MicroRNAs (miRNAs) are a class of non-coding RNAs approximately 21-nt in length which play important roles in regulating gene expression in plants. Although many miRNA studies have focused on a few model plants, miRNAs and their target genes remain largely unknown in hot pepper (Capsicum annuum), one of the most important crops cultivated worldwide. We here employed high-throughput small-RNA and degradome sequencing to comprehensively identify small-RNAs and their targets in pepper. From these, we identified several novel targets of miRNAs, including the major de novo methylation enzyme involved in RNA-directed DNA methylation in plants. Furthermore, we identified several highly abundant 22-nt miRNA families that target conserved domains in NB-LRRs and trigger the production of phased secondary siRNAs. We showed that transient co-expression of can-miR482 with Rpi-blb1, one of the potato NB-LRRs, resulted in the attenuation of the hypersenstive responses in Nicotiana benthamiana, suggesting that interaction between miR-482 family and disease resistance proteins is likely to serve as a conserved trigger for defense mechanism in Solanaceae. This work provides the first reliable draft of the pepper small RNA transcriptome that offers an expanded picture of miRNAs in relation to NB-LRR regulation, providing a basis for understanding the functional roles of miRNAs in disease resistance pepper.

MicroRNAs (miRNAs) are a class of non-coding RNAs approximately 21-nt in length which play important roles in regulating gene expression in plants. Although many miRNA studies have focused on a few model plants, miRNAs and their target genes remain largely unknown in hot pepper (Capsicum annuum), one of the most important crops cultivated worldwide. We here employed high-throughput sequencing to comprehensively identify small RNAs and their targets in pepper. From these, we identified several novel targets of miRNAs, including the major de novo methylation enzyme involved in RNA-directed DNA methylation in plants. Furthermore, we identified several highly abundant 22-nt miRNA families that target conserved domains in NB-LRRs. We showed that transient co-expression of the miRNA with NB-LRRs, resulted in the attenuation of the hypersenstive responses in Nicotiana benthamiana, suggesting that interaction between miRNA family and disease resistance proteins is likely to serve as a conserved trigger for defense mechanism in Solanaceae. This work provides the first reliable draft of the small RNA transcriptome in pepper that offers an expanded picture of miRNAs in relation to NB-LRR regulation, providing a basis for understanding the functional roles of miRNAs in disease resistance.

Cabbage (Brassica oleracea) is one of the most important vegetable crops in the world. Yet, its sensitivity to cold stress, especially at the seedling stage, could limit the production. Until now, only, few studies about heritably durable cold tolerance were carried out in cabbage. Hence this study was done to characterize the transcriptome profiles of two cabbage genotypes with contrasting responses to cold stress using Illumina Hiseq short read (paired-end) sequencing technology. MicroRNAs (miRNAs) represent a class of short, non-coding, endogenous RNAs which play important roles in post-transcriptional regulation of gene expression. Thisstudy,wesoughttoprovideamorecomprehensivepredictionofB. oleracea cold responsive miRNAs based on high through put sequencing using two contrasting genotypes. The raw sequences were processed for removal of poor-quality and adaptor sequences. Then, the high quality unigenes (58,094) reads were applied for length filtering. Then, unigenes reads were used in a BLASTN search against of Rfam database and known miRNA database (miRBase 18.0) to removal of non-coding RNA’s and identifies conserved miRNA’s in B. oleracea. Further, novel reads were searched against B. oleracea genome. Their flanking sequences in the genome were used to predict their secondary structures, target prediction, and functional analysis. This is first report to identify novel miRNAs for cold stress through high throughput techniques. Our findings will provide an overview of potential miRNAs involved in cold stress, which may provide important clues on the function of miRNAs in from B. oleracea and other closely related Brassica species.