Global gene expression analysis of the response of physic nut (Jatropha curcas L.) to medium- and long-term nitrogen deficiency

Abstract

Jatropha curcas L. is an important biofuel plant with excellent tolerance of barren environments. However, studies on the regulatory mechanisms that operate in this plant in response to nitrogen (N) shortage are scarce. In this study, genome-wide transcriptional profiles of the roots and leaves of 8-week old physic nut seedlings were analyzed after 2 and 16 days of N starvation. Enrichment results showed that genes associated with N metabolism, processing and regulation of RNA, and transport predominated among those showing alterations in expression. Genes encoding transporter families underwent major changes in expression in both roots and leaves; in particular, those with roles in ammonia, amino acid and peptide transport were generally up-regulated after long-term starvation, while AQUAPORIN genes, whose products function in osmoregulation, were down-regulated. We also found that ASPARA−GINASE B1 and SARCOSINE OXIDASE genes were up-regulated in roots and leaves after 2 and 16 d N starvation. Genes associated with ubiquitination-mediated protein degradation were significantly up-regulated. In addition, genes in the JA biosynthesis pathway were strongly activated while expression of those in GA signaling was inhibited in leaves. We showed that four major classes of genes, those with roles in N uptake, N reutilization, C/N ratio balance, and cell structure and synthesis, were particularly influenced by long-term N limitation. Our discoveries may offer clues to the molecular mechanisms that regulate N reallocation and reutilization so as to maintain or increase plant performance even under adverse environmental conditions.

Quantitative trait loci mapping reveals important genomic regions controlling root architecture and shoot biomass under nitrogen, phosphorus, and potassium stress in rapeseed (Brassica napus L.)

“…BnaA09g40370D encoding a hypothetical protein and has been reported to regulate root growth and development in response to potassium deficiency ( Armengaud et al, 2010 ). Another gene ( BnaA09g40440D ) located at 40 Kb upstream from the peak position of the major QTL cluster qcA09-4 associated with root and biomass traits and has been reported that regulation nitrogen assimilation and utilization ( Kuang et al, 2017 ). Similarly, some important candidate genes were identified in the major QTL cluster qcC06-1 .…”

Effects of nitrogen levels on gene expression and amino acid metabolism in Welsh onion

“…NR is a key enzyme that catalyzes the first step of nitrate assimilation, and its reduced expression under nitrogen stress indicated the regulation of this enzyme in rice [ 25 ]. The down-regulated pattern was also detected in nitrogen-deficient physic nut [ 26 ]. In this study, NR expression showed a reducing trend related to nitrogen concentration, showing a similar regulation pattern in A. fistulosum.…”

Transcriptome Analysis of Gene Expression Patterns Potentially Associated with Premature Senescence in Nicotiana tabacum L.

“…The sudden rise at the last senescence period in the transcriptional levels of COX15 homologs, which act on the synthesis of heme A from heme B along with COX10 and as electron acceptor of the respiratory chain [ 80 ], implied its possible role in plant senescence [ 81 ], but it still remains elusive. The expression of uroporphyrinogen decarboxylase (DCUP) could be repressed under 16 d of N starvation [ 82 ], which was the key regulatory enzyme for synthesis of chlorophyll. Significant down-regulation in LA was found in our study.…”