串珠藻目植物psaA基因的适应性进化及共进化分析  

Adaptive Evolutionary and Co-evolutionary Analysis on psaA Gene of Batrachospermales

作　　者：巩超彦 南芳茹 冯佳[1] 吕俊平[1] 刘琪[1] 刘旭东 谢树莲[1] GONG Chaoyan;NAN Fangru;FENG Jia;LU Junping;LIU Qi;LIU Xudong;XIE Shulian(School of Life Science,Shanxi University,Taiyuan 030006 China)

机构地区：[1]山西大学生命科学学院

出　　处：《山西大学学报（自然科学版）》2019年第3期662-672,共11页Journal of Shanxi University(Natural Science Edition)

基　　金：国家自然科学基金(31670208)

摘　　要：串珠藻目是淡水红藻中最重要的类群。psaA基因是植物叶绿体中进行光调节的重要基因,编码光系统Ⅰ反应中心跨膜复合物的中心蛋白A,又称P700脱辅基蛋白A,承担重要的生物学功能,构成植物光系统Ⅰ的中心架构。为了探究串珠藻目植物适应特殊生存环境的分子水平机制,选取串珠藻目及一些相近类群淡水红藻的psaA基因42条,并采用PAML4.8软件中的位点模型、分支模型和分支-位点模型,对选取类群的psaA基因进行了适应性进化分析。结果表明:(1)所有内类群聚集为9个分支,其中,分支A为假枝藻属,分支B为Nocturama属,分支C为西斯藻属,分支D为连珠藻,分支E为胶串珠藻,分支F为熊野藻属,分支G为串珠藻属,分支H为暗紫红毛菜,分支I为红索藻属;(2)没有在位点模型和分支-位点模型中检测到有统计学意义的正选择位点,提示该基因处于强烈的负选择作用之下并具有保守性;(3)基于详细的解析数据和氨基酸对的相关系数统计出共进化组(对)5组(20对),序列中所有共进化氨基酸对的平均距离27.808 6?,标准差12.325 2,基于氨基酸疏水相关性值统计出的共进化组(对)5组(12对),基于氨基酸分子量相关值统计出的共进化组(对)5组(15对),其中共有11对共进化氨基酸同疏水性、分子量都显著相关。本研究结果显示psaA基因在串珠藻目植物中是非常保守的,比较适用于属及以上分类单元群体的系统发育关系研究,同时,基于ω比值检验基因适应性进化具有准确性和有效性。Batrachospermales is the most important group of freshwater red algae.The psaA.is an important gene in plant chloroplasts for light regulation.It encodes the central protein A of the transmembrane complex of the reaction center of the photosystemⅠ,also known as P700 apoprotein A,and bears important biological functions,constituting the central architecture of plant photosystemⅠ.In order to explore the molecular mechanism of them to adapt to the special living environment,42 psaA genes of Batrachospermales and other relative taxa were selected to analyze the adaptive evolution.Using software PAML4.8,the site model,branch model,and branch-site model were tested.The results show that(1)all the internal groups cluster into nine branches in the phylogenetic tree constructed by the maximum likelihood method,i.e.,the cluster A is the genus Nothocladus,B is the genus Nocturama C is the genus Sheathia,D is Sirodotia suecica,E is Batrachospermum gelatinosum,F is the genus Kumanoa,G is the genus Batrachospermum,H is Bangia atropurpurea and Ⅰ is the genus Thorea;(2)In site model and branch-site model,no statistically significant positive selection sites were detected in the selected 9 branches,suggesting psaA gene is conservative and under strong negative selection in various groups.(3)Five co-evolution groups(20 pairs of co-evolution sites)were identified based on the detailed analysis data and the correlation coefficient of the amino acid.The average distance of all co-evolution amino acid pairs in the sequence was 27.808 6 A,and the standard deviation was 12.325 2.Based on the amino acid hydrophobicity correlation value,5 co-evolution groups(12 pairs of co-evolution site)were identified,and 5 co-evolution groups(15 pairs of co-evolution site)were identified based on the amino acid molecular weight correlation values.11 pairs of co-evolution sites of center proteinA of PS Ⅰ were significantly related to the hydrophobicity and molecular weight of amino acids.The results showed that the psaA.gene is very conservative

关 键 词：串珠藻目 psaA基因 适应性进化 共进化 

分 类 号：Q941[生物学—植物学]