Abstract
Nitrate is an essential nutrient for plants, and crops depend on its availability for growth and development, but its presence in agricultural soils is far from stable. In order to overcome nitrate fluctuations in soil, plants have developed adaptive mechanisms allowing them to grow despite changes in external nitrate availability. Nitrate can act as both nutrient and signal, regulating global gene expression in plants, and the root tip has been proposed as the sensory organ. A set of genome-wide studies has demonstrated several nitrate-regulated genes in the roots of many plants, although only a few studies have been carried out on distinct root zones. To unravel new details of the transcriptomic and proteomic responses to nitrate availability in a major food crop, a double untargeted approach was conducted on a transition zone-enriched root portion of maize seedlings subjected to differing nitrate supplies. The results highlighted a complex transcriptomic and proteomic reprogramming that occurs in response to nitrate, emphasizing the role of this root zone in sensing and transducing nitrate signal. Our findings indicated a relationship of nitrate with biosynthesis and signalling of several phytohormones, such as auxin, strigolactones, and brassinosteroids. Moreover, the already hypothesized involvement of nitric oxide in the early response to nitrate was confirmed with the use of nitric oxide inhibitors. Our results also suggested that cytoskeleton activation and cell wall modification occurred in response to nitrate provision in the transition zone.
Highlights
Nitrogen (N) is one of the most important minerals affecting plant growth, development, and production
RNA sequencing (RNA-Seq) was used to generate the transcriptomic profiles of the early response to NO3− in the selected portion of root
As tungstate is a nitrate reductase (NR) inhibitor, these results indicated that these genes do not respond directly to nitrate itself, but that their regulation relies on some nitrate assimilation products
Summary
Nitrogen (N) is one of the most important minerals affecting plant growth, development, and production. Nitrate is the major source of N for most plant species (Wang YY et al, 2012). Exceeding nitrate concentrations in drinking water may pose risks to young animals and human health, Abbreviations: BR, brassinosteroid; cPTIO, 2-(4-carboxyphenyl)- 4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide; DEGs, differentially expressed genes; FDR, false discovery rate; GO, Gene Ontology; IAA, indole-3-acetic acid; iTRAQ, isobaric tags for relative and absolute quantitation; LC-MS/MS, liquid chromatography tandem mass spectrometry; N, nitrogen; NO, nitric oxide; NR, nitrate reductase; qRT-PCR, quantitative reverse transcription PCR; RNA-Seq, RNA sequencing; RPKM, reads per kb per million; ROS, reactive oxygen species; SL, strigolactone; TZ, transition zone
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
