title: Aluminum triggers broad changes in microRNA expression  in rice roots.
abstract: MicroRNAs are small 21-nucleotide RNA molecules with  regulatory roles in development and in response to stress. Expression of some  plant miRNAs has been specifically associated with responses to abiotic  stresses caused by cold, light, iron, and copper ions. In acid soils, aluminum  solubility increases, thereby causing severe damage to plants. Although  physiological aspects of aluminum toxicity in plants have been well  characterized, the molecular mediators are not fully elucidated. There have been  no reports about miRNA responses to aluminum stress. Modulation of miRNA  expression may constitute a key element to explain the mechanisms implicated in  aluminum toxicity and tolerance. We examined the expression of at least one  miRNA member from each miRNA family in rice roots of Oryza sativa spp indica cv. Embrapa Taim and Oryza sativa spp japonica cv. Nipponbare  under high concentrations of aluminum. Forty-six miRNA families were  effectively detected by quantitative PCR. Among these, 13 were down-regulated  and six were up-regulated in roots of the Nipponbare cultivar after 8 h of  aluminum treatment. In roots of the Embrapa Taim cultivar, five miRNAs were  down-regulated and three were up-regulated. Analyses of their putative targets  suggest that these rice miRNAs are involved in the regulation of various metabolic  pathways in response to high concentrations of aluminum.
authors.affiliation: Laboratório de Genomas e Populações de Plantas, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil.
authors.forename: J C
authors.initials: JC
authors.lastname: Lima
authors.forename: R A
authors.initials: RA
authors.lastname: Arenhart
authors.forename: M
authors.initials: M
authors.lastname: Margis-Pinheiro
authors.forename: R
authors.initials: R
authors.lastname: Margis
mesh_terms: D000535:Aluminum / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics; D012275:Oryza / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism*; D018749:RNA, Plant / Q000096:biosynthesis* / Q000235:genetics; D013997:Time Factors
chemical_list: D035683:MicroRNAs; D018749:RNA, Plant; D000535:Aluminum