Table_5_Comparative Proteomics of Mulberry Leaves at Different Developmental Stages Identify Novel Proteins Function Related to Photosynthesis.XLSX

Mulberry leaves at different positions are different in photosynthetic rate, nutrient substance and feeding impact to silkworms. Here, we investigated the proteomic differences of the first (L1), sixth (L6), and twentieth (L20) mulberry leaves at different stem positions (from top to the base) using a label-free quantitative proteomics approach. L1 contained less developed photosynthetic apparatus but was more active in protein synthesis. L20 has more channel proteins and oxidoreductases relative to L6. Proteins that detected in all measured leaves were classified into three groups according to their expression patterns in L1, L6, and L20. The protein group that displayed the maximum amount in L6 has the highest possibility that function related to photosynthesis. Nine function unknown proteins belong to this group were further analyzed in the light responsive expression, evolutionary tree and sub-cellular localization analysis. Based on the results, five proteins were suggested to be involved in photosynthesis. Taken together, these results reveal the molecular details of different roles of mulberry leaves at different developmental stages and contribute to the identification of five proteins that might function related to photosynthesis.

不同着生位置的桑叶，其光合速率、营养物质组成以及对家蚕的饲喂效果均存在差异。本研究采用无标记定量蛋白质组学（label-free quantitative proteomics）技术，对桑树茎秆不同着生部位（从顶端至基部）的第1片（L1）、第6片（L6）及第20片（L20）桑叶的蛋白质组差异进行了分析。第1片桑叶的光合机构发育尚不完善，但蛋白质合成活性更高。相较于第6片桑叶，第20片桑叶的通道蛋白与氧化还原酶含量更为丰富。在所有被测桑叶中均检测到的蛋白质，根据其在L1、L6和L20中的表达模式被分为3个组别。在L6中表达量最高的蛋白质组，其功能最有可能与光合作用相关。本研究针对该组中9个功能未知的蛋白质，进一步开展了光响应表达、进化树及亚细胞定位分析。基于分析结果，推测其中5个蛋白质可能参与光合作用过程。综上，本研究阐明了不同发育阶段桑树叶片功能分化的分子机制，同时为5个可能参与光合作用的蛋白质的功能鉴定提供了依据。