Department of Biology, Faculty of Science, Ehime University, Matsuyama, 790-8577, Japan.
J Plant Res. 2013 Nov;126(6):811-21. doi: 10.1007/s10265-013-0568-0. Epub 2013 Jun 4.
We investigated the effect of elicitors on xylem differentiation and lignification using a Zinnia elegans xylogenic culture system. Water-soluble chitosan and a fungal elicitor derived from Botrytis cinerea were used as elicitors. Elicitor addition at the start of culturing inhibited tracheary element (TE) differentiation in a concentration-dependent manner, and 30 μg mL(-1) of chitosan or 16.7 μg mL(-1) of the fungal elicitor strikingly inhibited TE differentiation and lignification. Addition of chitosan (at 50 μg mL(-1)) or the fungal elicitor (at 16.7 μg mL(-1)) during the culturing period also inhibited TE differentiation without inhibiting cell division, except for immature TEs undergoing secondary wall thickening. Elicitor addition after immature TE appearance also caused the accumulation of an extracellular lignin-like substance. It appears that elicitor addition at the start of culturing inhibits the process by which dedifferentiated cells differentiate into xylem cell precursors. Elicitor addition during culturing also appears to inhibit the transition from xylem cell precursors to immature TEs, and induces xylem cell precursors or xylem parenchyma cells to produce an extracellular stress lignin-like substance.
我们使用百日菊木质部培养体系研究了诱导子对木质部分化和木质化的影响。采用水溶性壳聚糖和来自葡萄孢的真菌诱导子作为诱导子。培养开始时添加诱导子可浓度依赖性地抑制导管分化，30μg/mL 壳聚糖或 16.7μg/mL 真菌诱导子可显著抑制导管分化和木质化。在培养期间添加壳聚糖（50μg/mL）或真菌诱导子（16.7μg/mL）也可抑制细胞分裂，除了正在进行次生壁加厚的不成熟导管外，抑制导管分化。在不成熟 TE 出现后添加诱导子也会导致细胞外木质素样物质的积累。似乎在培养开始时添加诱导子会抑制去分化细胞分化为木质部细胞前体的过程。培养期间添加诱导子也可能会抑制木质部细胞前体向不成熟 TE 的转化，并诱导木质部细胞前体或木质部薄壁细胞产生细胞外应激木质素样物质。
