the ankyrin (AnK) repeat protein family is largely distributed across plants and has been found to participate in multiple processes such as plant growth and development, hormone response, response to biotic and abiotic stresses. it is considered as one of the major markers of capsaicin content in pepper fruits. In this study, we performed a genome-wide identification and expression analysis of genes encoding AnK proteins in three Capsicum species: Capsicum baccatum, Capsicum annuum and Capsicum chinense. We identified a total of 87, 85 and 96 ANK genes in C. baccatum, C. annuum and C. chinense genomes, respectively. next, we performed a comprehensive bioinformatics analysis of the Capsicum ANK gene family including gene chromosomal localization, Cis-elements, conserved motif identification, intron/exon structural patterns and gene ontology classification as well as profile expression. phylogenetic and domain organization analysis grouped the Capsicum ANK gene family into ten subfamilies distributed across all 12 pepper chromosomes at different densities. Analysis of the expression of ANK genes in leaf and pepper fruits suggested that the ANKs have specific expression patterns at various developmental stages in placenta tissue. our results provide valuable information for further studies of the evolution, classification and putative functions of ANK genes in pepper. open Scientific RepoRtS | (2020) 10:4044 | https://doi.drought tolerance 19 , ABA-mediated regulation of reactive oxygen species levels under salt-stress 20 , and several plant diseases 21 , including those generated by fungus such as rice blast 22 . The release of genomic data and the development of bioinformatics analyses have led to comprehensive research on the identification and characterization of the ANK gene family in plants such as Arabidopsis 23 , rice 18 , tomato 24 , maize 25 , Physcomitrella patens 26 and soybean 27 . The number of ANK repeats, genes, and proteins in plants varies considerably across diverse plant species. In Arabidopsis thaliana, 509 ANK repeats encoded by 105 genes were reported, whereas rice contains 175 ANK repeat genes 18,23 .Pepper (Capsicum spp.) is a member of the Solanaceae family and is closely related to potato, tomato, eggplant, tobacco and petunia. Pepper represents an economically important horticultural crop worldwide because of its wide variety of uses, as a food, coloring agent, and spice and in pharmaceuticals, cosmetics and ornamental products as well as for its nutrimental value 28,29 . Despite the importance of pepper, genome-wide studies remain limited. The recent whole-genome sequencing of pepper 28 provided an excellent tool for genome-wide analysis for the identification and characterization of entire gene families present in this crop [30][31][32] . Recently, the ANK repeat domain was identified as one of the major markers linked to capsaicinoid synthesis in Capsicum annuum 33 and Capsicum chinense 34 .The present study aimed to analyze the gene locus and chromosome localization, protein length, ...

MicroRNAs (miRNAs) are regulators of the post-transcription stage of gene activity documented to play central roles in flower and fruit development in model plant species. However, little is known about their roles and differences in domesticated and wild Capsicum species. In this study, we used high-throughput sequencing to analyze the miRNA content at three developmental stages (flower, small fruit, and middle fruit) from two cultivated (C. baccatum and C. annuum) and two wild (C. chacoense and C. eximium) pepper species. This analysis revealed 22 known and 27 novel miRNAs differentially expressed across species and tissues. A number of stage- and species-specific miRNAs were identified, and Gene Ontology terms were assigned to 138 genes targeted by the miRNAs. Most Gene Ontology terms were for the categories “genetic information processing”, “signaling and cellular processes”, “amino acid metabolism”, and “carbohydrate metabolism”. Enriched KEGG analysis revealed the pathways amino acids, sugar and nucleotide metabolism, starch and sucrose metabolism, and fructose-mannose metabolism among the principal ones regulated by miRNAs during pepper fruit ripening. We predicted miRNA–target gene interactions regulating flowering time and fruit development, including miR156/157 with SPL genes, miR159 with GaMYB proteins, miR160 with ARF genes, miR172 with AP2-like transcription factors, and miR408 with CLAVATA1 gene across the different Capsicum species. In addition, novel miRNAs play an important role in regulating interactions potentially controlling plant pathogen defense and fruit quality via fructokinase, alpha-L-arabinofuranosidase, and aromatic and neutral amino acid transporter. Overall, the small RNA-sequencing results from this study represent valuable information that provides a solid foundation for uncovering the miRNA-mediated mechanisms of flower and fruit development between domesticated and wild Capsicum species.