Legumes obtain a substantial portion of their nitrogen (N) from symbiotic N2 fixation in root nodules. The glutamine synthetase (GS, EC 6.3.1.2)/glutamate synthase (GOGAT) cycle is responsible for the initial N assimilation. This report describes the analysis of a transgenic alfalfa (Medicago sativa L.) line containing an antisense NADH-GOGAT (EC 1.4.1.14) under the control of the nodule-enhanc...

BACKGROUND The potential biofuel plant Jatropha curcas L. is affected by larvae of Archips micaceanus (Walker), a moth of the family Tortricidae. The hybrid Bacillus thuringiensis (Bt) δ-endotoxin protein Cry1Ab/1Ac confers resistance to lepidopteran insects in transgenic rice. RESULTS Here, we report the production of a marker-free transgenic line of J. curcas (L10) expressing Cry1Ab/1Ac usi...

Water availability is one of the major limiting factors for plant growth. Maize is particularly sensitive to water stress at reproductive stages with a strong impairment of photosynthesis and grain filling. Here, we describe the use of genetic transformation first to assess the role of a candidate gene Asr1-a putative transcription factor-as an explanation for genetically linked drought toleran...

Miscanthus has been proposed as a promising crop for phytoremediation due to its high biomass yield and remarkable adaptability to different environments. However, little is known about the resistance of Miscanthus spp. to cadmium (Cd). To determine any differences in resistance of Miscanthus to Cd, we examined plant growth, net photosynthetic rate (Pn), activities of anti-oxidant and C4 photos...

The aim of this work was to analyse the response of NH4 + assimilation in leaves of tobacco plants (Nicotiana tabacum L. cv. Tennessee 86), to different B applications (B1, 5 M H3BO3; B2, 10 M H3BO3; B3, 20 M H3BO3). The plants were grown under controlled environmental conditions and received a complete nutrient solution. In this experiment, we analysed the foliar concentrations of B and NH4 , ...

Phosphoenolpyruvate carboxylase (PEPC; EC 4.1.1.31) plays a key role during C(4) photosynthesis and is involved in anaplerotic metabolism, pH regulation, and stomatal opening. Heterozygous (Pp) and homozygous (pp) forms of a PEPC-deficient mutant of the C(4) dicot Amaranthus edulis were used to study the effect of reduced PEPC activity on CO(2) assimilation rates, stomatal conductance, and (13)...

A model defining carbon isotope discrimination (delta13C) for crassulacean acid metabolism (CAM) plants was experimentally validated using Kalanchoe daigremontiana. Simultaneous measurements of gas exchange and instantaneous CO2 discrimination (for 13C and 18O) were made from late photoperiod (phase IV of CAM), throughout the dark period (phase I), and into the light (phase II). Measurements of...

A mutant of the NAD-malic enzyme-type C(4) plant, Amaranthus edulis, which lacks phosphoenolpyruvate carboxylase (PEPC) in the mesophyll cells was studied. Analysis of CO(2) response curves of photosynthesis of the mutant, which has normal Kranz anatomy but lacks a functional C(4) cycle, provided a direct means of determining the liquid phase-diffusive resistance of atmospheric CO(2) to sites o...

Crassulacean acid metabolism (CAM) plants exhibit persistent circadian rhythms of CO(2) metabolism. These rhythms are driven by changes in the flux through phosphoenolpyruvate carboxylase, which is regulated by reversible phosphorylation in response to a circadian oscillator. This article reviews progress in our understanding of the circadian expression of phosphoenolpyruvate carboxylase kinase.

Phosphoenolpyruvate carboxylase (PEPC) is a tightly controlled cytosolic enzyme situated at a crucial branch point of central plant metabolism. In developing castor oil seeds (Ricinus communis) a novel, allosterically desensitized 910-kD Class-2 PEPC hetero-octameric complex, arises from a tight interaction between 107-kD plant-type PEPC and 118-kD bacterial-type (BTPC) subunits. The native Ca2...