Identification microRNAs and target genes in Tibetan hulless barley to BLS infection

Abstract

Tibetan hulless barley (Hordeum vulgare L. variety nudum Hook. f.) is widely grown on the Qinghai-Tibet Plateau, where it has served as a staple food for Tibetan people since the 5th century CE. Barley leaf stripe (BLS) is one of the most severe fungal diseases affecting the yield and quality of Tibetan hulless barley. Here, we compared the miRNA profiles before and after BLS in a BLS-sensitive (‘Z1141’) and tolerant (‘Kunlun14’) Tibetan hulless barley for the first time. A total of 36 conserved and 56 novel miRNAs were identified, of which 24 differentially expressed miRNAs were found in Z1141 and Kunlun14, and an additional 546 putative target genes were predicted. Transcriptome sequencing analysis showed that among these genes, 131 were differentially expressed in normal and infected leaves of Kunlun14 and Z1141. Gene ontology (GO), pathway, and Blast analyses indicated 10 candidate target genes including seven functional genes and three transcription factors were involved in barley disease resistance. These functional genes were two members of the CYP450 genes, a RGA gene, a LIN gene, a SAM gene, a PSD gene, and a NDB gene; the three transcription factor genes were all from the WRKY family. These 10 candidate target genes were regulated by eight miRNAs (hvu-miR168-3p, hvu-miR171-5p, hvu-miR159b, hvu-miR156a, hvu-novel-91, hvu-novel-46, hvu-novel-52, and hvu-novel-11). According to quantitative real-time polymerase chain reaction (PCR) results, the 10 targets were negatively correlated with their corresponding miRNAs after infection with BLS. Thus, these miRNAs and their target genes can be used to improve BLS resistance in Tibetan hulless barley though breeding programs or genetic engineering.