Estimation of Stomatal Aperture in Using Silicone Rubber Imprints.

Estimation of stomatal aperture using low viscosity silicone-base impression material has the advantage of working with the whole leaf. The developmental stage and the environment strongly affect the stomatal aperture. Therefore, it is mandatory to have accurate estimations of the stomatal aperture of intact leaves under different situations.

Overexpression of AtERF019 delays plant growth and senescence, and improves drought tolerance in Arabidopsis.

The transcription factor superfamily, APETALA2/ethylene response factor, is involved in plant growth and development, as well as in environmental stress responses. Here, an uncharacterized gene of this family, AtERF019, was studied in Arabidopsis thaliana under abiotic stress situations. Arabidopsis plants overexpressing AtERF019 showed a delay in flowering time of 7 days and a delay in senescence of 2 weeks when comparison with wild type plants.

Overexpression of AtWRKY30 enhances abiotic stress tolerance during early growth stages in Arabidopsis thaliana.

AtWRKY30 belongs to a higher plant transcription factor superfamily, which responds to pathogen attack. In previous studies, the AtWRKY30 gene was found to be highly and rapidly induced in Arabidopsis thaliana leaves after oxidative stress treatment. In this study, electrophoretic mobility shift assays showed that AtWRKY30 binds with high specificity and affinity to the WRKY consensus sequence (W-box), and also to its own promoter.

Contribution of a harpin protein from Xanthomonas axonopodis pv. citri to pathogen virulence.

Xanthomonas axonopodis pv. citri (Xac), the bacterium that causes citrus canker, contains a gene in the hrp [for hypersensitive response (HR) and pathogenicity] cluster that encodes a harpin protein called Hpa1. Hpa1 produced HR in the nonhost plants tobacco, pepper and Arabidopsis, whereas, in the host plant citrus, it elicited a weak defence response with no visible phenotype.

Investigating the role of plant heat shock proteins during oxidative stress.

Oxidative stress, arising from an imbalance in the generation and removal of reactive oxygen species (ROS), is a challenge faced by all aerobic organisms. In plants, different pathways sense ROS from extracellular sources or organelles such as mitochondria, chloroplast or peroxisome. In our recent paper on Plant Molecular Biology1 we have studied the Arabidopsis thaliana early response to the generation of superoxide anion in chloroplasts during active photosynthesis.

Generation of hydrogen peroxide in chloroplasts of Arabidopsis overexpressing glycolate oxidase as an inducible system to study oxidative stress.

Arabidopsis (Arabidopsis thaliana) overexpressing glycolate oxidase (GO) in chloroplasts accumulates both hydrogen peroxide (H(2)O(2)) and glyoxylate. GO-overexpressing lines (GO plants) grown at 75 micromol quanta m(-2) s(-1) show retarded development, yellowish rosettes, and impaired photosynthetic performance, while at 30 micromol quanta m(-2) s(-1), this phenotype virtually disappears. The GO plants develop oxidative stress lesions under photorespiratory conditions but grow like wild-type plants under nonphotorespiratory conditions.

Generation of superoxide anion in chloroplasts of Arabidopsis thaliana during active photosynthesis: a focus on rapidly induced genes.

The antioxidant defense system involves complex functional coordination of multiple components in different organelles within the plant cell. Here, we have studied the Arabidopsis thaliana early response to the generation of superoxide anion in chloroplasts during active photosynthesis. We exposed plants to methyl viologen (MV), a superoxide anion propagator in the light, and performed biochemical and expression profiling experiments using Affymetrix ATH1 GeneChip microarrays under conditions in which photosynthesis and antioxidant enzymes were active.

Plant nutritional status modulates glutamine synthetase levels in ripe tomatoes (Solanum lycopersicum cv. Micro-Tom).

Tomato (Solanum lycopersicum) fruit ripening implies that chloroplastic proteins are degraded and new proteins are synthesized. Supplementary nutrition is frequently required when tomato plants begin to fruit and continues until the end of the plant's life cycle. Ammonium assimilation is crucial in these fruit maturation and ripening processes.