Convergent evolution of hetero‐oligomeric cellulose synthesis complexes in mosses and seed plants
Convergent evolution of hetero‐oligomeric cellulose synthesis complexes in mosses and seed plants
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苔藓和种子植物异源低聚纤维素合成复合物的趋同进化
DOI：
10.1111/tpj.14366
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Roberts, Alison W.
中科院分区：
文献类型：
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作者：
Li, Xingxing;Speicher, Tori L.;Dees, Dianka C. T.;Mansoori, Nasim;McManus, John B.;Tien, Ming;Trindade, Luisa M.;Wallace, Ian S.;Roberts, Alison W.
在种子植物中，纤维素通过专性异源寡聚的玫瑰花形纤维素合成复合物（CSC）合成，其包含三种不可互换的纤维素合酶（CESA）同种型。立碗藓具有莲座状CSC和7个CESA基因，但其与种子植物的共同祖先具有莲座状CSC和1个CESA基因。因此，如果P.patensCSC是异源寡聚的，那么这种类型的CSC在苔藓和种子植物中会聚进化。先前的基因敲除和启动子交换实验表明，来自A类（PpCESA 3和PpCESA 8）和B类（PpCESA 6和PpCESA 7）的PpCESA在叶中脉中的次生细胞壁纤维素沉积中具有非冗余功能，而每类的两个成员是冗余的。基于这些观察结果，我们提出了次级A类和B类PpCESA缔合形成异源寡聚CSC的假设。在这里，我们表明，二级类APpCESAs的转录减少时，二级类BPpCESAs被敲除，反之亦然，如预期的基因编码的同种型，占据不同的位置在同一CSC。A类和B类同种型在发育中的配子体和免疫共沉淀物中共同积累，表明它们相互作用形成植物复合物。最后，次级PpCESA彼此相互作用，而当在两种不同的异源系统中表达时，四种中的三种不能自我相互作用。这些结果与专性异源寡聚CSC在苔藓和种子植物中独立进化的假设一致，我们提出了建设性中性进化假说作为异源寡聚CSC趋同进化的合理解释。
In seed plants, cellulose is synthesized by rosette‐shaped cellulose synthesis complexes (CSCs) that are obligate hetero‐oligomeric, comprising three non‐interchangeable cellulose synthase (CESA) isoforms. The mossPhyscomitrella patenshas rosette CSCs and seven CESAs, but its common ancestor with seed plants had rosette CSCs and a single CESA gene. Therefore, ifP. patensCSCs are hetero‐oligomeric, then CSCs of this type evolved convergently in mosses and seed plants. Previous gene knockout and promoter swap experiments showed that PpCESAs from class A (PpCESA3 and PpCESA8) and class B (PpCESA6 and PpCESA7) have non‐redundant functions in secondary cell wall cellulose deposition in leaf midribs, whereas the two members of each class are redundant. Based on these observations, we proposed the hypothesis that the secondary class A and class B PpCESAs associate to form hetero‐oligomeric CSCs. Here we show that transcription of secondary class APpCESAs is reduced when secondary class BPpCESAs are knocked out and vice versa, as expected for genes encoding isoforms that occupy distinct positions within the same CSC. The class A and class B isoforms co‐accumulate in developing gametophores and co‐immunoprecipitate, suggesting that they interact to form a complexin planta. Finally, secondary PpCESAs interact with each other, whereas three of four fail to self‐interact when expressed in two different heterologous systems. These results are consistent with the hypothesis that obligate hetero‐oligomeric CSCs evolved independently in mosses and seed plants and we propose the constructive neutral evolution hypothesis as a plausible explanation for convergent evolution of hetero‐oligomeric CSCs.