General aspects regarding the presence of nonsymbiotic haemoglobin in plants are presented with the emphasis on those related to its function. As it becomes apparent that the nonsymbiotic haemoglobins are widespread across the plant kingdom and that they represent a more primitive and evolutionary older form of the plant globin genes, the question of their function becomes more attractive. While the physiological functions of the symbiotic haemoglobins in plants are well understood, almost nothing is known about their nonsymbiotic predecessors. Therefore, the known and hypothetical functions of haemoglobins in various systems are described along with information concerning properties and the regulation of expression of the nonsymbiotic haemoglobins. Interestingly, a number of nonsymbiotic haemoglobins have been shown to be hypoxia-inducible. The spatial and temporal pattern of this induction in barley may suggest that it is an integral part of the plants response to limiting oxygen stress.
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Molecules
March 2024
Department of Chemistry, Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Arany Janos Str. No. 11, RO-400028 Cluj-Napoca, Romania.
Nonsymbiotic phytoglobins (nsHbs) are a diverse superfamily of hemoproteins grouped into three different classes (1, 2, and 3) based on their sequences. Class 1 Hb are expressed under hypoxia, osmotic stress, and/or nitric oxide exposure, while class 2 Hb are induced by cold stress and cytokinins. Both are mainly six-coordinated.
View Article and Find Full Text PDFBiology (Basel)
February 2024
Crop Research Institute, Shandong Academy of Agricultural Sciences, Jinan 250100, China.
Ammonium (NH) toxicity is ubiquitous in plants. To investigate the underlying mechanisms of this toxicity and bicarbonate (HCO)-dependent alleviation, wheat plants were hydroponically cultivated in half-strength Hoagland nutrient solution containing 7.5 mM NO (CK), 7.
View Article and Find Full Text PDFPlant Physiol Biochem
January 2024
School of Life Sciences, Guizhou Normal University, Guiyang 550025, China. Electronic address:
Submergence stress represents a serious threat to the yield and quality of maize because it can lead to oxygen deficiency and the accumulation of toxic metabolites. However, the mechanisms by which maize resists the adverse effects of submergence stress have yet to be fully elucidated. Here, we cloned a gene from maize Balem (Barley aleurone and embryo), ZmB12D, which was expressed at significant levels in seed embryos during imbibition and in leaves under submergence stress.
View Article and Find Full Text PDFJ Exp Bot
February 2024
Departamento de Biología Vegetal, Estación Experimental de Aula Dei, Consejo Superior de Investigaciones Científicas (CSIC), Avenida Montañana 1005, Zaragoza, and Unidad Asociada GBsC (BIFI-Unizar) al CSIC, Zaragoza, Spain.
Legume nodules express multiple leghemoglobins (Lbs) and non-symbiotic hemoglobins (Glbs), but how they are regulated is unclear. Here, we study the regulation of all Lbs and Glbs of Lotus japonicus in different physiologically relevant conditions and mutant backgrounds. We quantified hemoglobin expression, localized reactive oxygen species (ROS) and nitric oxide (NO) in nodules, and deployed mutants deficient in Lbs and in the transcription factors NLP4 (associated with nitrate sensitivity) and NAC094 (associated with senescence).
View Article and Find Full Text PDFJ Exp Bot
January 2024
National Institute for Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India.
A key feature in the establishment of symbiosis between plants and microbes is the maintenance of the balance between the production of the small redox-related molecule, nitric oxide (NO), and its cognate scavenging pathways. During the establishment of symbiosis, a transition from a normoxic to a microoxic environment often takes place, triggering the production of NO from nitrite via a reductive production pathway. Plant hemoglobins [phytoglobins (Phytogbs)] are a central tenant of NO scavenging, with NO homeostasis maintained via the Phytogb-NO cycle.
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