Two GCC boxes and AP2/ERF-domain transcription factor ORA59 in jasmonate/ethylene-mediated activation of the PDF1.2 promoter in Arabidopsis

Plant defense against microbial pathogens depends on the action of several endogenously produced hormones, including jasmonic acid (JA) and ethylene (ET). In defense against necrotrophic pathogens, the JA and ET signaling pathways synergize to activate a specific set of defense genes including PLANT DEFENSIN1.2 (PDF1.2). The APETALA2/Ethylene Response Factor (AP2/ERF)-domain transcription factor ORA59 acts as the integrator of the JA and ET signaling pathways and is the key regulator of JA- and ET-responsive PDF1.2 expression. The present study was aimed at the identification of elements in the PDF1.2 promoter conferring the synergistic response to JA/ET and interacting with ORA59. We show that the PDF1.2 promoter was activated synergistically by JA and the ET-releasing agent ethephon due to the activity of two GCC boxes. ORA59 bound in vitro to these GCC boxes and trans-activated the PDF1.2 promoter in transient assays via these two boxes. Using the chromatin immunoprecipitation technique we were able to show that ORA59 bound the PDF1.2 promoter in vivo. Finally, we show that a tetramer of a single GCC box conferred JA/ethephon-responsive expression, demonstrating that the JA and ET signaling pathways converge to a single type of GCC box. Therefore ORA59 and two functionally equivalent GCC box binding sites form the module that enables the PDF1.2 gene to respond synergistically to simultaneous activation of the JA and ET signaling pathways

Registro de imagens NOAA através de correlação de fase.

O objetivo deste estudo foi aplicar a técnica de correlação de fase nos dados do sensor AVHRR (Advanced Very High Resolution Radiometer), a bordo da série de satélites NOAA (National Oceanic Atmosferic Administration). Embora designadas para fins meteorológicos e oceanográficos que não demandam elevada precisão geométrica, as imagens AVHRR têm sido utilizadas para estudos temporais em terra, onde é fundamental a adoção de métodos de georreferenciamento automáticos e precisos.SBSR 2009

Identifying MicroRNAs and Transcript Targets in <i>Jatropha</i> Seeds

<div><p>MicroRNAs, or miRNAs, are endogenously encoded small RNAs that play a key role in diverse plant biological processes. <i>Jatropha curcas</i> L. has received significant attention as a potential oilseed crop for the production of renewable oil. Here, a sRNA library of mature seeds and three mRNA libraries from three different seed development stages were generated by deep sequencing to identify and characterize the miRNAs and pre-miRNAs of <i>J. curcas</i>. Computational analysis was used for the identification of 180 conserved miRNAs and 41 precursors (pre-miRNAs) as well as 16 novel pre-miRNAs. The predicted miRNA target genes are involved in a broad range of physiological functions, including cellular structure, nuclear function, translation, transport, hormone synthesis, defense<b>,</b> and lipid metabolism. Some pre-miRNA and miRNA targets vary in abundance between the three stages of seed development. A search for sequences that produce siRNA was performed, and the results indicated that <i>J. curcas</i> siRNAs play a role in nuclear functions, transport, catalytic processes and disease resistance. This study presents the first large scale identification of <i>J. curcas</i> miRNAs and their targets in mature seeds based on deep sequencing, and it contributes to a functional understanding of these miRNAs.</p></div

Data from reads of the sRNA database of mature <i>Jatropha curcas</i> seeds filtered with non-coding RNAs.

<p>*Total reads before filtering with non-coding and organellar small RNAs. The small RNAs were clustered according to their origin as follows: ribosome (rRNA), transporter (tRNA), small nuclear (snRNA), small nucleolar (snoRNA), mitochondrial (mtRNA) and chloroplastic (cpRNA).</p

Known miRNA families identified in mature <i>J. curcas</i> seeds.

<p>(<b>A</b>) The total number of miRNA members (isomiRNAs) from each miRNA family. (<b>B</b>) The number of total read counts of each miRNA family.</p

Targets of the miRNAs identified in mature seeds of <i>J. curcas</i>.

<p>The percentage (%) of contigs for each Gene Ontology (GO) term is relative to the total number of contigs from each gene category.</p

Total number of redundant and unique reads in the sRNA library of <i>J. curcas</i> mature seeds.

<p>(<b>A</b>) Data before filtering with non-coding RNAs and organelle RNAs. (<b>B</b>) Data after filtering with non-coding RNAs and organelle RNAs.</p

Raw data from sequencing <i>Jatropha curcas</i> sRNAs.

<p>Raw data from sequencing <i>Jatropha curcas</i> sRNAs.</p