CAJ | 학술논문

现代陆生植物的祖先大约在5亿到4．7亿年前登陆，这是植物进化过程中的重要事件。光照不仅是植物的主要能量来源，还是主要的环境信息来源之一。一般认为，光合作用效率越高，植物的适应能力越强。植物登陆过程前后，环境从光照、光强到二氧化碳／氧气浓度比等都发生了变化，比如适应陆地生活的海草重新返回水生环境，猜测在这个过程中植物光合作用的相关的关键功能基因可能发生了进化。为了证明该假说，以链形植物门绿藻和低等陆地植物为主要研究对象，通过从GenBank收集相关基因序列以及从几株相近绿藻中提取测定DNA序列，利用PAML“分枝－位点”模型对光合作用光反应和暗反应中的psbA、rbcL、rca 3个基因进行了适应性进化分析。结果显示植物登陆过程前后，在这3个光合作用相关基因中均未检测到统计上显著的正选择位点，反而在绿色植物早期分化（绿藻门和链形植物门）过程中却发现有明显的正选择痕迹。这些惊人的结果提示植物登陆前后从水体到陆地的环境变化对光合作用的影响可能并不大，其它诸如角质膜、气孔器等相关的基因可能发挥了更大的作用。
현대륙생식물적조선대약재5억도4．7억년전등륙，저시식물진화과정중적중요사건。광조불부시식물적주요능량래원，환시주요적배경신식래원지일。일반인위，광합작용효솔월고，식물적괄응능력월강。식물등륙과정전후，배경종광조、광강도이양화탄／양기농도비등도발생료변화，비여괄응륙지생활적해초중신반회수생배경，시측재저개과정중식물광합작용적상관적관건공능기인가능발생료진화。위료증명해가설，이련형식물문록조화저등륙지식물위주요연구대상，통과종GenBank수집상관기인서렬이급종궤주상근록조중제취측정DNA서렬，이용PAML“분지－위점”모형대광합작용광반응화암반응중적psbA、rbcL、rca 3개기인진행료괄응성진화분석。결과현시식물등륙과정전후，재저3개광합작용상관기인중균미검측도통계상현저적정선택위점，반이재록색식물조기분화（록조문화련형식물문）과정중각발현유명현적정선택흔적。저사량인적결과제시식물등륙전후종수체도륙지적배경변화대광합작용적영향가능병불대，기타제여각질막、기공기등상관적기인가능발휘료경대적작용。
The ancestors of modern land plants colonized the terrestrial habitat about 500 to 470 million years ago , this is an important event in the history of life on earth .Illumination is not only the primary energy for plants , but also the main environmental information sources.It is widely accepted that the higher efficiency of photosynthesis , the stronger ability of plants to adapt the environment .When plants began to colonize the terrestrial habitat , their environment significantly changed , such as illumination , light intensity and the concentration ratio of carbon dioxide and oxygen just like seagrasses went back to the sea .Therefore , we hypothesize that there are evi-dences for adaptive evolution of photosynthesis-related genes in plants .To test this hypothesis , detection of adaptive evolution was per-formed on psbA, rbcL, rca genes using PAML′s"site-branch"model.As a result, no significant evidence of positive selection of these three genes was detected in the plant colonization , whereas there was remarkable divergence between Chlorophyta and Streptophyta. This amazing result implies that environmental changes during plants colonizing the terrestrial habitat may have few influences on photo -synthesis-related genes .Genes related to other functions like cuticle and stomatal apparatus played important roles in this course .