title: Nitric oxide is involved in hemin-induced cucumber adventitious rooting process.
abstract: Hemin, a heme oxygenase-1 (HO-1) inducer, was shown to exert numerous beneficial physiological functions in animals. Our previous study suggests that HO-1/carbon monoxide (CO) acts as a novel downstream signal system in the auxin-induced adventitious rooting. The objective of this study was to test whether nitric oxide (NO) is involved in hemin-induced cucumber adventitious rooting. Applications of hemin or CO aqueous solution to auxin-depleted cucumber explant induced up-regulation of cucumber HO-1 transcripts (CsHO1), NO production, and thereafter adventitious root formation, and some above responses were blocked by the combination treatment with two nitric oxide synthase (NOS)-like enzyme inhibitors N(G)-nitro-L-arginine methylester hydrochloride and N(G)-nitro-L-arginine, a HO-1 specific inhibitor zinc protoporphyrin IX, and a specific NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt. However, these blocking responses were not observed using tungstate, an inhibitor of nitrate reductase, another NO producing enzyme in plants. Furthermore, the guanylate cyclase inhibitors 1H-(1,2,4)-oxadiazole[4,3-a]quinoxalin-1-one and 6-anilino-5,8-quinolinedione reduced root development induced by hemin, whereas the cell-permeable cyclic guanosine monophosphate (cGMP) derivative 8-Br-cGMP reversed this effect. Together, our results indicated that at least in our experimental conditions, NO might operate downstream of hemin promoting adventitious root formation probably in a cGMP-dependent manner.
authors.affiliation: College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xuan
authors.forename: Sheng
authors.initials: S
authors.lastname: Xu
authors.forename: Meiyue
authors.initials: M
authors.lastname: Li
authors.forename: Bin
authors.initials: B
authors.lastname: Han
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Yuting
authors.initials: Y
authors.lastname: Lin
authors.forename: Jingjing
authors.initials: J
authors.lastname: Huang
authors.forename: Wenbiao
authors.initials: W
authors.lastname: Shen
authors.forename: Jin
authors.initials: J
authors.lastname: Cui
mesh_terms: D018553:Cucumis sativus / Q000187:drug effects* / Q000254:growth & development*; D004791:Enzyme Inhibitors; D006427:Hemin / Q000494:pharmacology*; D050901:Nitrate Reductase / Q000037:antagonists & inhibitors; D009569:Nitric Oxide / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects* / Q000254:growth & development*; D017973:Tungsten Compounds / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D017973:Tungsten Compounds; D009569:Nitric Oxide; D006427:Hemin; D050901:Nitrate Reductase; C045951:tungstate