The recent review summarizes the major achievements in discovery of role of phytoglobins in mediation of nitric oxide generated cellular functions in higher plants. Genes encoding non-symbiotic hemoglobins have been cloned from several plant species. The expression pattern of these genes show tissue-specificity that is also under the control of stress factors like hypoxia. The nitric oxide has pivotal role in signalling pathway specifically in hypersensitive reactions and programmed cell death. Production of transgenic tobacco plants overexpressing the alfalfa hemoglobin showed altered necrotic symptoms after treatment with nitric oxide generating compounds or infection by necrotic pathogens. The present review helps to outline the similar relation between hemoglobin and nitric oxide in plants as it was found in animal cells.
Authors:M. Szécsényi, M. Cserháti, Á. Zvara, D. Dudits, and J. Györgyey
In order to study drought stress responses in roots during moderate water shortage, our group has designed an oligonucleotide microarray containing probes for genes annotated as either stress-related or general ones to examine six wheat cultivars. These include two drought-tolerant and four drought-sensitive genotypes, having different root morphology either during optimal or water-deficit stress conditions. After a two-week-long water withdrawal, no significant changes were detected in root weights but various trends were observed in the cultivars. These tendencies showed relevant correlations with expression kinetics of genes encoding proteins related to root growth and development. On the other hand, probes indicating variation in distinct genotypes mainly belonged to the group of stress-related genes which encode proteins that contribute to carbohydrate remodeling, osmoprotectant accumulation, amino acid metabolism, defense against oxidative stress, and regulation of transcription. Hence, these data allow us to focus on major metabolic processes involved in drought adaptation as well as provide a wide selection of candidate genes for further detailed studies.