Płachno Bartosz J, Kapusta Małgorzata, Feldo Marcin, Świątek Piotr
Department of Plant Cytology and Embryology, Institute of Botany, Faculty of Biology, Jagiellonian University in Kraków, 9 Gronostajowa St., 30-387 Cracow, Poland.
Bioimaging Laboratory, Faculty of Biology, University of Gdańsk, 59 Wita Stwosza St., 80-308 Gdansk, Poland.
Int J Mol Sci. 2024 Dec 6;25(23):13124. doi: 10.3390/ijms252313124.
The (bladderworts) species are carnivorous plants that prey mainly on invertebrates using traps (bladders) of leaf origin. On the outer surfaces of the trap, there are dome-shaped glands (capitate trichomes). Each such trichome consists of a basal cell, a pedestal cell, and a terminal cell. During the maturation of these external glands, there are changes in the cell wall of the terminal cell of the gland (deposited layers of secondary wall material). Thus, due to changes in the cell wall, these glands are excellent models for studying the specialization of cell walls. The main aim of this study was to check whether different cell wall layers in terminal gland cells have a different composition in the case of homogalacturonans (low-methylesterified HGs, fully de-esterified HGs, and galactan) and hemicelluloses (galactoxyloglucan, xyloglucan, and xylan). The antibodies were used against cell wall components (anti-pectins JIM5, JIM7, LM19, CCRC-M38, and LM5 and anti-hemicelluloses LM25, LM15, CCRC-M1, and CCRC-M138). The localization of the examined compounds was determined using immunohistochemistry techniques, Carbotrace 680, and Calcofluor White. Our study showed the presence of various components in the cell walls of external gland cells: methylesterified and demethylesterified homogalacturonans, galactan, xylan, galactoxyloglucan, and xyloglucan. In the terminal cell, the primary cell wall contains different pectins in contrast to the secondary wall material, which is rich in cellulose and hemicelluloses. We also found that the basal cell differs from the other gland cells by the presence of galactan in the cell wall, which resembles the epidermal cells and parenchyma of traps. A particularly noteworthy part of the cell wall functions as a Casparian strip in the pedestal cell. Here, we found no labeling with Carbotrace 680, possibly due to cell wall modification or cell wall chemical composition variation. We have shown that the apoplastic space formed by the cell walls of the terminal cell is mainly composed of cellulose and hemicelluloses (galactoxyloglucan and xyloglucan). This composition of the cell walls allows the easy uptake of components from the external environment. Our research supports the external glands' function as hydropotens.
狸藻属植物是肉食性植物，主要利用叶源捕虫囊捕食无脊椎动物。在捕虫囊的外表面，有圆顶形腺体（头状毛状体）。每个这样的毛状体由一个基部细胞、一个柄细胞和一个末端细胞组成。在这些外部腺体成熟过程中，腺末端细胞的细胞壁会发生变化（次生壁物质的沉积层）。因此，由于细胞壁的变化，这些腺体是研究细胞壁特化的优秀模型。本研究的主要目的是检查在同型半乳糖醛酸聚糖（低甲基酯化的同型半乳糖醛酸聚糖、完全去酯化的同型半乳糖醛酸聚糖和半乳聚糖）和半纤维素（半乳糖木葡聚糖、木葡聚糖和木聚糖）的情况下，末端腺细胞中不同的细胞壁层是否具有不同的组成。使用了针对细胞壁成分的抗体（抗果胶JIM5、JIM7、LM19、CCRC-M38和LM5以及抗半纤维素LM25、LM15、CCRC-M1和CCRC-M138）。使用免疫组织化学技术、Carbotrace 680和荧光增白剂测定所检测化合物的定位。我们的研究表明，外部腺细胞的细胞壁中存在各种成分：甲基酯化和去甲基酯化的同型半乳糖醛酸聚糖、半乳聚糖、木聚糖、半乳糖木葡聚糖和木葡聚糖。在末端细胞中，初生细胞壁含有不同的果胶，与富含纤维素和半纤维素的次生壁物质形成对比。我们还发现，基部细胞与其他腺细胞的不同之处在于其细胞壁中存在半乳聚糖，这与捕虫囊的表皮细胞和薄壁组织相似。细胞壁中一个特别值得注意的部分在柄细胞中起到了凯氏带的作用。在这里，我们没有发现Carbotrace 680的标记，可能是由于细胞壁修饰或细胞壁化学成分变化。我们已经表明，由末端细胞的细胞壁形成的质外体空间主要由纤维素和半纤维素（半乳糖木葡聚糖和木葡聚糖）组成。细胞壁的这种组成使得能够轻松摄取来自外部环境的成分。我们的研究支持了外部腺体作为水压感受器的功能。
