Emission of nitrous oxide (N₂O) from transgenic tobacco expressing antisense NiR mRNA

Abstract

SummaryThe emission of N 2 and N 2 O from intact transgenic tobacco (clone 271) expressing antisense nitrite reductase (NiR) mRNA, and wild-type plants grown aseptically, on NO 3 ± , NO 2 ± or NH 4 + -containing medium was investigated. 15 N contents of gas sampled from gassealed pots, in which the plants were grown on 15 Ncontaining medium, were analyzed by gas chromatography and mass spectrometry (GC±MS

Conversion of the Nitrate Nitrogen and Nitrogen Dioxide to Nitrous Oxides in Plants

“…The transgenic tobacco used here (line 271) bears chimeric nitrite reductase (NiR) cDNA in an antisense orientation [39] and thus practically lacks NiR activity (less than 5% of the wild type). These tobacco plants were aseptically cultivated on B medium [36] for seven weeks as described previously in [21]. They were then fumigated with 1 or 4 ppm of 15 NO 2 (51.6 atom% 15 N) for five days (fumigation period), after which they were transferred onto a B medium [36] in gas-sealed pots without the addition of NO 2 and the cultivation was continued for three days (emission period).…”

“…Finally, they were transferred onto an MS medium in gassealed pots, in which the nitrogen source was replaced by 50 mM non-labelled KNO 3 and the culture was continued for one week (emission period). At the end of the cultivation, gas samples were collected and 15 N 2 O was analysed by gas chromatography-mass spectrometry equipped with a precondensing apparatus (FINNIGAN MAT Instrument Inc., Germany) as previously described [21].…”

“…Detached wheat leaves that take up nitrite ions were reported to emit N 2 [16], but the plant material used in these experiments was not grown aseptically, and the possibility that microorganisms participated in the denitrification could therefore not be excluded. Recently it has been reported that a transgenic tobacco, in which nitrite reductase activity is suppressed to less than 5% of the wild type is emitting nitrous oxide (N 2 O) when fed with 15 N-labelled nitrate or nitrite [21]. More recently, SMART and Bloom [22] have reported that wheat leaves emit significant amounts of nitrous oxide, and that the nitrous oxide production in leaves occurred during the photoassimilation of nitrite ions in the chloroplast.…”

Nitrous oxide emissions from two alpine meadows in the Qinghai–Tibetan Plateau

“…Meanwhile, evidence shows that soil moisture (Bouwman 1996;Del Prado et al 2006;Du 2006;Li et al 2004), temperature (Bouwman 1996;Du 2006) and grazing (Velthof and Oenema 1997) as well as N fertilization (Del Prado et al 2006;Stehfest and Bouwman 2006;Velthof and Oenema 1997) have a great impact on N 2 O emissions from grasslands. Recent research has identified that some plants have the capacity to emit N 2 O to the atmosphere (Goshima et al 1999;Zhang and Jiang 2006;Zou et al 2005).…”

Nitrite accumulation and nitric oxide emission in relation to cellular signaling in nitrite reductase antisense tobacco

“…This plant accumulated nitrite at least 5-fold over the wild-type (WT) level (Vaucheret et al 1992) and produced N 2 O with increasing nitrite levels in plant tissues (Goshima et al 1999). We used this transgenic line to investigate the consequences of nitrite accumulation on the production of NO AE and derivatives, with particular emphasis on the nitration state of tyrosine residues of proteins.…”