De novo Characterization of the Platycladus orientalis Transcriptome and Analysis of Photosynthesis-Related Genes during Aging

Journal Article · 03 May 2019 · Forests

DOI: https://doi.org/10.3390/f10050393 · OSTI ID:1511917

Chang, Ermei ^[1]; Zhang, Jin  ^[2]; Yao, Xiamei ^[3]; Tang, Shuo ^[4]; Zhao, Xiulian ^[5]; Deng, Nan ^[5]; Shi, Shengqing ^[5]; Liu, Jianfeng ^[5]; Jiang, Zeping ^[6]

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1. Chinese Academy of Forestry, Beijing (China). State Key Lab. of Tree Genetics and Breeding, Key Lab. of Tree Breeding and Cultivation of National Forestry and Grassland Administration, Research Inst. of Forestry
2. Chinese Academy of Forestry, Beijing (China). State Key Lab. of Tree Genetics and Breeding, Key Lab. of Tree Breeding and Cultivation of National Forestry and Grassland Administration, Research Inst. of Forestry; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biosciences Division
3. Fuyang Normal Univ., Fuyang (China)
4. Zhongshan Park, Beijing (China)
5. Chinese Academy of Forestry, Beijing (China). State Key Lab. of Tree Genetics and Breeding, Key Lab. of Tree Breeding and Cultivation of National Forestry and Grassland Administration, Research Inst. of Forestry
6. Chinese Academy of Forestry, Beijing (China). State Key Lab. of Tree Genetics and Breeding, Key Lab. of Tree Breeding and Cultivation of National Forestry and Grassland Administration, Research Inst. of Forestry, and Research Inst. of Forest Ecology, Environment and Protection

In China, Platycladus orientalis has a lifespan of thousands of years. The long lifespan of these trees may be relevant for the characterization of plant aging at the molecular level. However, the molecular mechanism of the aging process of P. orientalis is still unknown. To explore the relationship between age and growth of P. orientalis, we analyzed physiological changes during P. orientalis senescence. The malondialdehyde content was greater in 200-, 700-, and 1100-year-old ancient trees than in 20-year-old trees, whereas the peroxidase and superoxide dismutase activities, as well as the soluble protein content, exhibited the opposite trend. Furthermore, we performed a de novo transcriptome assembly using RNA-Seq and obtained 48,044 unigenes with an average length of 896 bp. A total of 418 differentially expressed genes were identified in different stages of aging of P. orientalis. Clustering analysis revealed distinct timepoints at which the oxidation–reduction and photosynthesis pathways changed. Eight clusters with distinct expression patterns were identified. The expression levels of photosynthesis-, oxidation–reduction-, and transporter-related genes were down-regulated, whereas those of transcription-, signaling-, and senescence-related genes were up-regulated during aging. In addition, consistent with the most obviously down-regulated genes of photosynthesis-related genes, the photosynthetic indexes including chlorophyll a and b levels decreased steadily during P. orientalis aging. This study combined transcriptome with physiological and biochemical data, revealing potential candidate genes influencing senescence during P. orientalis aging.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1511917
• Journal Information: Forests, Vol. 10, Issue 5; ISSN 1999-4907
• Publisher: MDPICopyright Statement
• Country of Publication: United States
• Language: English