Identification and characterization of mRNAs and lncRNAs of a barley shrunken endosperm mutant using RNA-seq

Barley shrunken endosperm mutants have been extensively reported. However, knowledge of the underlying molecular mechanisms of these mutants remains limited. Here, a pair of near isogenic lines (normal endosperm: Bowman and shrunken endosperm: sex1) was subjected to transcriptome analysis to identify mRNAs and lncRNAs related to endosperm development to further dissect its mechanism of molecular regulation. A total of 2123 (1140 up- and 983 down-regulated) unique differentially expressed genes (DEGs) were detected. Functional analyses showed that these DEGs were mainly involved in starch and sucrose metabolism, biosynthesis of secondary metabolites, and plant hormone signal transduction. A total of 343 unique target genes were identified for 57 differentially expressed lncRNAs (DE lncRNAs). These DE lncRNAs were mainly involved in glycerophospholipid metabolism, starch and sucrose metabolism, hormone signal transduction, and stress response. In addition, key lncRNAs were identified by constructing a co-expression network of the target genes of DE lncRNAs. Transcriptome results suggested that mRNA and lncRNA played a critical role in endosperm development. The shrunken endosperm in barley seems to be closely related to plant hormone signal transduction, starch and sucrose metabolism, and cell apoptosis. This study provides a foundation for fine mapping, elucidates the molecular mechanism of shrunken endosperm mutants, and also provides a reference for further studies of lncRNAs during the grain development of plants.