Two Brassica napus genes encoding NAC transcription factors are involved in response to high-salinity stress.
The NAC protein family is one of the novel classes of plant-specific transcription factors. In this study, two genes (BnNAC2 and BnNAC5) encoding the putative NAC transcription factors were identified in Brassica napus. Sequence analysis revealed that the deduced BnNAC proteins contain conserved N-terminal region (NAC domain) and highly divergent C-terminal domain. Yeast transactivation analysis showed that BnNAC2 could activate reporter gene expression, suggesting that BnNAC2 functions as a transcriptional activator. Quantitative RT-PCR analysis revealed that BnNAC2 was preferentially expressed in flowers, whereas BnNAC5 mRNAs accumulated at the highest level in stems. Further experimental results indicated that the two genes are high-salinity-, drought- and abscisic acid (ABA)-induced. Overexpression of BnNAC2 and BnNAC5 genes in yeast (Schizosaccharomyces pombe) remarkably inhibited the growth rate of the host cells, and enhanced the cells sensitive to high-salinity and osmotic stresses. Complementation test indicated that BnNAC5 could recover the defects such as salt-hypersensitivity and accelerated-leaf senescence of vni2 T-DNA insertion mutant. Several stress-responsive genes including COR15A and RD29A were enhanced in the complemented plants. These results suggest that BnNAC5 may perform the similar function of VNI2 in response to high-salinity stress and regulation of leaf aging.                 Key message                 BnNAC2 and BnNAC5 are salt-, drought- and ABA-induced genes. Overexpression of BnNAC5 in Arabidopsis                 vni2 mutant recovered the mutant defects (salt-hypersensitivity and accelerated-leaf senescence) to the phenotype of wild type.
Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan, 430079, China.
Hui
H
Zhong
Qian-Qian
QQ
Guo
Liang
L
Chen
Feng
F
Ren
Qing-Qing
QQ
Wang
Yong
Y
Zheng
Xue-Bao
XB
Li
D000040:Abscisic Acid / Q000494:pharmacology; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics; D001483:Base Sequence; D029688:Brassica napus / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D008353:Mannitol / Q000494:pharmacology; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010802:Phylogeny; D018515:Plant Leaves / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified; D054712:Salinity; D012568:Schizosaccharomyces / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D036226:Seedlings / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation
D000040:Abscisic Acid; D029681:Arabidopsis Proteins; D008353:Mannitol; D010940:Plant Proteins; D012965:Sodium Chloride; D014157:Transcription Factors; C570515:At5g13180 protein, Arabidopsis