biostudies-literatureUnknown97(24)Walker SAChanges in intracellular calcium in pea root hairs responding to Rhizobium leguminosarum bv. viciae nodulation (Nod) factors were analyzed by using a microinjected calcium-sensitive fluorescent dye (dextran-linked Oregon Green). Within 1-2 min after Nod-factor addition, there was usually an increase in fluorescence, followed about 10 min later by spikes in fluorescence occurring at a rate of about one spike per minute. These spikes, corresponding to an increase in calcium of approximately 200 nM, were localized around the nuclear region, and they were similar in terms of lag and period to those induced by Nod factors in alfalfa. Calcium responses were analyzed in nonnodulating pea mutants, representing seven loci that affect early stages of the symbiosis. Mutations affecting three loci (syProceedings of the National Academy of Sciences of the United States of America13413-8https://www.ebi.ac.uk/biostudies/studies/S-EPMC27238biostudies-literatureDissection of nodulation signaling using pea mutants defective for calcium spiking induced by nod factors and chitin oligomers.PMC27238Walker SAViprey VDownie JAfalseDissection of nodulation signaling using pea mutants defective for calcium spiking induced by nod factors and chitin oligomers.Changes in intracellular calcium in pea root hairs responding to Rhizobium leguminosarum bv. viciae nodulation (Nod) factors were analyzed by using a microinjected calcium-sensitive fluorescent dye (dextran-linked Oregon Green). Within 1-2 min after Nod-factor addition, there was usually an increase in fluorescence, followed about 10 min later by spikes in fluorescence occurring at a rate of about one spike per minute. These spikes, corresponding to an increase in calcium of approximately 200 nM, were localized around the nuclear region, and they were similar in terms of lag and period to those induced by Nod factors in alfalfa. Calcium responses were analyzed in nonnodulating pea mutants, representing seven loci that affect early stages of the symbiosis. Mutations affecting three loci (sy2000-01-01T00:00:00Z2000 Nov2025-04-19T11:55:03.608Z2019-03-26T22:29:13ZS-EPMC272381107851510.1073/pnas.230440097