Extensin, an underestimated key component of cell wall defence?
Extensin, an underestimated key component of cell wall defence?
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DOI：
10.1093/aob/mcab001
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发表时间：
2021-05-07
期刊：
影响因子：
4.2
通讯作者：
Driouich, Azeddine
中科院分区：
文献类型：
--
作者：
Castilleux, Romain;Plancot, Barbara;Driouich, Azeddine
背景：伸展蛋白是植物细胞壁富含羟基脯氨酸的糖蛋白，已知在高等植物中参与细胞壁加固和防御病原体攻击。延伸蛋白形成分子内和分子间交联的能力与它们在细胞壁加固中的作用直接相关。这种交联的形成需要适当的糖基化和糖蛋白的结构构象。范围：虽然细胞壁成分在植物防御中的作用近年来引起了越来越多的兴趣，但相对较少的焦点是致力于扩展蛋白。然而，最近关于伸展蛋白的结构和作用及其糖基化在植物-微生物相互作用中的新见解，引起了细胞壁界专家的有趣争论。我们之前已经发现，在拟南芥野生型根和受鞭毛蛋白22激发的扩展蛋白突变体中，扩展蛋白表位具有明显的分布。该研究最近在Tan和Mort的评论中进行了辩论（Tan L, Mort a . 2020）。植物防御前线的延伸。对“扩展蛋白阿拉伯糖基化参与对激发子的根反应并限制卵菌定植”的评论。《植物学年鉴》（Annals of Botany） 125: vii-viii)，并对我们的结果进行了讨论。作为回应，我们在此澄清Tan和Mort提出的观点，并更新抗延伸蛋白单克隆抗体可能识别的表位结构。我们还提供了额外的数据，表明在PEROXIDASES 33和34缺陷突变体和野生型之间，LM1扩展蛋白表位在根中的分布存在差异，类似于先前对扩展蛋白阿拉伯糖基化缺陷的rra2突变体的观察结果。我们提出这两种过氧化物酶作为潜在的候选者特异性催化细胞壁内延伸蛋白的交联。结论：伸展蛋白在细胞壁内起着重要的保护根的作用。延伸蛋白的交联，需要正确的糖基化和特定的过氧化物酶，最有可能导致细胞壁结构的调节，从而增强根细胞对入侵病原体的保护。研究延伸蛋白糖基化及其交联之间的关系是进一步了解细胞壁如何影响根免疫的一个很有前途的途径。
Background: Extensins are plant cell wall hydroxyproline-rich glycoproteins known to be involved in cell wall reinforcement in higher plants, and in defence against pathogen attacks. The ability of extensins to form intra- and intermolecular cross-links is directly related to their role in cell wall reinforcement. Formation of such cross-links requires appropriate glycosylation and structural conformation of the glycoprotein.Scope: Although the role of cell wall components in plant defence has drawn increasing interest over recent years, relatively little focus has been dedicated to extensins. Nevertheless, new insights were recently provided regarding the structure and the role of extensins and their glycosylation in plant-microbe interactions, stimulating an interesting debate from fellow cell wall community experts. We have previously revealed a distinct distribution of extensin epitopes in Arabidopsis thaliana wild-type roots and in mutants impaired in extensin arabinosylation, in response to elicitation with flagellin 22. That study was recently debated in a Commentary by Tan and Mort (Tan L, Mort A. 2020. Extensins at the front line of plant defence. A commentary on: 'Extensin arabinosylation is involved in root response to elicitors and limits oomycete colonization'. Annals of Botany 125: vii-viii) and several points regarding our results were discussed. As a response, we herein clarify the points raised by Tan and Mort, and update the possible epitope structure recognized by the anti-extensin monoclonal antibodies. We also provide additional data showing differential distribution of LM1 extensin epitopes in roots between a mutant defective in PEROXIDASES 33 and 34 and the wild type, similarly to previous observations from the rra2 mutant defective in extensin arabinosylation. We propose these two peroxidases as potential candidates to specifically catalyse the cross-linking of extensins within the cell wall.Conclusions: Extensins play a major role within the cell wall to ensure root protection. The cross-linking of extensins, which requires correct glycosylation and specific peroxidases, is most likely to result in modulation of cell wall architecture that allows enhanced protection of root cells against invading pathogens. Study of the relationship between extensin glycosylation and their cross-linking is a very promising approach to further understand how the cell wall influences root immunity.