Reduction of pectin may decrease the embryogenicity of grapevine (Vitis vinifera) pro-embryonic masses after 10 years of in vitro culture
Reduction of pectin may decrease the embryogenicity of grapevine (Vitis vinifera) pro-embryonic masses after 10 years of in vitro culture
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DOI：
10.1016/j.scienta.2022.111690
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发表时间：
2023-02
影响因子：
4.3
通讯作者：
Xuena Yu;Meng-Jiao Lu;Min Zhou;Hong-yan Wang;Jiayue Feng;Ying-Qiang Wen
中科院分区：
文献类型：
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作者：
Xuena Yu;Meng-Jiao Lu;Min Zhou;Hong-yan Wang;Jiayue Feng;Ying-Qiang Wen
植物体细胞胚是木本植物繁殖、种质保存和遗传转化的最佳材料。然而，大多数木本植物胚性培养物在长期继代培养后胚性再生潜力降低或丧失，并且在长期离体培养过程中与胚性培养物相关的形态和生理变化在很大程度上是未知的。在这项研究中，我们比较葡萄藤原胚群众（PEMs）10年后，不断组织培养与新诱导的PEMs。结果表明，经过长期继代培养后，PEMs的体细胞胚诱导率显著下降，异常胚率高达92.2%。此外，新诱导的葡萄藤PEMs由均匀的胚性细胞团组成。而长期传代培养的PEM，其典型的细胞簇结构几乎消失，相邻细胞间的间距增大。值得注意的是，果胶含量显着下降，在长期继代培养的PEM细胞壁中，沿着果胶甲酯酶活性的降低和多聚半乳糖醛酸酶活性的增加。同时，细胞壁中的果胶主要是甲基化果胶，无论是在新诱导的葡萄藤PEM中还是在10年生的PEM中，脱甲基果胶都很少或几乎检测不到。尽管如此，这两种类型的果胶在长期传代培养的PEM中均以较低水平存在。因此，我们推测，甲基化和去甲基化果胶在长期继代培养的葡萄藤PEMs的减少可能已经破坏了细胞壁力学，这影响了PEMs发育成胚的能力。这项研究为葡萄藤PEM的长期继代培养提供了新的见解。
Plant somatic embryos are the best materials for woody plant reproduction, germplasm preservation and genetic transformation. However, the embryonic regeneration potential of most woody plant embryogenic cultures is reduced or lost after long-term subculture, and the morphological and physiological changes associated with embryogenic cultures during long-termin vitroculture are largely unknown. In this study, we compared grapevine pro-embryonic masses (PEMs) after 10 years of constant tissue culture with newly induced PEMs. The results showed that the somatic embryo induction rate of PEMs decreased significantly after long-term subculture, and up to 92.2% of abnormal embryos appeared. Moreover, the newly induced grapevine PEMs were composed of uniform embryogenic cell clusters. However, the classic cell cluster structure almost disappeared and the space between adjacent cells increased in the long-term subcultured PEMs. Notably, pectin content decreased significantly in the cell walls of the long-term subcultured PEMs, along with a decrease in pectin methylesterase activity and an increase in polygalacturonase activity. Meanwhile, pectin in the cell wall was predominantly methylated pectin, with less or almost undetectable de-methylated pectin not only in the newly induced grapevine PEMs but also in the 10-year-old PEMs. Nonetheless, both types of pectin were present at lower levels in long-term subcultured PEMs. Therefore, we speculate that the decrease in methylated and de-methylated pectin in the long-term subcultured grapevine PEMs may have destroyed the cell wall mechanics, which affected the ability of PEMs to develop into embryos. This study provides new insight into the long-term subculture of grapevine PEMs.