Identification and Profiling of microRNAs and Their Target Genes in Tibetan Hulless Barley in Response to Barley Leaf Stripe (BLS) Infection

Background Tibetan hulless barley 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. Results Here, we compared the miRNA profiles before and after BLS in two Tibetan hulless barley genotypes: Z1141, a BLS-sensitive wild variety, and Kunlun14, a BLS-tolerant hybrid variety. A total of 36 conserved and 56 novel miRNAs were identified. Of these, 10 conserved and 10 novel miRNAs exhibited significantly changed expression between the normal and infected leaves of Kunlun14, respectively, while 3 conserved and 5 novel miRNAs exhibited significantly changed expression between the normal and infected leaves of Z1141, respectively. A total of 24 miRNAs were found in Z1141 and Kunlun14, and a further 546 putative target genes were predicted. Transcriptome sequencing analysis showed that among the 546 candidate genes, 131 had significant differences in expression between the normal and infected leaves of Kunlun14 and Z1141. Gene ontology, pathway, and Blast analyses indicated 10 candidate target genes that were involved in the barley disease resistance. These 10 candidate target genes may be regulated by 7 miRNAs. According to quantitative real-time PCR results, the 10 targets were negatively correlated with their corresponding miRNAs after infection with BLS. Conclusions The miRNAs and their target genes expressed in Tibetan hulless barley were identified and found to be associated with BLS resistance. Thus, these miRNAs and their target genes may be exploited via breeding programs or genetic engineering to improve BLS resistance in Tibetan hulless barley.

Genome Resource for Barley Leaf Stripe Pathogen Pyrenophora graminea

Pyrenophora graminea is the causative agent of barley leaf stripe disease. In this study, the strong pathogenic isolate QWC was used to generate DNA for Illumina sequencing. After assembly, its genome size was 42.5 Mb, consisting of 264 scaffolds, and a total of 10,376 genes was predicted. This is the first genome resource available for P. graminea. The genome sequences of P. graminea will accelerate the understanding interaction of P. graminea and barley.

Effect of several rhizobacteria strains on barley resistance against Pyrenophora graminea under field conditions

Summary The effect of Pseudomonas putida BTP1, Bacillus subtilis Bs2500, Bs2504, and Bs2508 strains on the incidence (I) and severity (S) of barley leaf stripe disease caused by Pyrenophora graminea was evaluated under field conditions. Three barley cultivars varying in resistance level were used. The resistance achieved in our study was long-lasting. P. putida BTP1 and Bs2508 were in general the most effective strains in reducing significantly both I and S of barley leaf stripe disease vis-a-vis three cultivars in two growing seasons 2013/2014. The disease was reduced up to 66% in Arabi Abiad treated with P. putida BTP1. The susceptible landrace cultivar Arabi Abiad exhibited a significant induction of resistance by Bs2508 and BTP1. However, the resistant cultivar Banteng did not exhibit significant further increase in resistance by these bacterial strains. The grain yield of bacterized plants artificially inoculated with P. graminea was not affected, except that of the cultivar Arabi Abiad treated with Bs2508 and Bs2504. Triggering of resistance by treating seeds with the bacterial strains would be of great value in agriculture, especially in case of barley infection by P. graminea at an early stage of plant development.