Extended Data Fig. 3: Root-associated microbial community analyses of N2-fixing and non-N2-fixing P. oceanica plants.
From: Terrestrial-type nitrogen-fixing symbiosis between seagrass and a marine bacterium
(a) N2 fixation rates of roots of individual plants with each symbol representing individual root pieces. (b) Relative abundance of 16S rRNA gene-based OTUs (‘others’ are classes with less than 1.5%) in individually analysed plants. Asterisks indicate plants with sequencing results below the threshold for the calculation of α-diversity. (c) Ratio of Celerinatantimonas–related reads to organellar reads. Lines, boxes, and error bars represent mean, 25th and 75th percentiles and standard deviation, respectively. (d) Number of shared OTUs as a function of their presence in an increasing number of plants (as % of plants in both categories) with Venn diagram showing the number of unique and shared OTUs. (e) α-diversity indices where boxes indicate second and third quartiles, whiskers indicate first and fourth quartiles, lines indicate median values and black dots are the individual plants. Differences in α-diversity indices were not statistically significant (Kruskal-Wallis pairwise tests). (f) First two axes of a principal component analysis (PCA) using Aitchison distance based on OTU counts, highlighting statistically significant microbial community compositions in N2-fixing (square symbols) and non-N2-fixing (diamond symbols) plants (pairwise Permanova, peudo-F = 7.9, q-value = 0.001). Colors indicate seasons (spring (blue), summer (yellow) and autumn (orange); the brown diamond represents a spring and a summer sample on top of each other). Arrow indicates the OTU contributing most to the clustering of samples, i.e. Ca. C. neptuna. (g) Ranking of differentially abundant OTUs (x-axis). Negative and positive log ratios indicate higher abundance in non-N2-fixing and N2-fixing plants, respectively. Highlighted in magenta is the Ca. C. neptuna-OTU, the highest ranked OTU positively associated with N2 fixation. The number of plants (n) included in the analyses is indicated in parentheses in panels c and e.
