title: Microcystin-LR-induced phytotoxicity in rice crown root is associated with the cross-talk between auxin and nitric oxide.
abstract: Irrigation with cyanobacterial-blooming water containing microcystin-LR (MC-LR) poses threat to the growth of agricultural plants. Large amounts of rice (Oryza sativa) field in the middle part of China has been irrigating with cyanobacterial-blooming water. Nevertheless, the mechanism of MC-LR-induced phytotoxicity in the root of monocot rice remains unclear. In the present study, we demonstrate that MC-LR stress significantly inhibits the growth of rice root by impacting the morphogenesis rice crown root. MC-LR treatment results in the decrease in IAA (indole-3-acetic acid) concentration as well as the expression of CRL1 and WOX11 in rice roots. The application of NAA (1-naphthylacetic acid), an IAA homologue, is able to attenuate the inhibitory effect of MC-LR on rice root development. MC-LR treatment significantly inhibits OsNia1-dependent NO generation in rice roots. The application of NO donor SNP (sodium nitroprusside) is able to partially reverse the inhibitory effects of MC-LR on the growth of rice root and the expression of CRL1 and WOX11 by enhancing endogenous NO level in rice roots. The application of NO scavenger cPTIO [2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethylinidazoline-1-oxyl-3-oxide] eliminates the effects of SNP. Treatment with NAA stimulates the generation of endogenous NO in MC-LR-treated rice roots. Treatment with NO scavenger cPTIO abolishes the ameliorated effect of NAA on MC-LR-induced growth inhibition of rice root. Treatment with SNP enhanced IAA concentration in MC-LR-treated rice roots. Altogether, our data suggest that NO acts both downstream and upstream of auxin in regulating rice root morphogenesis under MC-LR stress.
authors.affiliation: Institute of Food Quality and Safety, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
authors.forename: Hai-Qiang
authors.initials: HQ
authors.lastname: Zhang
authors.forename: Liang-Bin
authors.initials: LB
authors.lastname: Hu
authors.forename: Zhi-Qi
authors.initials: ZQ
authors.lastname: Shi
mesh_terms: D001947:Breeding; D005786:Gene Expression Regulation / Q000187:drug effects; D007210:Indoleacetic Acids / Q000378:metabolism*; D008387:Marine Toxins; D052998:Microcystins / Q000633:toxicity*; D009280:Naphthaleneacetic Acids / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D009599:Nitroprusside / Q000494:pharmacology; D012275:Oryza / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics; D018517:Plant Roots / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D013312:Stress, Physiological / Q000187:drug effects; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D007210:Indoleacetic Acids; D008387:Marine Toxins; D052998:Microcystins; D009280:Naphthaleneacetic Acids; D010940:Plant Proteins; D009599:Nitroprusside; D009569:Nitric Oxide; C034182:1-naphthaleneacetic acid; C057862:cyanoginosin LR
keywords: Auxin; Crown root; Microcystin-LR; Nitric oxide; Oryza sativa