Transcriptomic response of durum wheat to nitrogen starvation

Abstract

Nitrogen (N) is a key macronutrient representing a limiting factor for plant growth and development and affects productivity in wheat. In this study, durum wheat response to N chronic starvation during grain filling was investigated through a transcriptomic approach in roots, leaves/stems, flag leaf and spikes of cv. Svevo. Nitrogen stress negatively influenced plant height, tillering, flag leaf area, spike and seed traits, and total N content. RNA-seq data revealed 4,626 differentially expressed genes (DEGs). Most transcriptomic changes were observed in roots, with 3,270 DEGs, while 963 were found in leaves/stems, 470 in flag leaf, and 355 in spike tissues. A total of 799 gene ontology (GO) terms were identified, 180 and 619 among the upregulated and downregulated genes, respectively. Among the most addressed GO categories, N compound metabolism, carbon metabolism, and photosynthesis were mostly represented. Interesting DEGs, such as N transporters, genes involved in N assimilation, along with transcription factors, protein kinases and other genes related to stress were highlighted. These results provide valuable information about the transcriptomic response to chronic N stress in durum wheat, which could be useful for future improvement of N use efficiency.

Comparative analysis based on transcriptomics and metabolomics data reveal differences between emmer and durum wheat in response to nitrogen starvation

“…In durum wheat, the gene coding for nitrate reductase was up-regulated, while the genes orthologous to Arabidopsis glutamine synthetase and glutamate dehydrogenase family were down-regulated in response to N-starvation (Table S2). A similar result was reported by Curci et al . (2017) for the response of durum wheat leaves to N chronic starvation during grain filling.…”

“…In addition, the results of gene enrichment analysis indicate that emmer and durum wheat adapt to nitrogen starvation by a reprogramming of transcription. Transcription factors are important for controlling the expression of other genes in plant exposed to limited N condition or in complete starvation (Krapp et al ., 2011; Yang et al ., 2015; Curci et al ., 2017) and, accordingly, our results showed as the regulation of transcripts was highly different and, in some case, with an opposite trend between emmer and durum wheat. In addition, some GO categories were only enriched for the DEGs in durum wheat, such as: the cellular amino acids, oxoacid or organic acids metabolism which were also highlighted by Huang et al (2016) in their study on the transcriptomic evaluation in response to the imbalance of carbon: nitrogen ratio in rice seedling.…”

“…In an increasing number of model and crop species, transcriptome studies have highlighted the complexity of the regulatory mechanisms involved in the control of leaf or root gene expression under both N-limiting and non-limiting conditions (Krapp et al ., 2011; Humbert et al , 2013; Simons et al , 2014; Curci et al ., 2017). In addition, studies about the response of several cereal (e.g.…”

“…In addition, studies about the response of several cereal (e.g. rice, barley, sorghum, and wheat) to N starvation have highlighted differentially expressed genes (DEGs) involved in the response (Curci et al ., 2017; Zuluaga et al ., 2017; Yang et al ., 2015, Gelli et al ., 2014; Guo et al , 2014). For instance, Gelli et al (2014) compared transcriptomic levels in four tolerant and three sensitive sorghum genotypes to low N condition.…”

Preparation of uniformly labelled 13C- and 15N-plants using customised growth chambers

“…In the 13 C-experiment, 3.81 mol of 13 CO 2 were consumed which corresponds to a consumption rate of 11.5 mmol 13 CO 2 /g FW (Additional file 1: equation (S1, S4)). The consumed amounts of 15 N or 13 CO 2 are in good agreement with the literature (29)(30)(31).…”