ABSTRACT
BACKGROUND: Root-knot nematodes (RKN, Meloidogyne spp.) are harmful phytophagous pests of Solanum spp. Some RKN species are becoming worldwide problems because of their virulence to RKN-resistant Solanum species. A new Solanum species carrying broad-spectrum resistance to Meloidogyne spp. is required for the effective management of this pest. Here we sought to determine the host suitability of RKN to Solanum palinacanthum, a wild Solanum species, and to evaluate its potential effectiveness in RKN management. RESULTS: We identified an RKN-resistant Solanum species, S. palinacanthum, by screening Solanum accessions. We tested its spectrum of resistance to common Meloidogyne spp. in Japan. In pot tests inoculated with second-stage juveniles, S. palinacanthum showed poor host suitability for Melidogyne incognita, M. arenaria genotypes A2-J and A2-O, M. javanica and M. hapla, indicating broad-spectrum resistance to RKN. The development of M. incognita within S. palinacanthum roots was significantly poorer than that in susceptible S. melongena and S. lycopersicum at 10 and 21 days after inoculation. Microplot tests confirmed that the number of second-stage juveniles in plots where S. palinacanthum grew and root galling of the root system were significantly lower than those of susceptible S. melongena, suggesting that the resistance could be used to manage RKN under field conditions. CONCLUSION: S. palinacanthum showed poor host suitability to all Meloidogyne spp. tested in this study, and it thus has the potential to be used as a genetic resource with broad-spectrum RKN resistance, and it could be effective against multiple RKN species in a field. © 2020 Society of Chemical Industry.
Subject(s)
Solanum , Tylenchoidea , Animals , Genotype , Japan , Plant Roots , Solanum/geneticsABSTRACT
A core collection of eggplant (Solanum melongena L.) was developed based on a dataset of genome-wide 831 SNP and 50 SSR genotypes analyzed in 893 accessions of eggplant genetic resources collected in the NARO Genebank using the Core Hunter II program. The 893 accessions were collected worldwide, mainly Asia. Genetic variation and population structure among the 893 eggplant accessions were characterized. The genetic diversity of the Asian accessions, especially the South Asian and Southeast Asian accessions, forming the center of diversity in eggplant, was higher than that of the other regions. The resulting core collection, World Eggplant Core (WEC) collection consisted of 100 accessions basically collected from the high genetic diversity countries. Based on the results of the cluster and STRUCTURE analyses with SNP genotypes, the WEC collection was divided into four clusters (S1-S4). Each cluster corresponds to a geographical group as below, S1; the European, American and African countries, S2; the East Asian countries, S3; the Southeast Asian countries, S4; the South Asian and Southeast Asian countries. The genotype and phenotype data of the WEC collection are available from the VegMarks database (https://vegmarks.nivot.affrc.go.jp/resource/), and seed samples are available from the NARO Genebank (https://www.gene.affrc.go.jp/databases-core_collections.php).
ABSTRACT
PREMISE OF THE STUDY: Twenty-seven nuclear microsatellite markers were developed for the mangrove fern, Acrostichum aureum (Pteridaceae), to investigate the genetic structure and demographic history of the only pantropical mangrove plant. METHODS AND RESULTS: Fifty-six A. aureum individuals from three populations were sampled and genotyped to characterize the 27 loci. The number of alleles and expected heterozygosity ranged from one to 15 and 0.000 to 0.893, respectively. Across the 26 polymorphic loci, the Malaysian population showed much higher levels of polymorphism compared to the other two populations in Guam and Brazil. Cross-amplification tests in the other two species from the genus determined that seven and six loci were amplifiable in A. danaeifolium and A. speciosum, respectively. CONCLUSIONS: The 26 polymorphic microsatellite markers will be useful for future studies investigating the genetic structure and demographic history of of A. aureum, which has the widest distributional range of all mangrove plants.
