Structural studies of alfalfa roots infected with nodulation mutants of Rhizobium meliloti.
Alfalfa roots infected with four nodulation defective (Nod-) mutants of Rhizobium meliloti which were generated by transposon Tn5 mutagenesis were examined by light and electron microscopy. In one class of Nod- mutants, which we can nonreactive, the bacteria did not induce root hair curling or penetrate host cells. In a second class of Nod- mutants, which we call reactive, the bacteria induced some root hair curling and entered root epidermal cells, although no infection threads were formed. In addition, reactive Nod- mutants induced extensive root hair proliferation and hypertrophied roots. This study presents the details of the phenotype of the association between each mutant strain and alfalfa roots.
D000455:Medicago sativa / Q000382:microbiology / Q000648:ultrastructure; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D009154:Mutation; D010944:Plants / Q000382:microbiology* / Q000648:ultrastructure; D012231:Rhizobium / Q000235:genetics* / Q000648:ultrastructure