title: Transcriptome analysis reveals coordinated spatiotemporal regulation of hemoglobin and nitrate reductase in response to nitrate in maize roots.
abstract: Given the importance of nitrogen for plant growth and the environmental costs of intense fertilization, an understanding of the molecular mechanisms underlying the root adaptation to nitrogen fluctuations is a primary goal for the development of biotechnological tools for sustainable agriculture. This research aimed to identify the molecular factors involved in the response of maize roots to nitrate. cDNA-amplified fragment length polymorphism was exploited for comprehensive transcript profiling of maize (Zea mays) seedling roots grown with varied nitrate availabilities; 336 primer combinations were tested and 661 differentially regulated transcripts were identified. The expression of selected genes was studied in depth through quantitative real-time polymerase chain reaction and in situ hybridization. Over 50% of the genes identified responded to prolonged nitrate starvation and a few were identified as putatively involved in the early nitrate signaling mechanisms. Real-time results and in situ localization analyses demonstrated co-regulated transcriptional patterns in root epidermal cells for genes putatively involved in nitric oxide synthesis/scavenging. Our findings, in addition to strengthening already known mechanisms, revealed the existence of a new complex signaling framework in which brassinosteroids (BRI1), the module MKK2-MAPK6 and the fine regulation of nitric oxide homeostasis via the co-expression of synthetic (nitrate reductase) and scavenging (hemoglobin) components may play key functions in maize responses to nitrate.
authors.affiliation: Agricultural Biotechnology Department, University of Padua, Viale dell'Università 16, Legnaro, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Trevisan
authors.forename: A
authors.initials: A
authors.lastname: Manoli
authors.forename: M
authors.initials: M
authors.lastname: Begheldo
authors.forename: A
authors.initials: A
authors.lastname: Nonis
authors.forename: M
authors.initials: M
authors.lastname: Enna
authors.forename: S
authors.initials: S
authors.lastname: Vaccaro
authors.forename: G
authors.initials: G
authors.lastname: Caporale
authors.forename: B
authors.initials: B
authors.lastname: Ruperti
authors.forename: S
authors.initials: S
authors.lastname: Quaggiotti
mesh_terms: D054458:Amplified Fragment Length Polymorphism Analysis; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D006454:Hemoglobins; D050901:Nitrate Reductase / Q000235:genetics* / Q000378:metabolism*; D009566:Nitrates / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D003313:Zea mays / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*
chemical_list: D018076:DNA, Complementary; D006454:Hemoglobins; D009566:Nitrates; D012333:RNA, Messenger; D050901:Nitrate Reductase