Abstract
BackgroundAgronomic treatments such as the application of nitrogen fertilizer and topping (removal of the inflorescence and top leaves) cause substantial changes in plant metabolism. To explore these changes, we conducted comparative transcriptomic and metabolomic analyses of leaves collected from four positions along the stem on plants exposed to two nitrogen doses and with different numbers of leaves retained after topping in tobacco (Nicotiana tabacum).ResultsWe identified 13,330 unique differentially expressed genes and 32 differentially abundant metabolites. Through RNA-seq and WGCNA analyze, we constructed 2 co-expression networks (green and blue) highly correlation to N application and leaf number retained, predicted a hub gene NtGER3 may play an important role in N metabolism related to amino acid (cysteine) through CK pathway in tobacco leaves, NtARFs may participated in modulating the auxin signal and N in bottom leaves and NtRAP2.12 as key gene involved in N regulation by ethylene pathway. What’s more, our data prove C/N transformation and balance affect the “source – flow - sink” redistribution and remobilization in tobacco during growth and development process.ConclusionsOverall, this comparative transcriptomics study provides novel insight into the complex molecular mechanisms underlying plant responses to different levels of nitrogen application and the number of leaves remaining after topping in plants.
Highlights
IntroductionAgronomic treatments such as the application of nitrogen fertilizer and topping (removal of the inflorescence and top leaves) cause substantial changes in plant metabolism
Agronomic treatments such as the application of nitrogen fertilizer and topping cause substantial changes in plant metabolism
Measurement of different metabolites in tobacco leaves To unravel the relationship between N and amino acid metabolism, we measured the contents of 32 metabolites, such as total N, protein, amino acids and several polyamines (PAs) et al in tobacco plants (Supplementary Table 2)
Summary
Agronomic treatments such as the application of nitrogen fertilizer and topping (removal of the inflorescence and top leaves) cause substantial changes in plant metabolism. To explore these changes, we conducted comparative transcriptomic and metabolomic analyses of leaves collected from four positions along the stem on plants exposed to two nitrogen doses and with different numbers of leaves retained after topping in tobacco (Nicotiana tabacum). CKs mainly in the form of trans-zeatin-riboside (tZR) and trans-zeatin (tZ) function as the long-distance signals through xylem transport, genes involved in glutamate and glutamine biosynthesis are identified as potential targets of tZ regulation, which indicating a possible role of amino acids in the long-distance shoot-to-root N signalling [15, 16]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
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 call
