Molecular cloning and expression analysis of jasmonic acid dependent but salicylic acid independent LeWRKY1.

Various plant genes can be activated or inhibited by phytohormones under conditions of biotic and abiotic stress, especially in response to jasmonic acid (JA) and salicylic acid (SA). Interactions between JA and SA may be synergistic or antagonistic, depending on the stress condition. In this study, we cloned a full-length cDNA (LeWRKY1, GenBank accession No. FJ654265) from Lycopersicon esculentum by rapid amplification of cDNA ends. Sequence analysis showed that this gene is a group II WRKY transcription factor. Analysis of LeWRKY1 mRNA expression in various tissues by qRT-PCR showed that the highest and lowest expression occurred in the leaves and stems, respectively. In addition, LeWRKY1 expression was induced by JA and Botrytis cinerea Pers., but not by SA.

Computational identification of miRNAs and their targets in Phaseolus vulgaris.

MicroRNAs (miRNAs) are a class of non-coding small RNAs that negatively regulate gene expression at the post-transcriptional level. Although thousands of miRNAs have been identified in plants, limited information is available about miRNAs in Phaseolus vulgaris, despite it being an important food legume worldwide. The high conservation of plant miRNAs enables the identification of new miRNAs in P. vulgaris by homology analysis. Here, 1804 known and unique plant miRNAs from 37 plant species were blast-searched against expressed sequence tag and genomic survey sequence databases to identify novel miRNAs in P. vulgaris. All candidate sequences were screened by a series of miRNA filtering criteria. Finally, we identified 27 conserved miRNAs, belonging to 24 miRNA families. When compared against known miRNAs in P. vulgaris, we found that 24 of the 27 miRNAs were newly discovered. Further, we identified 92 potential target genes with known functions for these novel miRNAs. Most of these target genes were predicted to be involved in plant development, signal transduction, metabolic pathways, disease resistance, and environmental stress response. The identification of the novel miRNAs in P. vulgaris is anticipated to provide baseline information for further research about the biological functions and evolution of miRNAs in P. vulgaris.

Identification of miRNAs and their targets in wheat (Triticum aestivum L.) by EST analysis.

MicroRNAs (miRNAs) are a newly discovered class of noncoding small RNAs that regulate gene expression by directing target mRNA cleavage or translational inhibition. A large number of miRNAs have been identified in plants. Increasing evidence has shown that miRNAs play multiple roles in plant biological processes. So far, identification of miRNAs has been limited to a few model plant species, whose genomes have been sequenced. Wheat (Triticum aestivum L.) is one of the most important cereal crops worldwide. To date, only a few conserved miRNAs have been predicted in wheat. Here, we showed the conserved miRNAs identified in wheat by expressed sequence tag (EST) analysis. All previously known miRNAs from Arabidopsis, rice, and other plant species were used in a BLAST search against the wheat EST database to identify novel wheat miRNAs by a series of filtering criteria. By this strategy, we identified 62 conserved miRNAs, belonging to 30 miRNA families, 48 of which were newly discovered in wheat. These newly identified wheat miRNAs may regulate 287 potential targets, which are involved in development, signal transduction, metabolic pathways, disease resistance, ion transportation, and environmental stress response.