Table 4. Quantification of Mollicutes-related endobacteria and Candidatus Glomeribacter gigasporarum detected with real-time qPCR.

Batch	Biological replicates	Mre average	Mre standard deviation	CaGg average	CaGg standard deviation	Ratio
A
1	7	927	729	179	140	5.17
5	6	3963	1608	648	400	6.12
10	5	10752	3266	1897	1121	5.67
B
1	7	463	364	179	140	2.59
5	6	1982	804	648	400	3.06
10	5	5376	1633	1897	1121	2.83

The quantification was performed for batches of 1, 5 and 10 spores considering at least five biological replicates. The ratio is obtained by dividing the number of Mollicutes-related endobacteria for that of Candidatus Glomeribacter gigasporarum. We observe high variability in the quantification of 16S rRNA gene sequences of both types of endobacteria when single spores are analyzed, with this variation being reduced when batches of multiple spores are considered. This pattern is consistent with previous observations that CaGg abundance in individual spores can vary greatly (Jargeat et al., 2004). (A) The qPCR analysis revealed that Mre are 5.17–6.12 times more abundant than CaGg in the Gigaspora margarita CM23 spores, assuming that a single copy of the 16S rRNA gene is present in the Mre genome. (B) The value should be reduced to 2.59–3.06 times if two copies of the 16S rRNA gene are present in Mre genomes.