Functional understanding of secondary cell wall cellulose synthases in Populus trichocarpa via the Cas9/gRNA-induced gene knockouts.-猫眼课题宝

通过 Cas9/gRNA 诱导的基因敲除对毛果杨次生细胞壁纤维素合酶的功能了解。

DOI：

10.1111/nph.17338

发表时间：

2021-08

期刊：

The New phytologist

影响因子：

通讯作者：

中科院分区：

其他

文献类型：

作者：

Xu W;Cheng H;Zhu S;Cheng J;Ji H;Zhang B;Cao S;Wang C;Tong G;Zhen C;Mu L;Zhou Y;Cheng Y

来源链接：

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8362133/

植物纤维素由大型质膜定位纤维素合酶 (CesA) 复合物合成。然而，树木中次生细胞壁 (SCW) CesAs 的整体功能测定仍然缺乏，尤其是基于基因敲除的测定。在这里，Cas9/gRNA 诱导的 PtrCesA4、7A、7B、8A 和 8B 基因敲除是在毛果杨中产生的。基于解剖学、免疫组织化学和木材成分证据，我们在基因水平上对五种SCW PtrCesAs有了全面的了解。 PtrCesA4、7A/B 或 8A/B 的完全缺失导致类似的形态异常，表明相似且非冗余的遗传功能。这些突变木材中缺乏凝胶状 (G) 层、单层壁纤维以及纤维素减少 90%，这表明三类 SCW PtrCesAs 对于多层 SCW 结构和木材 G 纤维至关重要。此外，突变的初生和次生韧皮部纤维失去了n(G + L)层和G层，并保留了较厚的S层（L，木质化；S，次生）。结合多糖免疫定位数据，这些发现表明 SCW PtrCesAs 合成的纤维素在木材和韧皮部纤维壁结构中的作用存在差异。总体而言，对 SCW PtrCesAs 的功能理解提供了进一步了解缺乏纤维素生物合成对树中生长、SCW、木材 G 纤维和韧皮部纤维壁结构的影响。

Plant cellulose is synthesized by a large plasma membrane‐localized cellulose synthase (CesA) complex. However, an overall functional determination of secondary cell wall (SCW) CesAs is still lacking in trees, especially one based on gene knockouts. Here, the Cas9/gRNA‐induced knockouts of PtrCesA4, 7A, 7B, 8A and 8B genes were produced in Populus trichocarpa. Based on anatomical, immunohistochemical and wood composition evidence, we gained a comprehensive understanding of five SCW PtrCesAs at the genetic level. Complete loss of PtrCesA4, 7A/B or 8A/B led to similar morphological abnormalities, indicating similar and nonredundant genetic functions. The absence of the gelatinous (G) layer, one‐layer‐walled fibres and a 90% decrease in cellulose in these mutant woods revealed that the three classes of SCW PtrCesAs are essential for multilayered SCW structure and wood G‐fibre. In addition, the mutant primary and secondary phloem fibres lost the n(G + L)‐ and G‐layers and retained the thicker S‐layers (L, lignified; S, secondary). Together with polysaccharide immunolocalization data, these findings suggest differences in the role of SCW PtrCesAs‐synthesized cellulose in wood and phloem fibre wall structures. Overall, this functional understanding of the SCW PtrCesAs provides further insights into the impact of lacking cellulose biosynthesis on growth, SCW, wood G‐fibre and phloem fibre wall structures in the tree.