Background

The amount of fluoride accumulation in tea leaves was gradually increase as the matures of tea plants, and the excessive fluoride intake can threaten people's health. Based on years of field investigations, a low level of fluoride variety Xiangbo Lǜ (XBL) and a high level of fluoride variety Zhenong 139 (ZN139) were selected.

Results

In this study, the root, 1st and the 5th leaf of the two-year-old tea trees were used for morphological, physiological and comparative transcriptomics analysis to understand the different features of “XBL” and “ZN139” under fluoride stress conditions. The color of the 1st and 5th leaves of XBL were yellower, the activity of peroxidase, catalase and antioxidant enzyme were lower than ZN139 under the high-fluoride stress. Transcriptomics analysis indicated that core genes involved in photosynthesis rates regulation showed no significantly exchanged expression, the co-downregulation of magnesium ions transportation, while the ROS scavenging, vegetative growth and self-compatibility between the two varieties were different. Crucial genes' expression were also identified by the real-time RT-PCR.

Conclusion

The tea tree is one of the few plants that has a high-fluoride content, but the different varieties respond differently to fluoride stress. High-fluoride tea tree varieties, such as ZN139, have stronger ROS scavenging abilities through the use of both their non-enzymatic and enzymatic antioxidant systems which act by increasing the expression levels of inositol-1-monophosphatases and peroxidases, among others. ZN139 can also compensate for the decrease in photosynthetic rate that is associated with the ionic imbalance caused by the reduced consumption of light energy during long-periods of high fluoride stress. Reproductive development was protected in ZN139 by the up-regulated expression of S-locus glycoprotein, Mildew resistance locus o and Phospholipase D under fluoride stress, while the vegetative development of low-fluoride varieties such as XBL was retarded. More starch and cellulose were redistributed to glucose by increasing the expression levels of glycosyl transferases and hydrolases to provide more energy for processes involved in the response and tolerance towards fluoride stress.

中文翻译：

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不同茶叶品种对不同氟化物浓度胁迫的营养生长和生殖生长的比较研究。

背景

随着茶树的成熟，茶叶中的氟化物积累量逐渐增加，过量摄入的氟化物会威胁人们的健康。根据多年的现场调查，选择了低含量的氟品种香博Lǜ（XBL）和高含量的氟品种珍农139（ZN139）。

结果

在这项研究中，使用两年生茶树的根，第一叶和第五叶进行形态，生理和比较转录组学分析，以了解在氟胁迫条件下“ XBL”和“ ZN139”的不同特征。在高氟胁迫下，XBL的第1和第5叶片颜色偏黄，过氧化物酶，过氧化氢酶和抗氧化酶的活性低于ZN139。转录组学分析表明，参与光合作用速率调节的核心基因没有显着交换表达，没有共同下调镁离子的转运，而两个品种之间的ROS清除，营养生长和自溶性却不同。还通过实时RT-PCR鉴定了关键基因的表达。

结论

茶树是少数具有高氟化物含量的植物之一，但是不同的品种对氟化物胁迫的反应不同。高氟化物茶树品种（例如ZN139）通过使用其非酶促和酶促抗氧化剂系统具有更强的ROS清除能力，这些系统通过提高肌醇-1-单磷酸酶和过氧化物酶的表达水平发挥作用。ZN139还可以补偿光合速率的下降，该下降是由于在高氟化物应力的长期状态下光能消耗减少而导致的离子不平衡所致。S-基因座糖蛋白，霉菌抗性基因座o和磷脂酶D的表达上调保护了ZN139的生殖发育在氟胁迫下，低氟品种（如XBL）的营养发育受到阻碍。通过增加糖基转移酶和水解酶的表达水平，更多的淀粉和纤维素被重新分配给葡萄糖，从而为参与氟化物胁迫响应和耐受的过程提供更多能量。