@article{fraher_schwarz_heim_gesteira_mollinari_pereira_zeng_brown-guedira_gorny_yencho_2024, title={Discovery of a major QTL for resistance to the guava root-knot nematode (<i>Meloidogyne enterolobii</i>) in 'Tanzania', an African landrace sweetpotato (<i>Ipomoea batatas</i>)}, volume={137}, ISSN={["1432-2242"]}, DOI={10.1007/s00122-024-04739-1}, abstractNote={Sweetpotato, Ipomoea batatas (L.) Lam. (2n = 6x = 90), is among the world's most important food crops and is North Carolina's most important vegetable crop. The recent introduction of Meloidogyne enterolobii poses a significant economic threat to North Carolina's sweetpotato industry and breeding resistance into new varieties has become a high priority for the US sweetpotato industry. Previous studies have shown that 'Tanzania', a released African landrace, is resistant to M. enterolobii. We screened the biparental sweetpotato mapping population, 'Tanzania' x 'Beauregard', for resistance to M. enterolobii by inoculating 246 full-sibs with 10,000 eggs each under greenhouse conditions. 'Tanzania', the female parent, was highly resistant, while 'Beauregard' was highly susceptible. Our bioassays exhibited strong skewing toward resistance for three measures of resistance: reproductive factor, eggs per gram of root tissue, and root gall severity ratings. A 1:1 segregation for resistance suggested a major gene conferred M. enterolobii resistance. Using a random-effect multiple interval mapping model, we identified a single major QTL, herein designated as qIbMe-4.1, on linkage group 4 that explained 70% of variation in resistance to M. enterolobii. This study provides a new understanding of the genetic basis of M. enterolobii resistance in sweetpotato and represents a major step towards the identification of selectable markers for nematode resistance breeding.}, number={10}, journal={THEORETICAL AND APPLIED GENETICS}, author={Fraher, Simon and Schwarz, Tanner and Heim, Chris and Gesteira, Gabriel De Siqueira and Mollinari, Marcelo and Pereira, Guilherme Da Silva and Zeng, Zhao-Bang and Brown-Guedira, Gina and Gorny, Adrienne and Yencho, G. Craig}, year={2024}, month={Oct} }
 @article{kapoor_jenkins_schmutz_zhebentyayeva_kuelheim_coggeshall_heim_lasky_leites_islam-faridi_et al._2023, title={A haplotype-resolved chromosome-scale genome for Quercus rubra L. provides insights into the genetics of adaptive traits for red oak species}, ISSN={["2160-1836"]}, DOI={10.1093/g3journal/jkad209}, abstractNote={Abstract
               Northern red oak (Quercus rubra L.) is an ecologically and economically important forest tree native to North America. We present a chromosome-scale genome of Q. rubra generated by the combination of PacBio sequences and chromatin conformation capture (Hi-C) scaffolding. This is the first reference genome from the red oak clade (section Lobatae). The Q. rubra assembly spans 739 Mb with 95.27% of the genome in 12 chromosomes and 33,333 protein-coding genes. Comparisons to the genomes of Quercus lobata and Quercus mongolica revealed high collinearity, with intrachromosomal structural variants present. Orthologous gene family analysis with other tree species revealed that gene families associated with defense response were expanding and contracting simultaneously across the Q. rubra genome. Quercus rubra had the most CC-NBS-LRR and TIR-NBS-LRR resistance genes out of the 9 species analyzed. Terpene synthase gene family comparisons further reveal tandem gene duplications in TPS-b subfamily, similar to Quercus robur. Phylogenetic analysis also identified 4 subfamilies of the IGT/LAZY gene family in Q. rubra important for plant structure. Single major QTL regions were identified for vegetative bud break and marcescence, which contain candidate genes for further research, including a putative ortholog of the circadian clock constituent cryptochrome (CRY2) and 8 tandemly duplicated genes for serine protease inhibitors, respectively. Genome–environment associations across natural populations identified candidate abiotic stress tolerance genes and predicted performance in a common garden. This high-quality red oak genome represents an essential resource to the oak genomic community, which will expedite comparative genomics and biological studies in Quercus species.}, journal={G3-GENES GENOMES GENETICS}, author={Kapoor, Beant and Jenkins, Jerry and Schmutz, Jeremy and Zhebentyayeva, Tatyana and Kuelheim, Carsten and Coggeshall, Mark and Heim, Chris and Lasky, Jesse R. and Leites, Laura and Islam-Faridi, Nurul and et al.}, year={2023}, month={Sep} }
 @article{schwarz_li_yencho_pecota_heim_davis_2021, title={Screening Sweetpotato Genotypes for Resistance to a North Carolina Isolate of Meloidogyne enterolobii}, volume={105}, ISSN={0191-2917 1943-7692}, url={http://dx.doi.org/10.1094/PDIS-02-20-0389-RE}, DOI={10.1094/PDIS-02-20-0389-RE}, abstractNote={ Potential resistance to the guava root-knot nematode, Meloidogyne enterolobii, in 91 selected sweetpotato (Ipomoea batatas [L.] Lam.) genotypes was evaluated in six greenhouse experiments. Ten thousand eggs of M. enterolobii were inoculated on each sweetpotato genotype grown in a 3:1 sand to soil mixture. Sixty days after inoculation, the percentage of total roots with nematode-induced galls was determined, and nematode eggs were extracted from roots. Significant differences (P < 0.001) between sweetpotato genotypes were found in all six tests for gall rating, total eggs, and eggs per gram of root. Resistant sweetpotato genotypes were calculated as final eggs per root system divided by the initial inoculum, where Pf/Pi < 1 (reproduction factor; final egg count divided by initial inoculum of 10,000 eggs), and statistical mean separations were confirmed by Fisher’s least significant difference t test. Our results indicated that 19 out of 91 tested sweetpotato genotypes were resistant to M. enterolobii. Some of the susceptible genotypes included ‘Covington,’ ‘Beauregard,’ ‘NCDM04-001’, and ‘Hernandez.’ Some of the resistant sweetpotato genotypes included ‘Tanzania,’ ‘Murasaki-29,’ ‘Bwanjule,’ ‘Dimbuka-Bukulula,’ ‘Jewel,’ and ‘Centennial.’ Most of the 19 resistant sweetpotato genotypes supported almost no M. enterolobii reproduction, with <20 eggs/g root of M. enterolobii. A number of segregants from a ‘Tanzania’ × ‘Beauregard’ cross demonstrated strong resistance to M. enterolobii observed in the ‘Tanzania’ parent. In collaboration with North Carolina State University sweetpotato breeding program, several genotypes evaluated in these tests are being used to incorporate the observed resistance to M. enterolobii into commercial sweetpotato cultivars. }, number={4}, journal={PLANT DISEASE}, publisher={Scientific Societies}, author={Schwarz, Tanner R. and Li, Chunying and Yencho, G. Craig and Pecota, Kenneth V and Heim, Chris R. and Davis, Eric L.}, year={2021}, month={Apr}, pages={1101–1107} }