title: Differential expression of acid invertase genes in roots of metallicolous and non-metallicolous populations of Rumex japonicus under copper stress.
abstract: Recent evidence indicates that during copper (Cu) stress, the roots of metallicolous plants manifest a higher activity of acid invertase enzymes, which are rate-limiting in sucrose catabolism, than non-metallicolous plants. To test whether the higher activity of acid invertases is the result of higher expression of acid invertase genes, we isolated partial cDNAs for acid invertases from two populations of Rumex japonicus (from metalliferous and non-metalliferous soils), determined their nucleotide sequences, and designed primers to measure changes in transcript levels during Cu stress. We also determined the growth of the plants' roots, Cu accumulation, and acid invertase activities. The seedlings of R. japonicus were exposed to control or 20 μM Cu(2+) for 6d under hydroponic conditions. The transcript level and enzyme activity of acid invertases in metallicolous plants were both significantly higher than those in non-metallicolous plants when treated with 20 μM. Under Cu stress, the root length and root biomass of metallicolous plants were also significantly higher than those of non-metallicolous plants. The results suggested that under Cu stress, the expression of acid invertase genes in metallicolous plants of R. japonicus differed from those in non-metallicolous plants. Furthermore, the higher acid invertase activities of metallicolous plants under Cu stress could be due in part to elevated expression of acid invertase genes.
authors.affiliation: School of Resource and Environmental Sciences, Wuhan University, Wuhan, Hubei 430079, People's Republic of China.
authors.forename: Wu-Xing
authors.initials: WX
authors.lastname: Huang
authors.forename: Yi
authors.initials: Y
authors.lastname: Cao
authors.forename: Li-Juan
authors.initials: LJ
authors.lastname: Huang
authors.forename: Cong
authors.initials: C
authors.lastname: Ren
authors.forename: Zhi-Ting
authors.initials: ZT
authors.lastname: Xiong
mesh_terms: D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D003300:Copper / Q000633:toxicity*; D015870:Gene Expression / Q000187:drug effects; D008969:Molecular Sequence Data; D018517:Plant Roots / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D031804:Rumex / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D012989:Soil Pollutants / Q000633:toxicity*; D013312:Stress, Physiological; D043324:beta-Fructofuranosidase / Q000235:genetics* / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D012989:Soil Pollutants; D003300:Copper; D043324:beta-Fructofuranosidase