title: BnHO1, a haem oxygenase-1 gene from Brassica napus, is required for salinity and osmotic stress-induced lateral root formation.
abstract: In this report, a rapeseed (Brassica napus) haem oxygenase-1 gene BnHO1 was cloned and sequenced. It shared high homology with Arabidopsis HY1 proteins, and encodes a 32.6 kDa protein with a 54-amino-acid transit peptide, predicting the mature protein of 25.1 kDa. The mature BnHO1 expressed in Escherichia coli exhibits haem oxygenase (HO) activity. Furthermore, the application of lower doses of NaCl (10 mM) and polyethylene glycol (PEG) (2%) mimicked the inducible effects of naphthylacetic acid and the HO-1 inducer haemin on the up-regulation of BnHO1 and subsequent lateral root (LR) formation. Contrasting effects were observed when a higher dose of NaCl or PEG was applied. The above inducible and inhibitory responses were blocked significantly when the HO-1 inhibitor zinc protoporphyrin IX (ZnPPIX) or haemin was applied, both of which were reversed by the application of carbon monoxide or ZnPPIX, respectively. Moreover, the addition of ZnPPIX at different time points during LR formation indicated that BnHO1 might be involved in the early stages of LR formation. The auxin response factor transcripts and the auxin content in seedling roots were clearly induced by lower doses of salinity or osmotic stress. However, treatment with the inhibitor of polar auxin transport N-1-naphthylphthalamic acid prevented the above inducible responses conferred by lower doses of NaCl and PEG, which were further rescued when the treatments were combined with haemin. Taken together, these results suggested a novel role of the rapeseed HO-1 gene in salinity and osmotic stress-induced LR formation, with a possible interaction with auxin signalling.
authors.affiliation: College of Life Sciences, Cooperative Demonstration Laboratory of Centrifuge Technique, Nanjing Agricultural University and Beckman Coulter Ltd Co., Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Zeyu
authors.initials: Z
authors.lastname: Cao
authors.forename: Beibei
authors.initials: B
authors.lastname: Geng
authors.forename: Sheng
authors.initials: S
authors.lastname: Xu
authors.forename: Wei
authors.initials: W
authors.lastname: Xuan
authors.forename: Li
authors.initials: L
authors.lastname: Nie
authors.forename: Wenbiao
authors.initials: W
authors.lastname: Shen
authors.forename: Yongchao
authors.initials: Y
authors.lastname: Liang
authors.forename: Rongzhan
authors.initials: R
authors.lastname: Guan
mesh_terms: D000595:Amino Acid Sequence; D001663:Bilirubin / Q000494:pharmacology; D029688:Brassica napus / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*; D002248:Carbon Monoxide / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D051547:Heme Oxygenase-1 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006427:Hemin / Q000494:pharmacology; D007210:Indoleacetic Acids / Q000378:metabolism / Q000494:pharmacology; D008969:Molecular Sequence Data; D009280:Naphthaleneacetic Acids / Q000494:pharmacology; D009995:Osmosis / Q000187:drug effects; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D011092:Polyethylene Glycols / Q000494:pharmacology; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D054712:Salinity; D016415:Sequence Alignment; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics*
chemical_list: D007210:Indoleacetic Acids; D009280:Naphthaleneacetic Acids; D010940:Plant Proteins; D011994:Recombinant Proteins; C034182:1-naphthaleneacetic acid; D011092:Polyethylene Glycols; D012965:Sodium Chloride; D006427:Hemin; D002248:Carbon Monoxide; D051547:Heme Oxygenase-1; D001663:Bilirubin