Rapid sequence evolution is associated with genetic incompatibilities in the plastid Clp complex
Rapid sequence evolution is associated with genetic incompatibilities in the plastid Clp complex
复制标题
DOI：
10.1007/s11103-022-01241-4
复制
发表时间：
2022-01-17
影响因子：
5.1
通讯作者：
Sloan, Daniel B.
中科院分区：
文献类型：
--
作者：
Abdel-Ghany, Salah E.;LaManna, Lisa M.;Sloan, Daniel B.
关键信息用来自不同供体物种的同源物替换烟草质体基因组中的天然clpP 1基因表明，遗传不相容性的程度取决于序列进化的速率。质体酪蛋白分解蛋白酶（Clp）复合物在维持蛋白质稳态中起重要作用，包括质体编码和核编码的亚基。尽管Clp复合物在大多数物种中被保留在具有高度保守蛋白质序列的绿色植物中，但在许多被子植物中已经鉴定出氨基酸置换速率极快的实例。这些加速的原因一直是广泛猜测的主题，但仍然不清楚。为了区分流行的假设和开始了解Clp亚基的快速序列差异的功能后果，我们使用质体转化，以取代天然clpP1基因在烟草（烟草）与来自另一个被子植物属（Silene），表现出广泛的Clp蛋白序列进化的速率。我们发现，植物介导的选择可以驱动一个缓慢进化的供体物种的转基因clpP1替代（S。latifolia）的clpP1拷贝变为同质，但来自具有加速进化速率的蝇子草属物种的clpP1拷贝保持异质，这意味着它们不能在功能上替代必需的烟草clpP1基因。这些结果表明，观察到的情况下，快速Clp序列进化的上位不相容性，必须改善质体和核亚基之间的共同进化反应的来源。
Key message Replacing the native clpP1 gene in the Nicotiana plastid genome with homologs from different donor species showed that the extent of genetic incompatibilities depended on the rate of sequence evolution. The plastid caseinolytic protease (Clp) complex plays essential roles in maintaining protein homeostasis and comprises both plastid-encoded and nuclear-encoded subunits. Despite the Clp complex being retained across green plants with highly conserved protein sequences in most species, examples of extremely accelerated amino acid substitution rates have been identified in numerous angiosperms. The causes of these accelerations have been the subject of extensive speculation but still remain unclear. To distinguish among prevailing hypotheses and begin to understand the functional consequences of rapid sequence divergence in Clp subunits, we used plastome transformation to replace the native clpP1 gene in tobacco (Nicotiana tabacum) with counterparts from another angiosperm genus (Silene) that exhibits a wide range in rates of Clp protein sequence evolution. We found that antibiotic-mediated selection could drive a transgenic clpP1 replacement from a slowly evolving donor species (S. latifolia) to homoplasmy but that clpP1 copies from Silene species with accelerated evolutionary rates remained heteroplasmic, meaning that they could not functionally replace the essential tobacco clpP1 gene. These results suggest that observed cases of rapid Clp sequence evolution are a source of epistatic incompatibilities that must be ameliorated by coevolutionary responses between plastid and nuclear subunits.