JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2023, Vol. 47 ›› Issue (6): 35-41.doi: 10.12302/j.issn.1000-2006.202209026

Special Issue: “攥紧中国种子”视域下的中国林草种业研究专题Ⅱ

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Effects of BR on enzyme activities related to fatty acid synthesis and oil accumulation of Styrax tonkinensis seeds

CHEN Junna1(), WANG Xiaoyu1, CHEN Chen1, PENG Huiwu2, CHEN Juan2, HUANG Weihe2, YU Fangyuan1,*()   

  1. 1. College of Forestry and Grassland, Nanjing Forestry University, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing 210037, China
    2. Pingxiang Institute of Forestry, Jiangxi Province, Pingxiang 337000, China
  • Received:2022-09-13 Revised:2022-10-13 Online:2023-11-30 Published:2023-11-23

Abstract:

【Objective】The study explored the effects of brassinolide (BR) on enzyme activities related to fatty acid synthesis and oil accumulation in seeds of Styrax tonkinensis. The aim was to provide theoretical and practical data for studies of the mechanism by which exogenous BR promotes fatty acid synthesis and oil accumulation in seeds of S. tonkinensis. 【Method】Ten-year-old seed trees of S. tonkinensis were sprayed with four different concentrations of brassinolide solution: 1(BR 1), 5(BR 5), 10(BR 10) and 20(BR 20) μmol/L, with distilled water sprayed as the control. The different BR concentrations were sprayed 45, 65, 95 and 125 d after flowering. Fruit samples were collected 50, 70, 100 and 130 d after flowering. The activities of fatty acid synthase (FAS), 1-aminocyclopropane-1-carboxylate (ACC) and diacylglycerol acyltransferase (DGAT) were measured during seed development. Fruit fresh weight and seed crude fat mass fraction were also determined. The effects of different concentrations of BR on enzyme activities related to fatty acid synthesis in S. tonkinensis seeds were analyzed. 【Result】BR treatment had significant effects on the activities of enzymes related to fatty acid synthesis during the seed development of S. tonkinensis. FAS activity was low at 50 d after flowering, increased, significantly and peaked at 100 d after flowering, and then decreased slowly. At 100 d after flowering, the activity of FAS in the BR5 and BR10 treatments reached the maximum value at the same time. The respective values of 329.104 and 326.744 nmol/(min·mg) exceeded the control value by 1.8 times. The ACC activity of S. tonkinensis seeds increased, then decreased, then increased again. At 70 d after flowering, the ACC activity in the BR5 treatment peaked 20.50 nmol/mg, which was 5.9 times that of the control group. The activity of DGAT in the different treatments first increased and then decreased, reaching a peak at 100 d after flowering. The activity of DGAT in each BR treatment group was significantly higher than that in the control group. DGAT activity in the BR5 treatment was highest at 6.03 nmol/mg, which was 1.2 times of that the control group. BR promoted the activities of FAS, ACC and DGAT in S. tonkinensis seeds, with the most significant effect with the BR5 treatment. During the four periods of time, the medium concentration of BR treatment improved the crude fat fraction of S. tonkinensis seeds. Seventy days after flowering, there were significant differences in the seed crude fat mass fraction under different treatments, and that of the BR5 treatment was significantly higher than that of the other treatments. The fresh weight of S. tonkinensis fruits increased after treatment with different concentrations of BR. The BR5 treatment had the greatest effect on fruit fresh weight, except at 100 d after flowering. There was a significant positive correlation between enzyme activities related to fatty acid synthesis and both seed crude fat mass fraction and fruit fresh weight. 【Conclusion】 The dynamic changes in FAS, ACC and DGAT activities showed that BR treatment increased the activities of enzymes related to fatty acid synthesis and promoted fatty acid synthesis during seed development. The BR5 treatment had the best effect. BR treatment also increased fruit fresh weight and seed crude fat fraction. Correlation analysis showed that the activities of enzymes related to fatty acid synthesis in the seeds of S. tonkinensis were positively correlated with fruit fresh weight and seed crude fat mass fraction.

Key words: brassinolide (BR), Styrax tonkinensis, enzyme activities related to fatty acid synthesis, oil accumulation

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