations.Rice plants were exposed to low ozone gas concentrations for long periods. The treatments were 41 ppb for 7 hours a day and 74 ppb for 12 hours a day. The mRNA levels of antioxidant genes increased at 41 ppb, but decreased at 74 ppb. The long-term experiment showed that rice plant has an adaptation system in gene expression to get acclimatized to low ozone concentrations.Next, rice plants were exposed to higher ozone gas concentrations at 93,185 and 317 ppb for 6 hours. The mRNA levels of antioxidant genes increased at 93 ppb at the end of 6-h exposure and maintained higher levels after the exposure, but mRNA levels decreased at 185 and 317 ppb. From the result, limitation of ozone gas concentration for rice plants was considered between 100 and 200 ppb.Finally we developed a rice growth model based on a leaf growth model to predict changes of growth under environmental stress conditions.