NO homeostasis is a key regulator of early nitrate perception and root elongation in maize.
Crop plant development is strongly dependent on nitrogen availability in the soil and on the efficiency of its recruitment by roots. For this reason, the understanding of the molecular events underlying root adaptation to nitrogen fluctuations is a primary goal to develop biotechnological tools for sustainable agriculture. However, knowledge about molecular responses to nitrogen availability is derived mainly from the study of model species. Nitric oxide (NO) has been recently proposed to be implicated in plant responses to environmental stresses, but its exact role in the response of plants to nutritional stress is still under evaluation. In this work, the role of NO production by maize roots after nitrate perception was investigated by focusing on the regulation of transcription of genes involved in NO homeostasis and by measuring NO production in roots. Moreover, its involvement in the root growth response to nitrate was also investigated. The results provide evidence that NO is produced by nitrate reductase as an early response to nitrate supply and that the coordinated induction of non-symbiotic haemoglobins (nsHbs) could finely regulate the NO steady state. This mechanism seems to be implicated on the modulation of the root elongation in response to nitrate perception. Moreover, an improved agar-plate system for growing maize seedlings was developed. This system, which allows localized treatments to be performed on specific root portions, gave the opportunity to discern between localized and systemic effects of nitrate supply to roots.
Department of Agriculture, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padua, Agripolis, Viale dell'Università, 16, 35020 Legnaro (PD), Italy.
Alessandro
A
Manoli
Maura
M
Begheldo
Andrea
A
Genre
Luisa
L
Lanfranco
Sara
S
Trevisan
Silvia
S
Quaggiotti
D064751:Ammonium Compounds / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant; D006454:Hemoglobins / Q000235:genetics; D006706:Homeostasis; D008954:Models, Biological; D050901:Nitrate Reductase / Q000235:genetics*; D009566:Nitrates / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism*; D009584:Nitrogen / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D015398:Signal Transduction; D012987:Soil / Q000737:chemistry; D003313:Zea mays / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology*
D064751:Ammonium Compounds; D006454:Hemoglobins; D009566:Nitrates; D010940:Plant Proteins; D012987:Soil; D009569:Nitric Oxide; D050901:Nitrate Reductase; D009584:Nitrogen
Maize; nitrate; nitrate reductase; nitric oxide; non-symbiotic haemoglobin; root; transition zone.