Bilkey Natasha, Li Huiyong, Borodinov Nikolay, Ievlev Anton V, Ovchinnikova Olga S, Dixit Ram, Foston Marcus
Department of Biology, Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, Missouri 63130, USA.
Department of Energy, Environmental and Chemical Engineering, Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, Missouri 63130, USA.
Quant Plant Biol. 2022 Dec 23;3:e31. doi: 10.1017/qpb.2022.20. eCollection 2022.
Spatial heterogeneity in composition and organisation of the primary cell wall affects the mechanics of cellular morphogenesis. However, directly correlating cell wall composition, organisation and mechanics has been challenging. To overcome this barrier, we applied atomic force microscopy coupled with infrared (AFM-IR) spectroscopy to generate spatially correlated maps of chemical and mechanical properties for paraformaldehyde-fixed, intact epidermal cell walls. AFM-IR spectra were deconvoluted by non-negative matrix factorisation (NMF) into a linear combination of IR spectral factors representing sets of chemical groups comprising different cell wall components. This approach enables quantification of chemical composition from IR spectral signatures and visualisation of chemical heterogeneity at nanometer resolution. Cross-correlation analysis of the spatial distribution of NMFs and mechanical properties suggests that the carbohydrate composition of cell wall junctions correlates with increased local stiffness. Together, our work establishes new methodology to use AFM-IR for the mechanochemical analysis of intact plant primary cell walls.
初生细胞壁组成和结构的空间异质性影响细胞形态发生的力学过程。然而，直接关联细胞壁组成、结构和力学性质一直具有挑战性。为克服这一障碍，我们应用原子力显微镜结合红外（AFM-IR）光谱技术，生成了经多聚甲醛固定的完整表皮细胞壁化学和力学性质的空间相关图谱。通过非负矩阵分解（NMF）对AFM-IR光谱进行反褶积，得到代表不同细胞壁组分化学基团集合的红外光谱因子的线性组合。这种方法能够从红外光谱特征定量化学组成，并以纳米分辨率可视化化学异质性。对NMF空间分布与力学性质的互相关分析表明，细胞壁连接点的碳水化合物组成与局部硬度增加相关。我们的工作共同建立了利用AFM-IR对完整植物初生细胞壁进行机械化学分析的新方法。
