Extracellular Proteins in Pea Root Tip and Border Cell Exudates1[OA]
Extracellular Proteins in Pea Root Tip and Border Cell Exudates1[OA]
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DOI：
10.1104/pp.106.091637
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发表时间：
2006-12
期刊：
影响因子：
7.4
通讯作者：
Fushi Wen;H. Vanetten;G. Tsaprailis;M. Hawes
中科院分区：
文献类型：
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作者：
Fushi Wen;H. Vanetten;G. Tsaprailis;M. Hawes
新生的植物组织天生对感染很敏感。然而，当豌豆（Pisum sativum）的根接种了豌豆病原体红扁豆（Nectria haematococca）时，大多数新生成的根尖仍然未被感染，即使大多数根在根尖后面的伸长区域发生病变。阻力机制尚不清楚，但在空间上与帽周边缘细胞的存在有关。先前，发现在边界细胞分离进行时释放了一系列bbb100细胞外蛋白。在这里，我们报道了豌豆根冠的蛋白质分泌与边缘细胞分离有关。当该根帽分泌组蛋白水解降解后，感染根尖的比例从4%±3%增加到100%。在对照实验中，分生孢子和根的蛋白酶处理对真菌和植株的生长发育没有影响。通过多维蛋白鉴定技术，证实了一个由bbbb100细胞外蛋白组成的复合体构成了根冠分泌组。除了已知存在于植物外质体中的防御相关酶和信号转导酶外，还有核糖体蛋白、14-3-3蛋白和其他通常与细胞内定位相关，但最近被证明是微生物生物膜的细胞外成分。我们得出的结论是，长期以来，人们都知道根冠可以释放高分子量的多糖黏液和数千个活细胞到早期根际，同时还分泌一种复杂的蛋白质混合物，似乎可以保护根尖免受感染。
Newly generated plant tissue is inherently sensitive to infection. Yet, when pea (Pisum sativum) roots are inoculated with the pea pathogen, Nectria haematococca, most newly generated root tips remain uninfected even though most roots develop lesions just behind the tip in the region of elongation. The resistance mechanism is unknown but is correlated spatially with the presence of border cells on the cap periphery. Previously, an array of >100 extracellular proteins was found to be released while border cell separation proceeds. Here we report that protein secretion from pea root caps is induced in correlation with border cell separation. When this root cap secretome was proteolytically degraded during inoculation of pea roots with N. haematococca, the percentage of infected root tips increased from 4% ± 3% to 100%. In control experiments, protease treatment of conidia or roots had no effect on growth and development of the fungus or the plant. A complex of >100 extracellular proteins was confirmed, by multidimensional protein identification technology, to comprise the root cap secretome. In addition to defense-related and signaling enzymes known to be present in the plant apoplast were ribosomal proteins, 14-3-3 proteins, and others typically associated with intracellular localization but recently shown to be extracellular components of microbial biofilms. We conclude that the root cap, long known to release a high molecular weight polysaccharide mucilage and thousands of living cells into the incipient rhizosphere, also secretes a complex mixture of proteins that appear to function in protection of the root tip from infection.