Articles
Phenolic and miRNA response of resistant hop cultivar ‘Wye Target’ after inoculation with phytopathogenic fungus Verticillium nonalfalfae
Article number
1328_6
Pages
47 – 54
Language
English
Abstract
MicroRNAs (miRNAs) are small non-coding RNAs of 20-24 nucleotides in length which repress gene expression by complementary binding and cleavage of mRNA transcripts.
They are involved in the regulation of biotic and abiotic stress responses of plants.
To date, little is known about the miRNAs of hops (Humulus lupulus L.) and their role in the response to Verticillium nonalfalfae, the pathogen causing Verticillium wilt, a disease that threatens European hop production.
We determined the fungal colonization, phenolic response and identified differentially expressed miRNAs of hop cultivar ‘Wye Target’ in the early stages of the pathogenesis of Verticillium wilt.
Hop plants were artificially inoculated with the highly virulent strain T2, and samples of control and treated plants were taken 1-day post-inoculation.
The relative amount of fungi was determined by qPCR using T2-specific primers.
Selected phenolic compounds were quantified by HPLC-MS method.
We performed miRNA sequencing to characterize and determine the differentially expressed miRNAs.
Although we detected 16.1-fold higher relative amount of fungi in the roots compared to the stems, possibly due to the fact that after inoculation by root dipping, part of the fungal mass remains on the surface of the roots, we could not detect any changes in identified phenolic compounds, nor in the total phenolic content in the treated root samples.
Of 28 identified phenolic compounds in the stems, we detected a significant increase in the content of epigallocatechin derivatives and 5-p-cumaroylquinic acid by 1.65- and 2.57-fold, respectively.
In miRNA-Seq analysis we identified 658 miRNA candidates supported by the hop genome sequence, of which 123 miRNA candidates belong to 27 known miRNA families from miRBase.
Using RPKM values obtained with the NOISeq R package, we identified 7 known miRNA families and 100 hop-specific miRNA candidates that show differential expression between control and treated hop plants.
They are involved in the regulation of biotic and abiotic stress responses of plants.
To date, little is known about the miRNAs of hops (Humulus lupulus L.) and their role in the response to Verticillium nonalfalfae, the pathogen causing Verticillium wilt, a disease that threatens European hop production.
We determined the fungal colonization, phenolic response and identified differentially expressed miRNAs of hop cultivar ‘Wye Target’ in the early stages of the pathogenesis of Verticillium wilt.
Hop plants were artificially inoculated with the highly virulent strain T2, and samples of control and treated plants were taken 1-day post-inoculation.
The relative amount of fungi was determined by qPCR using T2-specific primers.
Selected phenolic compounds were quantified by HPLC-MS method.
We performed miRNA sequencing to characterize and determine the differentially expressed miRNAs.
Although we detected 16.1-fold higher relative amount of fungi in the roots compared to the stems, possibly due to the fact that after inoculation by root dipping, part of the fungal mass remains on the surface of the roots, we could not detect any changes in identified phenolic compounds, nor in the total phenolic content in the treated root samples.
Of 28 identified phenolic compounds in the stems, we detected a significant increase in the content of epigallocatechin derivatives and 5-p-cumaroylquinic acid by 1.65- and 2.57-fold, respectively.
In miRNA-Seq analysis we identified 658 miRNA candidates supported by the hop genome sequence, of which 123 miRNA candidates belong to 27 known miRNA families from miRBase.
Using RPKM values obtained with the NOISeq R package, we identified 7 known miRNA families and 100 hop-specific miRNA candidates that show differential expression between control and treated hop plants.
Publication
Authors
U. Kunej, J. Jakše, M.M. Petkovšek, N. Štajner
Keywords
Humulus lupulus, Verticillium nonalfalfae, pathogenesis, phenolic compounds, miRNA
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