Hybrid Label-Free Molecular Microscopies for Simultaneous Visualization of Changes in Cell Wall Polysaccharides of Peach at Single- and Multiple-Cell Levels during Postharvest Storage
Hybrid Label-Free Molecular Microscopies for Simultaneous Visualization of Changes in Cell Wall Polysaccharides of Peach at Single- and Multiple-Cell Levels during Postharvest Storage
复制标题
混合无标记分子显微镜可同时可视化采后储存期间桃细胞壁多糖在单细胞和多细胞水平上的变化
DOI：
10.3390/cells9030761
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发表时间：
2020-03-01
期刊：
影响因子：
6
通讯作者：
Chen, Kunsong
中科院分区：
文献类型：
--
作者：
Huang, Weinan;Nie, Yating;Chen, Kunsong
果实采后软化主要与细胞壁内多糖的组成和空间变化有关，影响果实的质构和品质。目前对果实软化机理的研究缺乏对细胞水平上的整体软化的理解。以桃为试材，研究了采后果肉细胞壁多糖在单细胞和多细胞水平上的空间分布变化。不化桃（Prunus persica L.）Batsch cv.”商品成熟度的“中华寿桃”）在0 °C和20 °C下储存。在每个储存时间进行硬度测量和化学分析。此外，利用共焦拉曼显微光谱（CRM）、傅里叶变换红外显微光谱（FTIRM）和受激拉曼散射显微镜（SRS）3种分子成像技术，对桃果实采后贮藏过程中细胞壁多糖的空间分布变化进行了无标记的可视化研究。CRM和FTIRM的结合提供了互补的光谱信息，以可视化的纤维素，半纤维素，果胶在细胞壁中的软化过程中在单细胞水平的空间变化，并发现细胞壁多糖倾向于集中在薄壁细胞的细胞角在后期。此外，SRS是一种超快拉曼成像技术（比CRM快大约三或四个数量级），用于高通量细胞壁表型测量。对SRS数据进行灰度统计分析，发现果实软化过程中薄壁细胞的降解程度不同。总的来说，细胞壁多糖在软化过程中逐渐减少，后期大多数薄壁细胞趋于集中在细胞角处，但也有一些细胞与整个软化趋势不一致。结果表明，在桃果实软化过程中，不同薄壁细胞间细胞壁多糖的含量和空间变化存在差异，CRM、FTIRM和SRS的混合使用是一种很有前途的同时可视化桃果实细胞壁多糖变化的方法。
Softening of fruit during the postharvest storage, which is mainly associated with both compositional and spatial changes of polysaccharides within cell wall, affects the texture and quality of fruit. Current research on the fruit softening mechanism lacks an understanding of the overall softening at the cell level. The objective of this work was to investigate the change in the spatial distribution of cell wall polysaccharides in peach flesh cells at both single- and multiple-cell levels in a label-free way during the postharvest storage. Nonmelting peaches (Prunus persica L. Batsch cv.”Zhonghuashoutao”) at commercial maturity were stored at 0 °C and 20 °C. Firmness measurement and chemical analysis were performed at each storage time. In addition, three molecular imaging techniques, namely confocal Raman microspectroscopy (CRM), Fourier transform infrared microspectroscopy (FTIRM), and stimulated Raman scattering microscopy (SRS) were used to visualize changes in the spatial distribution of cell wall polysaccharides of peach fruit in a label-free way during the postharvest storage. The combination of CRM and FTIRM provided complementary spectral information to visualize the spatial changes of cellulose, hemicellulose, and pectin in the cell wall of peach flesh during softening at the single-cell level, and found that the cell wall polysaccharides tended to be concentrated in the cell corner of parenchymal cells at the late stage. Furthermore, SRS, which is an ultrafast Raman imaging technique (approximately three or four orders of magnitude faster than CRM), was used for high-throughput cell wall phenotypes measurement. Different degradation degrees of parenchymal cells during fruit softening were found based on the gray-scale statistical analysis of SRS data. In general, cell wall polysaccharides decreased during softening and tended to be concentrated in the cell corner for most parenchymal cells at the late stage, but there were also some cells not in line with the whole softening trends. The results show that there were differences in the content and spatial changes of cell wall polysaccharides among parenchymal cells of peach fruit during the softening process, and the hybrid use of CRM, FTIRM, and SRS is a promising method for simultaneous visualization of changes in cell wall polysaccharides of peach.