Arabinosyl Deacetylase Modulates the Arabinoxylan Acetylation Profile and Secondary Wall Formation
Arabinosyl Deacetylase Modulates the Arabinoxylan Acetylation Profile and Secondary Wall Formation
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DOI：
10.1105/tpc.18.00894
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发表时间：
2019-03
期刊：
影响因子：
11.6
通讯作者：
Lanjun Zhang;Chengxu Gao;F. Mentink-Vigier;Lu Tang;Dongmei Zhang;Shaogan Wang;Shaoxue Cao;Zuopeng Xu;Xiangling Liu;Tuo Wang;Yihua Zhou;Baocai Zhang
中科院分区：
文献类型：
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作者：
Lanjun Zhang;Chengxu Gao;F. Mentink-Vigier;Lu Tang;Dongmei Zhang;Shaogan Wang;Shaoxue Cao;Zuopeng Xu;Xiangling Liu;Tuo Wang;Yihua Zhou;Baocai Zhang
水稻DARX 1是一种GDSL酯酶，其从阿拉伯木聚糖的过量乙酰化阿拉伯糖基取代基上修剪乙酰基，并调节木聚糖构象和次生壁结构。乙酰化是细胞壁聚合物的一种普遍修饰，是一个严格控制的调控过程，协调植物生长和环境适应。然而，由于有限的表征所涉及的酶，目前还不清楚植物如何建立和动态调节乙酰化模式，以响应生长的要求。在这项研究中，我们确定了一个水稻（水稻）GDSL酯酶，脱乙酰化的侧链的主要水稻半纤维素，阿拉伯木聚糖。乙酰酯酶参与阿拉伯木聚糖修饰筛选使用酶结合质谱分析。一种候选物，木聚糖1的阿拉伯糖基侧链脱乙酰酶（DARX 1），对阿拉伯糖残基具有特异性。通过Tos 17插入和CRISPR/Cas9方法破坏DARX 1导致乙酸酯在木聚糖阿拉伯糖基侧链上积累。重组DARX 1在体外消除了darx 1突变体的阿拉伯聚糖衍生的寡糖上的过量乙酰基。此外，DARX 1定位于高尔基体。二维13 C-13 C相关光谱和原子力显微镜进一步揭示，在darx 1中观察到的异常乙酰化模式中断了阿拉伯木聚糖构象和纤维素微纤维取向，导致次生壁图案化受损和机械强度降低。这项研究提供了深入了解阿拉伯木聚糖侧链的乙酰化模式的控制机制，并提出了一个策略，以培育强大的精英作物。
Rice DARX1 is a GDSL esterase that trims acetyl groups from excess acetylated arabinosyl substituents of arabinoxylan and modulates xylan conformation and secondary wall architecture. Acetylation, a prevalent modification of cell-wall polymers, is a tightly controlled regulatory process that orchestrates plant growth and environmental adaptation. However, due to limited characterization of the enzymes involved, it is unclear how plants establish and dynamically regulate the acetylation pattern in response to growth requirements. In this study, we identified a rice (Oryza sativa) GDSL esterase that deacetylates the side chain of the major rice hemicellulose, arabinoxylan. Acetyl esterases involved in arabinoxylan modification were screened using enzymatic assays combined with mass spectrometry analysis. One candidate, DEACETYLASE ON ARABINOSYL SIDECHAIN OF XYLAN1 (DARX1), is specific for arabinosyl residues. Disruption of DARX1 via Tos17 insertion and CRISPR/Cas9 approaches resulted in the accumulation of acetates on the xylan arabinosyl side chains. Recombinant DARX1 abolished the excess acetyl groups on arabinoxylan-derived oligosaccharides of the darx1 mutants in vitro. Moreover, DARX1 is localized to the Golgi apparatus. Two-dimensional 13C-13C correlation spectroscopy and atomic force microscopy further revealed that the abnormal acetylation pattern observed in darx1 interrupts arabinoxylan conformation and cellulose microfibril orientation, resulting in compromised secondary wall patterning and reduced mechanical strength. This study provides insight into the mechanism controlling the acetylation pattern on arabinoxylan side chains and suggests a strategy to breed robust elite crops.