PDF(Pubmed)
Abstract：
Prasiola crispa, an aerial green alga, exhibits remarkable adaptability to the extreme conditions of Antarctica by forming layered colonies capable of utilizing far-red light for photosynthesis. Despite a recent report on the structure of P. crispa\'s unique light-harvesting chlorophyll (Chl)-binding protein complex (Pc-frLHC), which facilitates far-red light absorption and uphill excitation energy transfer to photosystem II, the specific genes encoding the subunits of Pc-frLHC have not yet been identified. Here, we report a draft genome sequence of P. crispa strain 4113, originally isolated from soil samples on Ongul Island, Antarctica. We obtained a 92 Mbp sequence distributed in 1,045 scaffolds comprising 10,244 genes, reflecting 87.1% of the core eukaryotic gene set. Notably, 26 genes associated with the light-harvesting Chl a/b binding complex (LHC) were identified, including four Pc-frLHC genes, with similarity to a noncanonical Lhca gene with four transmembrane helices, such as Ot_Lhca6 in Ostreococcus tauri and Cr_LHCA2 in Chlamydomonas reinhardtii. A comparative analysis revealed that Pc-frLHC shares homology with certain Lhca genes found in Coccomyxa and Trebouxia species. This similarity indicates that Pc-frLHC has evolved from an ancestral Lhca gene with four transmembrane helices and branched out within the Trebouxiaceae family. Furthermore, RNA-seq analysis conducted during the initiation of Pc-frLHC gene induction under red light illumination indicated that Pc-frLHC genes were induced independently from other genes associated with photosystems or LHCs. Instead, the genes of transcription factors, helicases, chaperones, heat shock proteins, and components of blue light receptors were identified to coexpress with Pc-frLHC. Those kinds of information could provide insights into the expression mechanisms of Pc-frLHC and its evolutional development.
摘要：
Prasiolacrispa,空中绿藻，通过形成能够利用远红光进行光合作用的分层菌落，对南极洲的极端条件表现出显着的适应性。尽管最近有关于P.crispa独特的光捕获叶绿素（Chl）结合蛋白复合物（Pc-frLHC）结构的报道，这有利于远红光的吸收和上坡激发能量转移到光系统II，编码Pc-frLHC亚基的特定基因尚未鉴定。这里,我们报告了P.crispa菌株4113的基因组序列草案，最初分离自Ongul岛的土壤样品，南极洲。我们获得了分布在1,045个支架中的92Mbp序列，包含10,244个基因，反映了87.1%的核心真核基因集。值得注意的是,鉴定了与捕光Chla/b结合复合物（LHC）相关的26个基因，包括四个Pc-frLHC基因,与具有四个跨膜螺旋的非经典Lhca基因相似，如牛链球菌中的Ot_Lhca6和衣藻中的Cr_LHCA2。比较分析表明，Pc-frLHC与在Coccomyxa和Trebouxia物种中发现的某些Lhca基因具有同源性。这种相似性表明Pc-frLHC是从具有四个跨膜螺旋的祖先Lhca基因进化而来的，并在Trebouxiaceae家族中分支出来。此外，在红光照射下启动Pc-frLHC基因诱导过程中进行的RNA-seq分析表明，Pc-frLHC基因的诱导独立于与光系统或LHC相关的其他基因。相反，转录因子的基因，解旋酶,监护人,热休克蛋白，蓝光受体的成分与Pc-frLHC共表达。这些信息可以为Pc-frLHC的表达机制及其进化发展提供见解。
