Project description:Aster yellows phytoplasma strain Hyd35 (16SrI-B) in micropropagated periwinkle shoots in collection was used to produce infected plants in pots that were separated according to the diverse symptomatology i.e. phyllody and witches’ broom. Small RNA high-throughput sequencing (HTS) was then used to determine the small RNA pattern of these plants. Bioinformatics analysis revealed the presence of expression changes of different miRNA classes and the presence of phytoplasma derived small RNAs. These results could complement previous studies and serve as a starting point for small RNA omics in phytoplasma research
Project description:The NJAY (New Jersey aster yellows) strain of 'Candidatus Phytoplasma asteris' is a significant plant pathogen responsible for causing severe lettuce yellows in the U.S. state of New Jersey. A draft genome sequence was prepared for this organism. A total of 177,847 reads were assembled into 75 contigs > 518 bp with a total base value of 652,092 and an overall [G+C] content of 27.1%. A total of 733 protein coding genes were identified. This Whole Genome Shotgun project has been deposited at DDBJ/ENA/GenBank under the accession MAPF00000000. This draft genome was used for genome- and gene-based comparative phylogenetic analyses with other phytoplasmas, including the closely related 'Ca. Phytoplasma asteris' strain, aster yellows witches'- broom (AY-WB). NJAY and AY-WB exhibit approximately 0.5% dissimilarity at the nucleotide level among their shared genomic segments. Evidence indicated that NJAY harbors four plasmids homologous to those known to encode pathogenicity determinants in AY-WB, as well as a chromosome-encoded mobile unit. Apparent NJAY orthologs to the important AY-WB virulence factors, SAP11 and SAP54, were identified. A number of secreted proteins, both membrane-bound and soluble, were encoded, with many bearing similarity to known AY-WB effector molecules and others representing possible secreted proteins that may be novel to the NJAY lineage.
Project description:Here, we report the draft genome sequence of a phytoplasma discovered in grapevine. The genome size is 600,116?nucleotides (nt), with 597 predicted open reading frames. It is most similar to a maize bushy stunt phytoplasma of group 16SrI-B (aster yellows). The possible presence of a 3,833-nt plasmid was also noted.
Project description:Aster yellows (AY) is an important disease of Brassica crops and is caused by Candidatus Phytoplasma asteris and transmitted by the insect vector, Aster leafhopper (Macrosteles quadrilineatus). Phytoplasma-infected Aster leafhoppers were incubated at various constant and fluctuating temperatures ranging from 0 to 35?°C with the reproductive host plant barley (Hordium vulgare). At 0?°C, leafhopper adults survived for 18 days, but failed to reproduce, whereas at 35?°C insects died within 18 days, but successfully reproduced before dying. Temperature fluctuation increased thermal tolerance in leafhoppers at 25?°C and increased fecundity of leafhoppers at 5 and 20?°C. Leafhopper adults successfully infected and produced AY-symptoms in canola plants after incubating for 18 days at 0-20?°C on barley, indicating that AY-phytoplasma maintains its virulence in this temperature range. The presence and number of AY-phytoplasma in insects and plants were confirmed by droplet digital PCR (ddPCR) quantification. The number of phytoplasma in leafhoppers increased over time, but did not differ among temperatures. The temperatures associated with a typical crop growing season on the Canadian Prairies will not limit the spread of AY disease by their predominant insect vector. Also, ddPCR quantification is a useful tool for early detection and accurate quantification of phytoplasma in plants and insects.
Project description:Transcriptional profiling of phytoplasma grown in plant (Chrysanthemum coronarium) and grown in insect (Macrosteles striifrons). Two-condition experiment, phytoplasma-infected plant and phytoplasma-infected insect. Biological replicates: 6 phytoplasma-infected plants and 6 phytoplasma-infected insects, independently grown and harvested. One replicate per array.
Project description:Aster Yellows phytoplasma (AYp; Candidatus Phytoplasma asteris) is associated with diseases of herbaceous plants, including ornamentals and important commercial vegetable and grain crops. The aster leafhopper (ALH; Macrosteles quadrilineatus Forbes) is the predominant vector of these bacteria, though other leafhopper species can acquire and transmit AYp. Potentially inoculative leafhoppers are reported to overwinter in the southern United States and migrate to northern latitudes in the spring. Examining the genetic similarities and differences in AYp associated with southern and northern populations of ALH may provide insight into the role that migrating ALH play in AYp disease development. To investigate similarities among geographically distinct populations of ALH and characterize the variation in AYp associated within these populations, we identified genetic variations in subgroup designation and the relative proportions of secreted AY-WB proteins from field-collected populations of AYp isolated from ALH from select locations in the southern (Arkansas, Kansas, Oklahoma, and Texas) and the northern United States (Wisconsin) in 2016, 2017, and 2018. Isolated phytoplasma were tested for variation of AYp genotypes, numbers of potentially inoculative (AYp-positive) ALH, and presence of specific AYp virulence (effector) genes. Geographically distinct populations of ALH collected in northern and southern regions were similar in CO1 genotype but carried different proportions of AYp genotypes. While similar AYp strains were detected in geographically distinct locations, the proportion of each genotype varied over time.