1-MCP和SO2保鲜剂处理阳光玫瑰葡萄的转录组学分析

Transcriptome analysis of Shine Muscat grape treated with 1-MCP and SO2 preservatives

  • 摘要: 【目的】分析2种保鲜剂处理阳光玫瑰葡萄贮藏阶段基因差异表达情况,为从分子生物学角度研究保鲜剂处理对葡萄果实贮藏品质影响的调控机制提供理论参考。【方法】以阳光玫瑰葡萄为试材,采用1-甲基环丙烯(1-MCP)和二氧化硫(SO2)保鲜剂分别对果实进行冰温贮藏(-1~1℃),并以不使用保鲜剂的果实为对照,对贮藏1、5、9、13和17周的2种保鲜剂处理及对照的果实分别取样开展转录组学分析,通过实时荧光定量PCR结果证实转录组测序结果的可靠性。【结果】从对照和2种保鲜剂处理的转录组测序结果中共获得371.64 Gb的原始数据,各样品Clean data均达6.03 Gb,GC含量为46.28%~47.53%,Q30≥93.50%,与葡萄参考基因组的匹配率为75.75%~90.23%。1-MCP处理与对照的差异表达基因数在贮藏后13周达最高值,而SO2处理与对照及SO2处理与1-MCP处理的差异表达基因数在贮藏后5周达最高值。贮藏1周和13周时,1-MCP处理与对照之间差异表达基因最多,分别为965和2881个;贮藏5周和9周时,SO2处理与对照之间差异表达基因最多,分别为3698和1628个;贮藏17周时,处理和对照两两比较获得的差异表达基因相差不大。贮藏1~5周果实内部发生细胞组分、分子功能和生物过程等方面的变化较贮藏中后期更为剧烈,且在MYB、AP2/ERF-ERF、NAC、GARP-G2-like、HB-HD-ZIP和WRKY转录因子的调控下,单萜合成相关结构基因表达量在贮藏5周后迅速降低。基于实时荧光定量PCR的所有样本中苯丙烷—类黄酮、类胡萝卜素和单萜合成代谢路径相关基因表达水平检测结果与转录组测序分析结果基本一致。【结论】 1-MCP与SO2保鲜剂对阳光玫瑰葡萄贮藏产生不同影响,前者在贮藏过程中抑制果实成熟和衰老作用释放较后者更为平缓,且通过阻断乙烯与受体结合并抑制ETR、EIN3和ERF1/2这3个乙烯信号通路关键基因表达发挥延缓衰老作用。转录因子MYB、AP2/ERFERF、NAC、GARP-G2-like、HB-HD-ZIP和WRKY与单萜合成基因相关性较强,且6类转录因子之间存在较强相关性,其可能通过互作调控果实单萜合成或其他成熟衰老过程。

     

    Abstract: 【Objective】To analyze the gene differential expression of Shine Muscat grape during storage under two preservation treatments,so as to provide theoretical reference for studies on the regulation mechanism of preservative treatments on stored grape fruit quality from the perspective of molecular biology.【Method】Shine Muscat grapes were used as test material, treated with 1-MCP and SO2 preservative agents respectively and then was put in cryogenic storage (-1-1℃). The fruits without any preservative agent were taken as the control. Transcriptome analysis was performed on the fruits treated with each preservative treatment and the control group after 1, 5, 9, 13 and 17 weeks of storage period,respectively. The liability of sequencing was confirmed by qRT-PCR experiment.【Result】 A total of 371.64 Gb of raw data was obtained from the transcriptomic sequencing of groups of two preservative treatments and the control. Clean data of each sample reached 6.03 Gb. GC content was 46.28%-47.53%, and Q30 percentage was more than 93.50%, and the matching rate to grape reference genome was 75.75%-90.23%. The number of DEGs between 1-MCP treatment and control reached the highest value at 13 weeks after storage, while the number of differentially expressed genes(DEGs)between SO2 treatment and control, SO2 treatment and 1-MCP treatment reached the highest value at 5 weeks after storage. At the 1st and 13th weeks of storage. The number of DEGs between 1-MCP treatment and control was 965 and 2881, respectively. The number of DEGs between SO2 treatment and control reached the highest at 3698 and 1628, in the 5th and 9th weeks of storage,respectively. At 17th weeks of storage,no significant difference appeared in the number of differential genes obtained by pairwise comparison between treatment groups and the control. The results also showed that the changes of cellular components, molecular functions and biological processes in fruits during 1-5 weeks of storage were much more dramatic than those in the middle and late stages of storage. Under the regulation of MYB, AP2/ERF-ERF, NAC, GARP-G2-like, HB-HD-ZIP and WRKY transcription factors, the expression of structural genes related to monoterpene biosynthesis decreased rapidly after 5 weeks of storage. The expression of genes related to phenylpropane-flavonoid, carotenoid and monoterpene metabolic pathways in all samples based on real-time quantitative PCR(qRT-PCR)were basically consistent with the transcriptome sequencing analysis results.【Conclusion】1-MCP and SO2 preservative agents have different effects on stored Shine Muscat grape. The former inhibits fruit ripening and senescence more gently than the latter, and delays senescence by blocking ethylene binding to receptors and inhibiting the expression of ETR, EIN3 and ERF1/2, three key genes in ethylene signaling pathway. Transcription factors MYB, AP2/ERF-ERF, NAC, GARP-G2- like, HB-HD-ZIP and WRKY are strongly correlated with monoterpenoid synthesis genes. Correlations among the six transcription factors which may regulate monoterpenoid synthesis or other ripening and senescence processes through interaction are obvious.

     

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