A single nucleotide polymorphism in the promoter of a hairpin RNA contributes to Alternaria leaf spot resistance in apple (Malus × domestica Borkh.)
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ABSTRACT: Apple leaf spot caused by the Alternaria alternata f. sp. mali (ALT1) fungus is one of the most devastating diseases of apple (Malus × domestica). We identified a hairpin RNA (hpRNA)-mediated small RNAs, MdhpRNA277, from apple (cv. ‘Golden Delicious’) that is induced by infection with ALT1. MdhpRNA277 produces mdm-siR277-1 and mdm-siR277-2, which target five R genes, MdRNL1, MdRNL2, MdRNL3, MdRNL4, and MdRNL5, that are expressed at high levels in the resistant apple variety ‘Hanfu’ and at low levels in the susceptible variety ‘Golden Delicious’ following ALT1 infection. MdhpRNA277 is strongly induced in ‘Golden Delicious’ but was not induced in ‘Hanfu’ following ALT1 inoculation. The promoter activity of MdhpRNA277 was much stronger in ‘Golden Delicious’ than in ‘Hanfu’ after ALT1 inoculation. We identified a single nucleotide polymorphism (SNP) in the MdhpRNA277 promoter region between the susceptible variety ‘Golden Delicious’ (pMdhpRNA277-GD) and resistant variety ‘Hanfu’ (pMdhpRNA277-HF). The transcription factor MdWHy binds to pMdhpRNA277-GD, but not to pMdhpRNA277-HF. Transgenic ‘GL-3’ apple lines expressing pMdhpRNA277-GD: MdhpRNA277 were more susceptible to ALT1 infection than were those expressing pMdhpRNA277-HF:MdhpRNA277 due to induced mdm-siR277 accumulation and low levels of expression of the five target R genes. The failure of MdWHy to bind to pMdhpRNA277-HF might contribute to the low levels of MdhpRNA277 and mdm-siR277-1/-2 expression and the high levels of R gene expression and resistance to Alternaria leaf spot in resistant apple varieties. We confirmed that the SNP in pMdhpRNA277 is associated with Alternaria leaf spot resistance by analyzing the progeny of three additional crosses. The SNP identified in this study could be used as a marker to distinguish between apple varieties that are resistant or susceptible to Alternaria leaf spot.
Project description:This RNA-seq experiment captures expression data from challenged and mock-inoculated apple flowers (Malus domestica Golden Delicious) to assess the susceptible response of the primary infection court (48h) of apple by the fire blight pathogen Erwinia amylovora (CFBP 1430).
Project description:Investigation of whole genome gene expression level changes in leaves of apple seedlings (Golden delicious) 3 days after treatment by Bion 50WG (ASM) versus water.
Project description:The main objective of this analysis was to sequence the epigenome of the Apple (Malus domestica) doubled haploid 'Golden Delicious' tree. Our secondary objective was to identify differentially methylated regions between DNA purified from leaves and young fruits.
Project description:Investigation of whole genome gene expression level changes in leaves of apple seedlings (Golden delicious) 3 days after treatment by tomato cutin monomer extract (CME) versus formulation blank (FB). CME is a formulated extract enriched of hydroxy fatty acids from tomato cuticle
Project description:Russeting of apple fruit is a non-invasive physiological disorder. It occurs mainly in 'Golden Delicious' apple and its hybrids, while understanding of its molecular mechanism is still limited. In this study, we used mRNA sequencing and an isobaric tag for relative and absolute quantitation-based quantitative (iTRAQ) proteomic analysis to detect changes in the expression levels of genes and proteins during russeting formation in russeted and non-russeted skin of 'Golden Delicious' apple. We set up three comparison groups representing the three developmental stages in the russeting formation process. With the formation of fruit russeting, there were 2856 differentially expressed genes and 942 differentially expressed proteins in the comparison groups as detected at the transcript level and protein level, respectively. A correlation analysis of the transcriptome and proteome data revealed related-genes involved in lignin biosynthesis are significant changes at different developmental stages during apple russeting formation. Some other transcription factors, such as MYBs, NACs and LIMs were also involved in apple russeting formation. In this study, one LIM transcription factor was preliminarily determined to be involved in lignin biosynthesis by combining to PAL-box element. Studying the identified genes and proteins will provide further insights into the molecular mechanisms controlling apple russeting formation.
Project description:The main objective of this analysis was to sequence the epigenome of two apple (Malus domestica) doubled haploid 'Golden Delicious' fruits (GDDH13 and GDDH18). Our secondary objective was to identify differentially methylated regions between DNA purified from the GDDH13 genotype and the GDDH18 genotypes at two developmental stages.
Project description:Apple skin russeting naturally occurs in many varieties, particularly in 'Golden Delicious' and its pedigree, and is regarded as a non-invasive physiological disorder partly caused by excessive deposition of lignin. However, the understanding of its molecular mechanism is still limited. In this study, we used iTRAQ and RNA-seq to detect the changes in the expression levels of genes and proteins in three developmental stages of russeting formation, in russeted and non-russeted skin of 'Golden Delicious' apple. 2856 differentially expressed genes and 942 differentially expressed proteins in the comparison groups were detected at the transcript level and protein level, respectively. A correlation analysis of the transcriptomics and proteomics data revealed that four genes (MD03G1059200, MD08G1009200, MD17G1092400 and MD17G1225100) involved in lignin biosynthesis are significant changes during apple russeting formation. Additionally, 92 transcription factors, including 4 LIM transcription factors may be involved in apple russeting formation. Among them, one LIM transcription factor (MD15G1068200) was capable of binding to the PAL-box like (CCACTTGAGTAC) element, which indicated it was potentially involved in lignin biosynthesis. This study will provide further views on the molecular mechanisms controlling apple russeting formation.
Project description:Investigation of whole genome gene expression level changes in the youngest expanded leaves of open-pollinated Golden Delicious seedlings either sprayed with reverse osmosis water or acibenzolar-S-methyl (ASM). Treatment was performed by spraying sprayed to runoff (with a pressurized hand sprayer) with the commercial product Bion 50 WG (Syngenta, Basel, Switzerland; 50% of ASM) prepared in reverse osmosis water at a final concentration of 0.4 g/L. The youngest developped leaf of each seedling was sampled 3 days after the treatment.
Project description:Apple (Malus x domestica Borkh.) is a model fruit species to study the metabolic changes occurring at the onset of ripening as well the physiological mechanism governed by the hormone ethylene. In this survey, to dissect the climacteric interplay in apple, a multidisciplinary approach was employed. To this end, a comprehensive analysis of gene expression together with the investigation of several physiological entities (texture, volatilome and polyphenolic compounds) was carried out throughout fruit development and ripening. The transcriptomic profiling was conducted with two microarray platforms, a custom array dedicated to fruit ripening pathways (iRIPE) and a whole genome array specifically enriched of ripening related genes for apple (WGAA). The transcriptomic and phenotypic changes following the application of 1-methylcyclopropene (1-MCP), an ethylene inhibitor, were also highlighted. The suppression of ethylene modified and delayed the ethylene receptors turnover, leading to important modifications in the overall fruit physiology. The integrative comparative network analysis showed both negative and positive correlations between ripening related transcripts and accumulation of specific metabolites or texture components. The ripening distortion caused by the inhibition of the ethylene perception besides affecting the ethylene and texture control, stimulated the de-repression of auxin related genes, transcription factors and photosynthethic genes. In the end, the comprehensive repertoire of results obtained here step forwards in the elucidation of the multi-layered control of ethylene, hypothesizing a possible hormonal cross-talk coupled with a transcriptional regulation. 48 samples analyzed; 8 stages have been identified over the fruit development and ripening (from flower to post harvest ripening) of apple fruit belonging to two apple cultivars (Golden Delicious and Granny Smith), ending with 16 samples (3 replacates for each sample)