Sequential functioning of Sym-13 and Sym-31, two genes affecting symbiosome development in root nodules of pea (Pisum sativum L.).
Two Fix- mutants of pea (Pisum sativum L.) which are unable to fix molecular nitrogen, E135f (sym-13) and Sprint-2Fix- (sym-31), were crossed to create the doubly homozygous recessive line, named RBT (sym-13, sym-31). The ultrastructural organization of nodules of the RBT line was compared with that of each of the two parental mutant lines and with the original wild-type genotypes of the cultivars Sparkle and Sprint-2. It was shown that the RBT line is similar to the mutant line Sprint-2Fix- in having abnormal symbiosome composition and bacteroids with relatively undifferentiated morphology. Because the phenotypic manifestation of the sym-31 mutant allele suppresses the phenotypic manifestation of the sym-13 mutant allele, it is concluded that the function of the gene Sym-31 (which is mutated in the Sprint-2Fix- line) is necessary at an earlier stage of symbiosome development than the gene Sym-13 (which is mutant in the E135f line).
Borisov
A Y
AY
All-Russia Research Institute for Agricultural Microbiology, St. Petersburg-Pushkin.
Rozov
S M
SM
Tsyganov
V E
VE
Morzhina
E V
EV
Lebsky
V K
VK
Tikhonovich
I A
IA
D017343:Genes, Plant / Q000235:genetics*; D009154:Mutation; D018532:Pisum sativum / Q000235:genetics / Q000382:microbiology*; D018517:Plant Roots / Q000382:microbiology* / Q000648:ultrastructure; D012231:Rhizobium / Q000502:physiology* / Q000648:ultrastructure; D013559:Symbiosis / Q000235:genetics*