彩叶植物叶片花色素苷代谢与臭氧敏感性的相关性及其调控机理

Tropospheric ozone is an important air pollutant which can cause the haze weather. High ozone concentration has seriously negative effects on people’s health and the growth and development of plants. The color-leafed plants have certain resistance to ozone, however, the response mechanisms of anthocyanin biosynthesis in leaves of color-leafed plants to ozone stress has not been reported.. We will select red-leaf and green-leaf cultivars from color-leafed plant species as materials. The open top chambers (OTCs) will be used to simulate the acute and chronic ozone pollution. visible leaf injuries and biomass changes will be considered as indicators of the ozone sensitivities. Anthocyanin distribution will be observed through cross-section, total anthocyanin content and components will be measured. The relationship between anthocyanin metabolism and plant sensitivity will be discussed. The generation of reactive oxygen species (ROS) in leaf will be observed under microscope by DAB and NBT staining. The activity and quantity of ROS，antioxidative enzymes and low-molecular weight antioxidants will be measured. The relationship between anthocyanthin and ROS will be studied. Gas exchange parameters and chlorophyll fluorescence parameters will be measured to reveal responses of carbon assimilation and photosystem II to anthocyanin metabolism under ozone pollution. The expression of structural genes and regulatory genes involved in anthocyanin biosynthesis will be examined between the red-leaf and green-leaf cultivars by RNA sequencing technique and the real-time fluorescent quantitative RT-PCR. The response mechanisms of anthocyanin metabolism in leaves of color-leafed plants to ozone pollution will be revealed. Results of this program will provide theoretical basis for plant arrangment and plant genetic improvement under high ozone-polluted district.

臭氧是重要的空气污染物，也是雾霾形成的主因之一。高浓度臭氧严重危害人体健康及植物的生长发育。彩叶植物具有一定的臭氧抗性，但彩叶植物叶片花色素苷代谢对臭氧胁迫的响应机理尚不明确。为了探明该机制，本研究拟选用彩叶植物红叶和绿叶品种为试材，通过人工模拟急性和慢性臭氧污染，观察叶片可见伤害及生物量变化，以评价其臭氧敏感性差异；进一步测定其花色素苷含量及组分，进行组织化学定位，探讨花色素苷代谢与臭氧敏感性的相关性；并观察活性氧分子的代谢与花色素苷代谢的关系；以及臭氧胁迫下花色素苷代谢对光合电子传递以及碳同化的影响；在此基础上进一步通过转录组测序，结合实时荧光定量RT-PCR技术，明确臭氧胁迫下不同叶色品种基因表达差异以及花色素苷合成关键酶基因及调控基因的表达特征，揭示彩叶植物叶片花色素苷代谢在臭氧胁迫下的应答机制。为应对臭氧浓度升高的园林植物配置和植物遗传改良提供理论依据。

对流层臭氧（O3）是一种重要的空气污染物, 会对人类和动物健康以及农林业生产活动造成严重危害。很多研究表明，臭氧污染下的植物叶片能形成花色素苷。因此，我们推测活体中的花色素苷或许具有清除活性氧的能力，叶片中富含花色素苷的植物品种或许具有更高的臭氧抗性。. 本项目利用开顶式同化箱，以观叶植物——彩叶草、四季秋海棠、小白菜的不同叶色品种为对象，通过可见伤害观察，探明不同叶色品种对O3污染的敏感性差异，通过测定植物叶片活性氧代谢、抗氧化酶活性和抗氧化剂含量、叶片气体交换、叶绿素荧光参数等生理生化指标来揭示不同叶色彩叶草、四季秋海棠、小白菜品种对O3污染敏感性差异的生理生化机理，并通过转录组测序、荧光定量PCR等方式找到影响植物臭氧敏感性的功能基因。. 本研究首次明确了不同叶色小白菜的臭氧敏感性差异及内在机理，发现花色素苷通过保护光系统II的功能和活性，缓解光抑制对净光合速率的影响，提高植物碳同化能力，进而提高臭氧抗性。比较了彩叶草、四季秋海棠不同叶色品种的臭氧敏感性差异，发现红铜色四季秋海棠的臭氧抗性高于绿叶品种，而晚霞色（红色）彩叶草品种的臭氧敏感性高于凤梨色（黄绿色）品种。通过转录组测序，比较了绿叶和紫叶小白菜的基因表达，找到了2475个差异基因，KEGG富集在类黄酮合成途径上，紫叶品种中PAL, C4H3, FLS, DFR, ANS等基因表达上调，而MYBL2可能发挥关键的调控作用。首次比较了不同臭氧浓度下叶菜类蔬菜-小白菜的转录谱，发现谷胱甘肽代谢途径在臭氧响应上发挥着重要的作用，而AP2/ERFP, WRKY, JAZ, MYB家族的转录因子发挥了重要的调控作用。. 本研究的结果为为城市绿化植物的选择和高O3污染下园林植物的抗性育种提供了理论基础。