Arabidopsis

About: Arabidopsis is a research topic. Over the lifetime, 30944 publications have been published within this topic receiving 2181038 citations. The topic is also known as: Rockcress.

Novel and Stress-Regulated MicroRNAs and Other Small RNAs from Arabidopsis

Abstract: MicroRNAs (miRNAs) and short interfering RNAs (siRNAs) are small noncoding RNAs that have recently emerged as important regulators of mRNA degradation, translational repression, and chromatin modification. In Arabidopsis thaliana, 43 miRNAs comprising 15 families have been reported thus far. In an attempt to identify novel and abiotic stress regulated miRNAs and siRNAs, we constructed a library of small RNAs from Arabidopsis seedlings exposed to dehydration, salinity, or cold stress or to the plant stress hormone abscisic acid. Sequencing of the library and subsequent analysis revealed 26 new miRNAs from 34 loci, forming 15 new families. Two of the new miRNAs from three loci are members of previously reported miR171 and miR319 families. Some of the miRNAs are preferentially expressed in specific tissues, and several are either upregulated or downregulated by abiotic stresses. Ten of the miRNAs are highly conserved in other plant species. Fifty-one potential targets with diverse function were predicted for the newly identified miRNAs based on sequence complementarity. In addition to miRNAs, we identified 102 other novel endogenous small RNAs in Arabidopsis. These findings suggest that a large number of miRNAs and other small regulatory RNAs are encoded by the Arabidopsis genome and that some of them may play important roles in plant responses to environmental stresses as well as in development and genome maintenance.

The Arabidopsis Information Resource (TAIR): improved gene annotation and new tools

Abstract: The Arabidopsis Information Resource (TAIR, http://arabidopsisorg) is a genome database for Arabidopsis thaliana, an important reference organism for many fundamental aspects of biology as well as basic and applied plant biology research TAIR serves as a central access point for Arabidopsis data, annotates gene function and expression patterns using controlled vocabulary terms, and maintains and updates the A thaliana genome assembly and annotation TAIR also provides researchers with an extensive set of visualization and analysis tools Recent de- velopments include several new genome releases (TAIR8, TAIR9 and TAIR10) in which the A thaliana assembly was updated, pseudogenes and transposon genes were re-annotated, and new data from proteomics and next generation transcriptome sequencing were incorporated into gene models and splice variants Other highlights include progress on functional anno- tation of the genome and the release of sev- eral new tools including Textpresso for Arabidopsis which provides the capability to carry out full text searches on a large body of research literature

Regulation of Flowering Time and Floral Organ Identity by a MicroRNA and Its APETALA2-Like Target Genes

Abstract: MicroRNAs (miRNAs) are ∼21-nucleotide noncoding RNAs that have been identified in both animals and plants. Although in animals there is direct evidence implicating particular miRNAs in the control of developmental timing, to date it is not known whether plant miRNAs also play a role in regulating temporal transitions. Through an activation-tagging approach, we demonstrate that miRNA 172 (miR172) causes early flowering and disrupts the specification of floral organ identity when overexpressed in Arabidopsis. miR172 normally is expressed in a temporal manner, consistent with its proposed role in flowering time control. The regulatory target of miR172 is a subfamily of APETALA2 (AP2) transcription factor genes. We present evidence that miR172 downregulates these target genes by a translational mechanism rather than by RNA cleavage. Gain-of-function and loss-of-function analyses indicate that two of the AP2-like target genes normally act as floral repressors, supporting the notion that miR172 regulates flowering time by downregulating AP2-like target genes.

FT Protein Movement Contributes to Long-Distance Signaling in Floral Induction of Arabidopsis

Abstract: In plants, seasonal changes in day length are perceived in leaves, which initiate long-distance signaling that induces flowering at the shoot apex. The identity of the long-distance signal has yet to be determined. In Arabidopsis, activation of FLOWERING LOCUS T (FT) transcription in leaf vascular tissue (phloem) induces flowering. We found that FT messenger RNA is required only transiently in the leaf. In addition, FT fusion proteins expressed specifically in phloem cells move to the apex and move long distances between grafted plants. Finally, we provide evidence that FT does not activate an intermediate messenger in leaves. We conclude that FT protein acts as a long-distance signal that induces Arabidopsis flowering.