• ISSN 1008-505X
  • CN 11-3996/S
LIANG Gui-hong, HUA Ying-peng, SONG Hai-xing, ZHANG Zhen-hua. CACTFTPPCA1 (YACT), Dof (AAAG) and MYB may be involved in the molecular response of Brassica napus to nitrogen stress[J]. Journal of Plant Nutrition and Fertilizers, 2020, 26(2): 338-353. DOI: 10.11674/zwyf.19112
Citation: LIANG Gui-hong, HUA Ying-peng, SONG Hai-xing, ZHANG Zhen-hua. CACTFTPPCA1 (YACT), Dof (AAAG) and MYB may be involved in the molecular response of Brassica napus to nitrogen stress[J]. Journal of Plant Nutrition and Fertilizers, 2020, 26(2): 338-353. DOI: 10.11674/zwyf.19112

CACTFTPPCA1 (YACT), Dof (AAAG) and MYB may be involved in the molecular response of Brassica napus to nitrogen stress

  • Objectives Oilseed rape requires high N supply whereas exhibits low N use efficiency (NUE). The allocation of N source and sink is considered the key factor controlling the NUE of plants. NRT1.7 gene in Arabidopsis mediates the re-transport process of phloem nitrates from senescent leaves to young leaves and horns. We identified and analyzed the expression of NRT1.7 gene in rapeseed, and studied their response to N levels.
    Methods NRT1.7 homologous genes in Brassica rapa, Brassica oleracea and Brassica napus were identified by bioinformatics with the basic sequences of AtNRT1.7, and were employed to predict and analyze some bioinformatical parameters of BnaNRT1.7s, including copy number, phylogenetic analysis, evolutionary selection pressure, molecular characteristics, conserved motifs, transmembrane domains, chromosome location, gene structures and the cis-acting elements binged in the promoter regions. Moreover, the expression pattern and gene expression response to nitrogen of BnaNRT1.7s were analyzed with the Real-time quantitative PCR detecting system (qRT-PCR). Seedlings of Brassica napus were used as materials in the N hydroponic experiment. The expression of NRT1.7 gene was determined after cultured in solution of NO3-N 9.0 mmol/L for 10 days; then transferred into solution of NO3-N 0.3 mmol/L for another 3 days (low-N stress), or into no N solution for another 3 days and then resupplied with NO3-N of 9.0 mmol/L for 6 h (N-starvation treatment).
    Results The identified BnaNRT1.7 gene family contained 6 members, all of them were in similar innovation process and distributed in the similar branch as Arabidopsis thaliana. The Ka/Ks of BnaNRT1.7s were lower than 0.3, indicating a strong purify selection was acting on the BnaNRT1.7s. All BnaNRT1.7s were stable and amphiphilic protein, which contained 12−13 transmembrane domains. The gene structures of BnaNRT1.7s were stable, which were disrupted by 3 introns. CACTFTPPCA1 (YACT), Dof (AAAG) and MYB were the most abundant cis-acting elements binding to the promoter regions of BnaNRT1.7s, which might be involved in the molecular response of plants to N nutrition. The qRT-PCR showed that the expression of NRT1.7 genes was regulated by different N levels. The expression of BnaA7.NRT1.7b and BnaC6.NRT1.7b genes in roots were up-regulated while BnaCn.NRT1.7 gene in shoots was inhibited by 72 h of N stress, which jointly regulated the rapeseed low-N tolerance. In N starvation treatment, the expression of BnaNRT1.7 genes were inhibited in both the shoots and roots. Geneco-expression network identified that BnaCn.NRT1.7 and BnaC6.NRT1.7b were the central members, which were proposed to play core roles in the phloem N remobilization of both the shoots and roots under limited N stresses, respectively.
    Conclusions The evolution of NRT1.7 proteins in oilseed rape are relatively conservative with stable gene structures, CACTFTPPCA1(YACT), Dof (AAAG) and MYB are bound to the promoter regions of BnaNRT1.7s, which may be involved in the molecular response of plants to N stress.
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