Small RNA discovery in the interaction between barley and the powdery mildew pathogen

Abstract

Background Plants encounter pathogenic and non-pathogenic microorganisms on a nearly constant basis. Small RNAs such as siRNAs and miRNAs/milRNAs influence pathogen virulence and host defense responses. We exploited the biotrophic interaction between the powdery mildew fungus, Blumeria graminis f. sp. hordei ( Bgh ), and its diploid host plant, barley ( Hordeum vulgare ) to explore fungal and plant sRNAs expressed during Bgh infection of barley leaf epidermal cells. Results RNA was isolated from four fast-neutron immune-signaling mutants and their progenitor over a time course representing key stages of Bgh infection, including appressorium formation, penetration of epidermal cells, and development of haustorial feeding structures. The Cereal Introduction (CI) 16151 progenitor carries the resistance allele Mla6 , while Bgh isolate 5874 harbors the AVR a6 avirulence effector, resulting in an incompatible interaction. Parallel Analysis of RNA Ends (PARE) was used to verify sRNAs with likely transcript targets in both barley and Bgh. Bgh sRNAs are predicted to regulate effectors, metabolic genes, and translation-related genes. Barley sRNAs are predicted to influence the accumulation of transcripts that encode auxin response factors, NAC transcription factors, homeodomain transcription factors, and several splicing factors. We also identified phasing small interfering RNAs (phasiRNAs) in barley that overlap transcripts that encode receptor-like kinases (RLKs) and nucleotide-binding, leucine-rich domain proteins (NLRs). Conclusions These data suggest that Bgh sRNAs regulate gene expression in metabolism, translation-related, and pathogen effectors. PARE-validated targets of predicted Bgh milRNAs include both EKA (effectors homologous to AVR k1 and AVR a10 ) and CSEP (candidate secreted effector protein) families. We also identified barley phasiRNAs and miRNAs in response to Bgh infection. These include phasiRNA loci that overlap with a significant proportion of receptor-like kinases, suggesting an additional sRNA control mechanism may be active in barley leaves as opposed to predominant R -gene phasiRNA overlap in many eudicots. In addition, we identified conserved miRNAs, novel miRNA candidates, and barley genome mapped sRNAs that have PARE validated transcript targets in barley. The miRNA target transcripts are enriched in transcription factors, signaling-related proteins, and photosynthesis-related proteins. Together these results suggest both barley and ...

Correction to: small RNA discovery in the interaction between barley and the powdery mildew pathogen

“…Following the publication of the original article [1], the authors noted several typesetting errors which are noted in this Correction article.…”

Silencing Dicer-Like Genes Reduces Virulence and sRNA Generation in Penicillium italicum, the Cause of Citrus Blue Mold

“…The reason may be that the collected P. italicum samples were not at different developmental stages or at the infectious stage in the citrus fruit. It has been reported that Pt-sRNA can be especially accumulated in Penicillium triticina-infected wheat leaf tissue [48] and that a number of Blumeria graminis sRNAs were significantly differentially expressed at 0 to 48 h after inoculation in barley [18]. These findings reflect that internal needs or environmental stresses might form a feedback regulation mechanism to stimulate the accumulation of sRNAs in fungi or oomycetes.…”

Identification of MicroRNAs and Their Targets That Respond to Powdery Mildew Infection in Cucumber by Small RNA and Degradome Sequencing

“…The role of miRNAs in the PM response has been reported in wheat (Xin et al, 2010;Wu et al, 2015) and barely (Hunt et al, 2019), but the relationship between miRNAs and cucumber PM resistance is still not clear. The scanning electron microscopy results showed a higher density of PM hyphae on the leaf surface of D8 than on SSSL508-28 48 h after inoculation (Figure 1), which reflected their different responses to PM.…”

“…More recently, miRNAs related to the response of barley to PM (B. graminis f. sp. hordei) were putatively identified as regulating the transcript levels of transcription factors (TFs), such as auxin response factors, NAC [for NAM (no apical meristem), ATAF, CUC (cup-shaped cotyledon)], and homeodomains, as well as several splicing factors (Hunt et al, 2019).…”