Cellulose synthesis complexes are homo-oligomeric and hetero-oligomeric in Physcomitrium patens
Cellulose synthesis complexes are homo-oligomeric and hetero-oligomeric in Physcomitrium patens
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DOI：
10.1093/plphys/kiac003
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发表时间：
2022-01-20
期刊：
影响因子：
7.4
通讯作者：
Roberts, Alison W.
中科院分区：
文献类型：
--
作者：
Li, Xingxing;Chaves, Arielle M.;Roberts, Alison W.
藓类植物含有由单一类型纤维素合成酶催化亚基组成的同源寡聚纤维素合成复合物，种子植物和藓类植物的共同祖先含有由单一纤维素合成酶（CESA）基因编码的相同亚基组成的同源寡聚纤维素合成复合物（CSC）。种子植物使用不同的CESA同种型用于初生和次生细胞壁沉积。初级和次级CESA都形成异源寡聚CSC，其仅在所有所需的同种型存在时才在植物中组装和发挥功能。藓类立碗藓（Physcomitrella）patens具有7个CESA基因，其可以被分为两个功能和遗传学上不同的类别。先前，我们表明PpCESA 3和/或PpCESA 8（A类）与PpCESA 6和/或PpCESA 7（B类）一起形成正常次生细胞壁沉积所需的专性异源寡聚复合物。在这里，我们表明，配子体形态需要A类，PpCESA 5的成员，并持续在其他PpCESA亚型的情况下。PpCESA 5也不同于其他A类PpCESA，因为它能够自我相互作用，并且不与其他PpCESA同种型共免疫沉淀。这些结果与仅含有PpCESA 5亚基的同源寡聚CSC合成配子体形态发生所需的纤维素的假设一致。突变表型的分析还揭示，像次生细胞壁沉积一样，正常的原丝体顶端生长需要B类同种型（PpCESA 4或PpCESA 10），沿着A类配偶体（PpCESA 3、PpCESA 5或PpCESA 8）。因此，P. patens含有同源寡聚和异源寡聚CSC。
Mosses contain homo-oligomeric cellulose synthesis complexes composed of a single type of cellulose synthase catalytic subunit.The common ancestor of seed plants and mosses contained homo-oligomeric cellulose synthesis complexes (CSCs) composed of identical subunits encoded by a single CELLULOSE SYNTHASE (CESA) gene. Seed plants use different CESA isoforms for primary and secondary cell wall deposition. Both primary and secondary CESAs form hetero-oligomeric CSCs that assemble and function in planta only when all the required isoforms are present. The moss Physcomitrium (Physcomitrella) patens has seven CESA genes that can be grouped into two functionally and phylogenetically distinct classes. Previously, we showed that PpCESA3 and/or PpCESA8 (class A) together with PpCESA6 and/or PpCESA7 (class B) form obligate hetero-oligomeric complexes required for normal secondary cell wall deposition. Here, we show that gametophore morphogenesis requires a member of class A, PpCESA5, and is sustained in the absence of other PpCESA isoforms. PpCESA5 also differs from the other class A PpCESAs as it is able to self-interact and does not co-immunoprecipitate with other PpCESA isoforms. These results are consistent with the hypothesis that homo-oligomeric CSCs containing only PpCESA5 subunits synthesize cellulose required for gametophore morphogenesis. Analysis of mutant phenotypes also revealed that, like secondary cell wall deposition, normal protonemal tip growth requires class B isoforms (PpCESA4 or PpCESA10), along with a class A partner (PpCESA3, PpCESA5, or PpCESA8). Thus, P. patens contains both homo-oligomeric and hetero-oligomeric CSCs.