title: Uptake and phloem transport of glucose-fipronil conjugate in Ricinus communis involve a carrier-mediated mechanism.
abstract: Some compounds containing glucose are absorbed via the monosaccharide transporters of the plasma membrane. A glucose-fipronil conjugate, N-[3-cyano-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(trifluoromethyl)sulfinyl]-1H-pyrazol-5-yl]-1-(β-d-glucopyranosyl)-1H-1,2,3-triazole-4-methanamine (GTF), has been synthesized in our previous work. GTF exhibits moderate phloem mobility in Ricinus communis. In the current paper, we demonstrate that the uptake of GTF by Ricinus seedling cotyledon discs is partly mediated by an active carrier system (K(m)1 = 0.17 mM; V(max)1 = 2.2 nmol cm(-2) h(-1)). Four compounds [d-glucose, sucrose, phloridzin, and carbonyl cyanide m-chlorophenylhydrazone (CCCP)] were examined for their effect on GTF uptake. Phloridzin as well as CCCP markedly inhibit GTF uptake, and d-glucose weakly competes with it. The phloem transport of GTF in Ricinus seedlings is found to involve an active carrier-mediated mechanism that effectively contributes to the GTF phloem loading. The results prove that adding a glucose core is a reasonable and feasible approach to confer phloem mobility to fipronil by utilizing plant monosaccharide transporters.
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Ministry of Education, South China Agricultural University, Guangzhou, Guangdong, China.
authors.forename: Han-Xiang
authors.initials: HX
authors.lastname: Wu
authors.forename: Wen
authors.initials: W
authors.lastname: Yang
authors.forename: Zhi-Xiang
authors.initials: ZX
authors.lastname: Zhang
authors.forename: Ting
authors.initials: T
authors.lastname: Huang
authors.forename: Guang-Kai
authors.initials: GK
authors.lastname: Yao
authors.forename: Han-Hong
authors.initials: HH
authors.lastname: Xu
mesh_terms: D001692:Biological Transport; D002367:Ricinus communis / Q000378:metabolism*; D018548:Cotyledon / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D005960:Glucosides / Q000378:metabolism; D007306:Insecticides / Q000378:metabolism*; D008954:Models, Biological; D009004:Monosaccharide Transport Proteins / Q000378:metabolism; D052585:Phloem / Q000378:metabolism*; D011720:Pyrazoles / Q000378:metabolism*; D036226:Seedlings / Q000378:metabolism; D014230:Triazoles / Q000378:metabolism
chemical_list: D005960:Glucosides; D007306:Insecticides; D009004:Monosaccharide Transport Proteins; C570608:N-(3-cyano-1-(2,6-dichloro-4-(trifluoromethyl)phenyl)-4-((trifluoromethyl)sulfinyl)-1H-pyrazol-5-yl)-1-(beta-D-glucopyranosyl)-1H-1,2,3-triazole-4-methanamine; D011720:Pyrazoles; D014230:Triazoles; D005947:Glucose; C082360:fipronil