Fluctuations of nitrogenase and cytosol glutamine synthetase activity in pea (Pisum sativum L.) nodules in the course of vegetation

Škrdleta, V.; Gaudinová, Alena; Našinec, V.; Němcová, Marie; Našincová, V.

doi:10.1007/bf02880483

Cited by 5 publications

(1 citation statement)

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“…The mRNA for cytosolic GS, GS polypeptides and GS activity in nitrogen-fixing effective nodules of pea increased during plant development while those in roots remained low (Tingey et al 1987;Suganuma et al 1999). The highest GS activity was found in young nodules, 15 days after inoculation in pea plants (Sˇkrdleta et al 1980).…”

Section: Introductionmentioning

confidence: 91%

Overexpression of a soybean cytosolic glutamine synthetase gene linked to organ-specific promoters in pea plants grown in different concentrations of nitrate

Fei

Chaillou

Hirel

et al. 2003

Planta

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A glutamine synthetase gene (GS15) coding for soybean cytosolic glutamine synthetase (GS1) fused to a constitutive promoter (CaMV 35S), a putative nodule-specific promoter (LBC 3 ) and a putative rootspecific promoter (rolD) was transformed into Pisum sativum L. cv. Greenfeast. Four lines with single copies of GS15 (one 35S-GS15 line, one LBC 3 -GS15 line, and two rolD-GS15 lines) were tested for the expression of GS15, levels of GS1, GS activity, N accumulation, N 2 fixation, and plant growth at different levels of nitrate. Enhanced levels of GS1 were detected in leaves of three transformed lines (the 35S-GS15 and rolD-GS15 transformants), in nodules of three lines (the LBC 3 -GS15 and rolD-GS15 transformants), and in roots of all four transformants. Despite increased levels of GS1 in leaves and nodules, there were no differences in GS activity in these tissues or in whole-plant N content, N 2 fixation, or biomass accumulation among all the transgenic lines and the wild-type control. However, the rolD-GS15 transformants, which displayed the highest levels of GS1 in the roots of all the transformants, had significantly higher GS activity in roots than the wild type. In one of the rolD-GS15 transformed lines (Line 8), increased root GS activity resulted in a lower N content and biomass accumulation, supporting the findings of earlier studies with Lotus japonicus (Limami et al. 1999 ). However, N content and biomass accumulation was not negatively affected in the other rolD-GS15 transformant (Line 9) and, in fact, these parameters were positively affected in the 0.1 mM NO À 3 treatment. These findings indicate that overexpression of GS15 in various tissues of pea does not consistently result in increases in GS activity. The current study also indicates that the increase in root GS activity is not always consistent with decreases in plant N and biomass accumulation and that further investigation of the relationship between root GS activity and growth responses is warranted.Keywords Glutamine synthetase AE Nitrate AE Pisum AE Transgenic peaAbbreviations CaMV: cauliflower mosaic virus AE GS: glutamine synthetase AE GS1: cytosolic GS AE GS2: plastidic GS AE GS15: a soybean cytosolic glutamine synthetase gene AE NDFA: the amount of nitrogen derived from the atmosphere AE WT: wild type, non-transformed control Planta (2003) 216: 467-474

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Section: Introductionmentioning

confidence: 91%