Transcriptomic Profiling of Fruits from Pepper (Capsicum annuum L.), Variety Padrón (Mild Hot), at Two Ripening States ^†

Abstract

Pepper (Capsicum annuum L.) fruits are one of the most consumed vegetables worldwide. This produce has a great agro-economical relevance, since it is extensively cultivated. These fruits are characterized by their high content of vitamins C and A [1]. Capsicum annuum has many varieties, whose fruits differ in size, shape, color, and pungency, this last characteristic being due to the presence, in different degrees, of capsaicinoids and alkaloids, which are exclusive to the genus Capsicum [2]. The present study focuses on the transcriptomic profiling of an autochthonous Spanish variety called “Padrón” (mild hot) [3]. Pepper “Padrón” plants were grown in farms under the local conditions (42°44′05″ N 8°37′42″ W), and fruits at both green and red ripe ripening stages were collected. The transcriptome profiling was carried out in both types of fruits by RNA sequencing (RNA-seq) using the NextSeq550 system (Illumina^®) [4,5]. RNA-seq analysis revealed that the expression of more than half of the 17,499 identified transcripts was modulated during ripening. Comparing to green fruits, 5626 and 5241 genes were up- and down-regulated, respectively, in red fruits. These differentially expressed genes (DEGs) have been analyzed to determine the functional categories that orchestrate the ripening process at the genetic level of this non-climacteric fruit.