DkXTH8, a novel xyloglucan endotransglucosylase/hydrolase in persimmon, alters cell wall structure and promotes leaf senescence and fruit postharvest softening.
DkXTH8, a novel xyloglucan endotransglucosylase/hydrolase in persimmon, alters cell wall structure and promotes leaf senescence and fruit postharvest softening.
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DKXTH8是一种新型的木糖酸葡聚糖内旋糖基糖基化酶/水解酶，在柿子中改变细胞壁结构，并促进叶片衰老和果实后的柔软后果实。
DOI：
10.1038/srep39155
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发表时间：
2016-12-14
影响因子：
4.6
通讯作者：
Rao J
中科院分区：
文献类型：
--
作者：
Han Y;Ban Q;Li H;Hou Y;Jin M;Han S;Rao J
果实软化主要与细胞壁结构修饰相关，并且木葡聚糖内切转葡糖基酶/水解酶（XTH）家族的成员是参与切割和重新连接细胞壁中的木葡聚糖的关键酶。本研究从柿果实中克隆了一个新的XTH基因DkXTH 8。转录谱分析表明，DkXTH 8达到峰值，在戏剧性的果实软化，和DkXTH 8的表达刺激丙烯和脱落酸，但抑制赤霉酸和1-MCP。洋葱表皮细胞中的瞬时表达测定表明DkXTH 8通过其信号肽直接定位于细胞壁。当在体外表达时，重组DkXTH 8蛋白表现出严格的木葡聚糖内糖基转移酶活性，而没有观察到木葡聚糖内水解酶活性。此外，过表达DkXTH 8导致拟南芥叶片衰老增加，电解质渗漏增加，番茄果实成熟和软化速度加快。最重要的是，过表达DkXTH 8的转基因植物由于细胞壁重组而显示出更多的不规则和扭曲的细胞，导致更宽的间隙空间和更少的致密细胞。我们认为DkXTH 8的表达导致细胞容易被破坏，增加膜透性和细胞过氧化，并加速叶片衰老和果实软化转基因植物。
Fruit softening is mainly associated with cell wall structural modifications, and members of the xyloglucan endotransglucosylase/hydrolase (XTH) family are key enzymes involved in cleaving and re-joining xyloglucan in the cell wall. In this work, we isolated a new XTH gene, DkXTH8, from persimmon fruit. Transcriptional profiling revealed that DkXTH8 peaked during dramatic fruit softening, and expression of DkXTH8 was stimulated by propylene and abscisic acid but suppressed by gibberellic acid and 1-MCP. Transient expression assays in onion epidermal cells indicated direct localization of DkXTH8 to the cell wall via its signal peptide. When expressed in vitro, the recombinant DkXTH8 protein exhibited strict xyloglucan endotransglycosylase activity, whereas no xyloglucan endohydrolase activity was observed. Furthermore, overexpression of DkXTH8 resulted in increased leaf senescence coupled with higher electrolyte leakage in Arabidopsis and faster fruit ripening and softening rates in tomato. Most importantly, transgenic plants overexpressing DkXTH8 displayed more irregular and twisted cells due to cell wall restructuring, resulting in wider interstitial spaces with less compact cells. We suggest that DkXTH8 expression causes cells to be easily destroyed, increases membrane permeability and cell peroxidation, and accelerates leaf senescence and fruit softening in transgenic plants.
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影响因子：
6.9
作者：
Han Y;Wang W;Sun J;Ding M;Zhao R;Deng S;Wang F;Hu Y;Wang Y;Lu Y;Du L;Hu Z;Diekmann H;Shen X;Polle A;Chen S
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影响因子：
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作者：
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通讯作者：
Moya-Leon, Maria Alejandra
影响因子：
7.2
作者：
Clough, SJ;Bent, AF
通讯作者：
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