Department of Botany, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, 541 24, Greece.
Section of Botany, Department of Biology, National and Kapodistrian University of Athens, Athens, 157 84, Greece.
Plant Physiol Biochem. 2022 Nov 15;191:78-88. doi: 10.1016/j.plaphy.2022.09.020. Epub 2022 Sep 28.
Cyanobacterial toxins (known as cyanotoxins) disrupt the plant cytoskeleton (i.e. microtubules and F-actin), which is implicated in the regulation of cell wall architecture. Therefore, cyanotoxins are also expected to affect cell wall structure and composition. However, the effects of cyanobacterial toxicity on plant cell wall have not been yet thoroughly studied. Accordingly, the alterations of cell wall matrix after treatments with pure microcystin-LR (MC-LR), or cell extracts of one MC-producing and one non-MC-producing Microcystis strain were studied in differentiated Oryza sativa (rice) root cells. Semi-thin transverse sections of variously treated LR-White-embedded roots underwent immunostaining for various cell wall epitopes, including homogalacturonans (HGs), arabinogalactan-proteins (AGPs), and hemicelluloses. Homogalacturonan and arabinan distribution patterns were altered in the affected roots, while a pectin methylesterase (PME) activity assay revealed that PMEs were also affected. Elevated intracellular Ca levels, along with increased callose and mixed linkage glucans (MLGs) deposition, were also observed after treatment. Xyloglucans appeared unaffected and lignification was not observed. The exact mechanism of cyanobacterial toxicity against the cell wall is to be further investigated.
蓝藻毒素（也称为蓝藻毒素）会破坏植物细胞骨架（即微管和 F-肌动蛋白），而细胞骨架与细胞壁结构的调节有关。因此，蓝藻毒素也可能影响细胞壁的结构和组成。然而，蓝藻毒性对植物细胞壁的影响尚未得到充分研究。因此，本研究分别用纯微囊藻毒素-LR（MC-LR）和一株产 MC 蓝藻与一株非产 MC 蓝藻的细胞提取物处理分化的水稻（Oryza sativa）根细胞，研究了细胞壁基质的变化。用各种方法处理的 LR-White 包埋根的半薄横切片进行了各种细胞壁抗原的免疫染色，包括同质半乳糖醛酸聚糖（HG）、阿拉伯半乳聚糖蛋白（AGP）和半纤维素。受影响的根中同质半乳糖醛酸聚糖和阿拉伯聚糖的分布模式发生了改变，而过甲基酯酶（PME）活性测定显示 PME 也受到了影响。处理后还观察到细胞内 Ca 水平升高，以及几丁质和混合连接葡聚糖（MLG）的沉积增加。木葡聚糖似乎不受影响，也没有观察到木质化。蓝藻毒性对细胞壁的确切机制还需要进一步研究。
