Figure 3: Analyses of mass spectral profiles of proteins of the four well characterized rhizobia reference strains at different growth stages and storage durations. S. meliloti USDA 1002T growth (a) and storage (b), M. tianshanense USDA 3306T growth (c) and storage (d), R. leguminosarum USDA 2370T growth (e) and storage (f), and B. yuanmingense CCBAU 10071T growth (g) and storage (h). 3K-14K stands for all mass fragments by 1000 m/z. 10 h, 18 h, 24 h … 144 h stand for bacterial growth times in hours. RS0D stands for the well-grown fresh bacteria (0 day). 1W, 2W and 3W stand for the storage duration of 1, 2 and 3 weeks, respectively. 4Cstands for the storage temperature 4oC. RT stands for room temperature (21oC). Dots represents protein mass segment, diamonds represents different growth time (10-144 h), squares represent different storage method and duration. Dimension 1 (Dim1) and dimension 2 (Dim2) explained the variation of proteins distribution among the treatments.