Project description:Apple is one of the most important fruits that is propagated vegetatively, facilitating frequent transmission of viruses. The causative agent of the apple rubbery wood disease, apple rubbery wood virus 2 (ARWV2), can infect apple and pear. The branches of ARWV2-infected, symptomatic trees are flexible due to the decreased lignification of the xylem. In this research, we reanalysed our sRNA HTS datasets to survey the presence of ARWV2 in Hungary. Validation of HTS using RT-PCR revealed infection in several cultivars. The following RT-PCR-based survey revealed the infection of 15 trees, including pear and quince, without showing any rubbery wood symptoms. Analysis of the sRNA datasets allowed us to profile the sRNA pattern of ARWV2-infected and non-infected trees, and characterise the differential expression pattern of vsiRNAs and miRNAs targeting the lignin biosynthetic pathway. The results confirmed that neither the symptoms nor the gene-expression changes in the ARWV2-infected trees can be directly correlated with the presence of the virus, which can explain its frequent latent presence. Its variable concentration, sequence, and the mixed-infection status of the trees, make difficult its reliable diagnostics, which, although it would be highly needed, could be achieved as a result of further research.
Project description:40mer probes were designed to detect plant viroids infection at the genus level. This microarray platform is able to detect a wide spectrum of all the 8 reported viroid genera, including 37 known plant viroid species. Viroid samples were extracted from infected plant hosts and plasmids. Total RNA was extracted and hybridized to the microarray.
Project description:In order to analyze the production of small RNA (sRNA) by viroids upon infecting the plants, the tomato plants (Lycopersicum esculentum cv. Rutgers) were inoculated with the variants of Potato spindle tuber viroid (PSTVd). After 21-days of post inoculation, total RNA was extracted and subjected for deep-sequencing using Illumina platform. The primers were trimmed and only 21- to 24-nt long small RNAs were filtered after quality check of the raw data. The filtered 21- to 24-nt was mapped against the genomic and antigenomic strands of the respective PSTVd variants using standard pattern matching algorithm. The profiling of viroid derived sRNA (vd-sRNA) revealed that the viroids are susceptible to host RNA silencing mechanism. Evaluation of the vd-sRNA production in PSTVd infected tomato plants by high-throughput sequencing of small RNAs.
Project description:Using a high-throughput sequencing approach we quantitatively analyzed the content of viroid-derived siRNAs of an infected tree. Our results show that the entire PLMVd genome is found in the siRNA population. Also both polarities are susceptible to be targeted by the RNAi machinery but specific regions for each polarity are over represented. Those regions, that are not the same for each polarity, do not necessarily correlate with double stranded regions that could be substrate for Dicer-like enzymes. Finally the analysis of the first 5’ nucleotide revealed a bias toward a C or a U in viroid-derived siRNAs, indicating that at least AGO5 and AGO1 can recruit these small RNAs. Analysis of siRNAs population from RNA sample isolated from a viroid-infected tree
Project description:Winter dormancy is an adaptative mechanism that temperate and boreal trees have developed to protect their meristems against low temperatures. In apple trees (Malus domestica), cold temperatures induce bud dormancy at the end of summer/beginning of the fall. Apple buds stay dormant during winter until they are exposed to a period of cold, after which they can resume growth (budbreak) and initiate flowering in response to warm temperatures in spring. It is well-known that small RNAs modulate temperature responses in many plant species, but however, how small RNAs are involved in genetic networks of temperature-mediated dormancy control in fruit tree species remains unclear. Here, we have made use of a recently developed ARGONAUTE (AGO)-purification technique to isolate small RNAs from apple buds. A small RNA-seq experiment resulted in the identification of small RNAs that change their pattern of expression in apple buds during dormancy.
Project description:miRNAs are key players in multiple biological processes, therefore analysis and characterization of these small regulatory RNAs is a critical step towards better understanding of animal and plant biology. In apple (Malus domestica) two hundred microRNAs are known, which most probably represents only a fraction of miRNAome diversity. As a result, more effort is required to better annotate miRNAs and their functions in this economically important species. We performed deep sequencing of twelve small RNA libraries obtained for fire blight resistant and fire blight sensitive trees. In the sequencing results we identified 116 novel microRNAs and confirmed a majority of previously reported apple miRNAs. We then experimentally verified selected candidates with RT-PCR and stem-loop qPCR and performed differential expression analysis. Finally, we identified and characterized putative targets of all known apple miRNAs. In this study we considerably expand the apple miRNAome by identifying and characterizing dozens of novel microRNAs. Moreover, our data suggests that apple microRNAs might be considered as regulators and markers of fire blight resistance. Actively-growing shoot tip tissue samples were collected from twelve apple trees, which includes three biological replicates of each following scion-rootstock combinations: B.9, G.30, M.111 and M.27.
Project description:The purpose of this project is to examine the effects of rootstocks on the gene expression patterns in scions of apple trees. Gene expression patterns were examined in the Gala variety grafted onto seven different, commonly used rootstocks. These trees were grown in the greenhouse to limit environmental effects. Also, gene expression profiles were examined in three different varieties (Ambrosia, Melrose,and Gala) grafted onto B.9 rootstocks grown in the field. Keywords: apple, rootstock, graft, scion
Project description:miRNAs are key players in multiple biological processes, therefore analysis and characterization of these small regulatory RNAs is a critical step towards better understanding of animal and plant biology. In apple (Malus domestica) two hundred microRNAs are known, which most probably represents only a fraction of miRNAome diversity. As a result, more effort is required to better annotate miRNAs and their functions in this economically important species. We performed deep sequencing of twelve small RNA libraries obtained for fire blight resistant and fire blight sensitive trees. In the sequencing results we identified 116 novel microRNAs and confirmed a majority of previously reported apple miRNAs. We then experimentally verified selected candidates with RT-PCR and stem-loop qPCR and performed differential expression analysis. Finally, we identified and characterized putative targets of all known apple miRNAs. In this study we considerably expand the apple miRNAome by identifying and characterizing dozens of novel microRNAs. Moreover, our data suggests that apple microRNAs might be considered as regulators and markers of fire blight resistance.
Project description:Closed terminal buds of apple trees (Malus x domestica Borkh, Royal Gala and Castel Gala varieties) grown in commercial orchards were harvested during autumn and winter and exposed to cold treatments
Project description:We performed Illumina sequencing of sRNA libraries prepared from juvenile and reproductive phase buds from the apple trees. A large number of sRNAs exemplified by 33 previously annotated miRNAs and 6 novel members displayed significant differential expression (DE) patterns in juvenile and reproductive stages. The study provides new insight into our understanding of fundamental mechanism of poorly studied phase transitions in apple and other woody plants and important resource for future in-depth research in the apple development.