Identification of conserved and novel microRNAs that are responsive to heat stress in Brassica rapa

The species Brassica rapa includes various vegetable crops. Production of these vegetable crops is usually impaired by heat stress. Some microRNAs (miRNAs) in Arabidopsis have been considered to mediate gene silencing in plant response to abiotic stress. However, it remains unknown whether or what miRNAs play a role in heat resistance of B. rapa. To identify genomewide conserved and novel miRNAs that are responsive to heat stress in B. rapa, we defined temperature thresholds of non-heading Chinese cabbage (B. rapa ssp. chinensis) and constructed small RNA libraries from the seedlings that had been exposed to high temperature (46 °C) for 1 h. By deep sequencing and data analysis, we selected a series of conserved and novel miRNAs that responded to heat stress. In total, Chinese cabbage shares at least 35 conserved miRNA families with Arabidopsis thaliana. Among them, five miRNA families were responsive to heat stress. Northern hybridization and real-time PCR showed that the conserved miRNAs bra-miR398a and bra-miR398b were heat-inhibitive and guided heat response of their target gene, BracCSD1; and bra-miR156h and bra-miR156g were heat-induced and its putative target BracSPL2 was down-regulated. According to the criteria of miRNA and miRNA* that form a duplex, 21 novel miRNAs belonging to 19 miRNA families were predicted. Of these, four were identified to be heat-responsive by Northern blotting and/or expression analysis of the putative targets. The two novel miRNAs bra-miR1885b.3 and bra-miR5718 negatively regulated their putative target genes. 5′-Rapid amplification of cDNA ends PCR indicated that three novel miRNAs cleaved the transcripts of their target genes where their precursors may have evolved from. These results broaden our perspective on the important role of miRNA in plant responses to heat

Son exome files

<p>The Fastq files represent the raw exome data for the son. The BAM files are derived from the fastq files by aligning the reads using a Burrows-Wheeler Aligner (BWA). The BAM file (.bam) is the binary version of a tab-delimited text file that contains sequence alignment data. The BAM file index (.bai) provides fast random access to the BAM file. The compressed VCF file (.vcf.gz) describes variant calls of the data in text format.</p

SNPs from the Son’s exome data

<p>Summary of the most likely informative SNPs from the Son’s exome data as judged by their observed frequency in HapMap.</p

A deletion inferred from mismatching genotype data

<p>The genotypes observed for the Mother (M) and Daughter (D) in the range 41,092,148-41,101,972 of chromosome 2 are mutually incompatible (Mendelian Inheritance Errors, highlighted in red). Genotypes for the Father (F) are shown for reference. Heterozygous sites are highlighted in grey. The simplest explanation for the cluster of incompatible genotypes is the presence of a deletion in the Mother''s genome, inherited by the Daughter. Both Mother and Daughter are thus hemizygous in this region. Right panel: inferred genotypes, showing the deleted segment inherited from Mother (blue) and the phased haplotype inherited from Father (yellow).</p

23andMe SNPs for which SNPedia annotations are available

<p>Each file contains all SNPs in the individual matching an annotated SNP in SNPedia. SNPedia annotations contain a magnitude value (subjective measure of the importance of the potential phenotypical effect) and a phenotype description of the condition of particular genotype affects.</p

The tomato genome sequence provides insights into fleshy fruit evolution

Tomato (Solanum lycopersicum) is a major crop plant and a model system for fruit development. Solanum is one of the largest angiosperm genera1 and includes annual and perennial plants from diverse habitats. Here we present a high-quality genome sequence of domesticated tomato, a draft sequence of its closest wild relative, Solanum pimpinellifolium2, and compare them to each other and to the potato genome (Solanum tuberosum). The two tomato genomes show only 0.6% nucleotide divergence and signs of recent admixture, but show more than 8% divergence from potato, with nine large and several smaller inversions. In contrast to Arabidopsis, but similar to soybean, tomato and potato small RNAs map predominantly to gene-rich chromosomal regions, including gene promoters. The Solanum lineage has experienced two consecutive genome triplications: one that is ancient and shared with rosids, and a more recent one. These triplications set the stage for the neofunctionalization of genes controlling fruit characteristics, such as colour and fleshiness