Chinese Bulletin of Botany ›› 2020, Vol. 55 ›› Issue (6): 677-692.DOI: 10.11983/CBB20048

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Effects of Epigenetic Mechanisms on C4 Phosphoenolpyruvate Carboxylase Transgenic Rice (Oryza sativa) Seed Germination Under Drought Stress

Ningxi Song1,2, Yingfeng Xie2, Xia Li1,2,3,*   

  1. 1Nanjing Branch of China National Center for Rice Improvement/Jiangsu High Quality Rice Engineering Technology Research Center/Institute of Food Crops, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
    2College of Biology and Environment, Nanjing Forestry University, Nanjing 210037, China
    3Collaborative Innovation Center for Modern Production Technology of Grain Crops of Jiangsu Province, Agricultural College, Yangzhou University, Yangzhou 225009, China
  • Received:2020-03-21 Accepted:2020-08-26 Online:2020-11-01 Published:2020-11-11
  • Contact: Xia Li

Abstract: In order to reveal the effect of epigenetic mechanism under drought stress toward seed germination of transgenic rice within high maize C4-type PEPC gene expressing, C4-PEPC transgenic rice (PC) and wild type rice Kitaake (WT) were used in this study. By introducing DNA methylation inhibitor (5-azacytidine, 5azaC) and alternative splicing inhibitors (macrolides pladienolide B, PB), the drought simulation treatments with 10% (m/v) polyethylene glycol-6000 (PEG6000) alone or combining with the inhibitors were used for seed germination experiments. Seed vigor, soluble sugar and soluble protein content, α-amylase activity and the expression levels of related genes, PEPC-related genes, sugar signal-related genes, and some splicing factor genes during germination were measured. In the results, when treated with 0.25 µmol·L-1, PB had showed a significant inhibitory effect on the seed germination of the two tested rice lines under drought conditions. The content of total soluble sugar, sucrose, glucose, fructose and soluble protein during seed germination after PB addition was reduced to a certain extent under drought conditions. PB treatment also inhibited the gene expression of sucrose nonfermenting-1 (SNF1)-related protein kinase SnRKs family and the splicing factor arginine/serine-rich proteins (SR proteins), and the activity of α-amylase as well, but the inhibitory effect on PC is less than those on WT. 5 µmol·L -1 5azaC treatment had an opposite effect with alternative splicing inhibitors. The combination treatment with 5azaC and PEG6000 partially alleviated the inhibitory effect of drought stress on rice seed germination, and the germination rate of the tested materials increased. It can be seen that the mechanism of DNA methylation and alternative splicing are involved in drought tolerance at the bud stage of rice lines, with a larger effect on PC.

Key words: alternative splicing, DNA methylation, drought stress, germination, PEPC gene, rice (Oryza sativa)