Project description:This SuperSeries is composed of the following subset Series: GSE34110: Gene expression study after 3 days of cold exposure in a Solanum tuberosum cultivar called Desirée GSE34116: Gene expression study after 3 days of salt exposure in a Solanum tuberosum cultivar called Desirée Refer to individual Series
Project description:BackgroundWild potato Solanum bulbocastanum is a rich source of genetic resistance against a variety of pathogens. It belongs to a taxonomic group of wild potato species sexually isolated from cultivated potato. Consistent with genetic isolation, previous studies suggested that the genome of S. bulbocastanum (B genome) is structurally distinct from that of cultivated potato (A genome). However, the genome architecture of the species remains largely uncharacterized. The current study employed Diversity Arrays Technology (DArT) to generate a linkage map for S. bulbocastanum and compare its genome architecture with those of potato and tomato.ResultsTwo S. bulbocastanum parental linkage maps comprising 458 and 138 DArT markers were constructed. The integrated map comprises 401 non-redundant markers distributed across 12 linkage groups for a total length of 645 cM. Sequencing and alignment of DArT clones to reference physical maps from tomato and cultivated potato allowed direct comparison of marker orders between species. A total of nine genomic segments informative in comparative genomic studies were identified. Seven genome rearrangements correspond to previously-reported structural changes that have occurred since the speciation of tomato and potato. We also identified two S. bulbocastanum genomic regions that differ from cultivated potato, suggesting possible chromosome divergence between Solanum A and B genomes.ConclusionsThe linkage map developed here is the first medium density map of S. bulbocastanum and will assist mapping of agronomical genes and QTLs. The structural comparison with potato and tomato physical maps is the first genome wide comparison between Solanum A and B genomes and establishes a foundation for further investigation of B genome-specific structural chromosome rearrangements.
Project description:BackgroundMeloidogyne chitwoodi commonly known as Columbia root-knot nematode or CRKN is one of the most devastating pests of potato in the Pacific Northwest of the United States of America. In addition to the roots, it infects potato tubers causing internal as well as external defects, thereby reducing the market value of the crop. Commercial potato varieties with CRKN resistance are currently unavailable. Race specific resistance to CRKN has been introgressed from the wild, diploid potato species Solanum bulbocastanum into the tetraploid advanced selection PA99N82-4 but there is limited knowledge about the nature of its resistance mechanism. In the present study, we performed histological and differential gene expression profiling to understand the mode of action of introgressed CRKN resistance in PA99N82-4 in comparison to the CRKN susceptible variety Russet Burbank.ResultsHistological studies revealed that the nematode juveniles successfully infect both resistant and susceptible root tissue by 48 h post inoculation, but the host resistance response restricts nematode feeding site formation in PA99N82-4. Differential gene expression analysis shows that 1268, 1261, 1102 and 2753 genes were up-regulated in PA99N82-4 at 48 h, 7 days, 14 days and 21 days post inoculation respectively, of which 61 genes were common across all the time points. These genes mapped to plant-pathogen interaction, plant hormonal signaling, antioxidant activity and cell wall re-enforcement pathways annotated for potato.ConclusionThe introgressed nematode resistance in PA99N82-4 is in the form of both pattern-triggered immune response and effector-triggered immune response, which is mediated by accumulation of reactive oxygen species and hypersensitive response (HR). Salicylic acid is playing a major role in the HR. Polyamines and suberin (a component of the Casperian strip in roots) also play an important role in mediating the resistance response. The present study provides the first ever comprehensive insights into transcriptional changes among M. chitwoodi resistant and susceptible potato genotypes after nematode inoculation. The knowledge generated in the present study has implications in breeding for CRKN resistance in potato.
Project description:High throughput sequencing was used to investigate the production of small RNAs from cultivated tomato cultivar M82 and its wild relative Solanum pennellii. In order to understand the pattern of inheritance of the samll RNAs, interspecific hybrids (F1 and F2) along with series of introgressed lines comprising precise short genomic regions from S. pennellii in M82 background were used.