Table 1.

Plant material used in the study

Lines	Phenotype	References
SGE	Wild type	Kosterin and Rozov (1993); Tsyganov et al. (1998)
SGEFix−-2 (sym33-3)	‘Locked’ infection threads inside the nodule, occasional bacterial release	Tsyganov et al. (1994, 1998, 2011); Voroshilova et al. (2001, 2009 )
SGEFix−-5 (sym33-2)	‘Locked’ infection threads inside the nodule, no bacterial release	Ovchinnikova et al. (2011); Tsyganov et al. (2013); Tsyganova et al. (2019)
SGEFix−-1 (sym40)	Hypertrophied infection droplets and infection threads, abnormal bacteroids	Tsyganov et al. (1994, 1998); Voroshilova et al. (2009)
SGEFix−-3 (sym26)	Premature degradation of symbiotic structures	Tsyganov et al. (2000); Serova et al. (2018)
Sprint-2	Wild type	Borisov et al., (1994, 1997)
Sprint-2Fix−(sym31)	Undifferentiated bacteroids, several bacteroids are surrounded by a common symbiosome membrane	Borisov et al. (1994, 1997)