Chivasa Stephen, Simon William J, Yu Xiao-Lan, Yalpani Nasser, Slabas Antoni R
School of Biological and Biomedical Sciences, University of Durham, South Road, Durham DH1 3LE, UK.
Proteomics. 2005 Dec;5(18):4894-904. doi: 10.1002/pmic.200500047.
The extracellular matrix is a vital compartment in plants with a prominent role in defence against pathogen attack. Using a maize cell suspension culture system and pathogen elicitors, responses to pathogen attack that are localised to the extracellular matrix were examined by a proteomic approach. Elicitor treatment of cell cultures induced a rapid change in the phosphorylation status of extracellular peroxidases, the apparent disappearance of a putative extracellular beta-N-acetylglucosamonidase, and accumulation of a secreted putative xylanase inhibitor protein. Onset of the defence response was attended by an accumulation of glyceraldehyde-3-phosphate dehydrogenase and a fragment of a putative heat shock protein. Several distinct spots of both proteins, which preferentially accumulated in cell wall protein fractions, were identified. These three novel observations, viz. (i) secretion of a new class of putative enzyme inhibitor, (ii) the apparent recruitment of classical cytosolic proteins into the cell wall and (ii) the change in phosphorylation status of extracellular matrix proteins, suggest that the extracellular matrix plays a complex role in defence. We discuss the role of the extracellular matrix in signal modulation during pathogen-induced defence responses.
细胞外基质是植物中的一个重要区室，在抵御病原体攻击方面发挥着重要作用。利用玉米细胞悬浮培养系统和病原体激发子，通过蛋白质组学方法研究了定位于细胞外基质的对病原体攻击的反应。用激发子处理细胞培养物会导致细胞外过氧化物酶的磷酸化状态迅速改变、一种假定的细胞外β-N-乙酰氨基葡萄糖苷酶明显消失以及一种分泌的假定木聚糖酶抑制蛋白的积累。防御反应开始时伴随着甘油醛-3-磷酸脱氢酶和一种假定热休克蛋白片段的积累。鉴定出了这两种蛋白质的几个不同斑点，它们优先积累在细胞壁蛋白组分中。这三个新发现，即（i）一类新的假定酶抑制剂的分泌，（ii）经典胞质蛋白明显被招募到细胞壁中，以及（iii）细胞外基质蛋白磷酸化状态的变化，表明细胞外基质在防御中发挥着复杂的作用。我们讨论了细胞外基质在病原体诱导的防御反应信号调节中的作用。
