Genomic markers linked to Meloidogyne chitwoodi resistance introgressed from Solanum bulbocastanum to cultivated potato and their utility in marker-assisted selection.

Meloidogyne chitwoodi is a major threat to potato production in the Pacific Northwest region of the United States. Infected tubers are rendered unmarketable; hence, growers' profitability is adversely affected. Breeding for nematode resistance is a long-term process and phenotyping the segregating populations for nematode resistance is the most time-consuming and laborious part of the process. Using DNA-based markers closely linked to the nematode resistance trait for marker-assisted selection (MAS) could enhance breeding efficiency and accuracy. In the present study, a pool of phenotyped progenies segregating for nematode resistance and susceptibility were fingerprinted using a 21 K single-nucleotide polymorphism (SNP) array. Eight candidate SNPs located on potato Chromosome 11, segregating with the nematode resistance trait, were identified and used as landmarks for discovery of other marker types such as simple sequence repeat (SSR) and insertion-deletion (INDEL) markers. Subsequently, a total of eight SNPs, 30 SSRs, and four INDELS located on scaffold 11 of Solanum bulbocastanum were used to design primers; markers were validated in a panel of resistant and susceptible clones. Two SNPs (SB_MC1Chr11-PotVar0066518 and SB_MC1Chr11-PotVar0064140), five SSRs (SB_MC1Chr11-SSR04, SB_MC1Chr11-SSR08, SB_MC1Chr11-SSR10, SB_MC1Chr11-SSR13, and SB_MC1Chr11-SSR20), and one INDEL (SB_MC1Chr11-INDEL4) markers showed polymorphism between the resistant and susceptible clones in the test panel and in other segregating progenies. These markers are robust, highly reproducible, and easy to use for MAS of nematode-resistant potato clones to enhance the breeding program. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-022-01285-w.

Correction to: Transcriptome profiling of resistance response to Meloidogyne chitwoodi introgressed from wild species Solanum bulbocastanum into cultivated potato.

Following the publication of this article [1], the authors noted an error in Figure 11.

Transcriptome profiling of resistance response to Meloidogyne chitwoodi introgressed from wild species Solanum bulbocastanum into cultivated potato.

BACKGROUND: Meloidogyne 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. RESULTS: Histological 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. CONCLUSION: The 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.