Characterization of resistance to major tropical root-knot nematodes (Meloidogyne spp.) in solanum sisymbriifolium

Authors: HAJIHASSANI, ABOLFAZL - University Of Georgia; Rutter, William; SCHWARZ, TANNER - North Carolina State University; WOLDEMARIAM, MOGES - University Of Georgia; ALI, EMRAN - University Of Georgia; HAMIDI, NEGIN - University Of Georgia

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2019
Publication Date: 2/3/2020
Citation: Hajihassani, A., Rutter, W.B., Schwarz, T., Woldemariam, M.W., Ali, E., Hamidi, N. 2020. Characterization of resistance to major tropical root-knot nematodes (Meloidogyne spp.) in solanum sisymbriifolium. Phytopathology. 110:666-673. https://doi.org/10.1094/PHYTO-10-19-0393-R.
DOI: https://doi.org/10.1094/PHYTO-10-19-0393-R

Interpretive Summary: Root-knot nematodes (RKN, genus Meloidogyne) are a serious pest of tomato around the world. The most economical and environmentally friendly way for farmers to manage RKN in their fields is by planting resistant crop varieties. Unfortunately, there are very few commercially available tomato varieties that are resistant to RKN, and those that are available are not effective against all species of RKN in present in the Southeast. Solanum sisymbriifolium (aka litchi tomato) is a tomato relative that has been used as both a rotational trap crop as well as a tomato rootstock for grafting in order to control nematodes and other soil-borne pathogens in the Northwestern U.S. and Europe. Here we have performed greenhouse and micro-plot field experiments to assess the susceptibility of several litchi tomato lines to different species and isolates of RKN from the Southeastern U.S. Overall the litchi tomato lines performed very well, by showing a high level of resistance against most of the RKN species tested, including those species that are known to overcome commercial tomato resistance genes. These results provide evidence that litchi tomato could be an effective tool to help manage RKN in tomato production systems in the Southeast. Further study is needed to assess the utility of using litchi tomato as a root stock in the field.

Technical Abstract: The root-knot nematodes (Meloidogyne spp.) are an important contributor to the yield reduction in tomato. Though resistant cultivars to three common species (M. arenaria, M. incognita, and M. javanica) are available, they are not effective against other major species. Genotypes Cultivars of Solanum sisymbriifolium were examined to assess the presence and level of resistance to five major species. Differences in S. sisymbriifolium response to the nematode infection were apparent when susceptibility/resistance was classified by the egg counts per gram fresh weight of root and the multiplication rate of the nematodes. Genotype Cultivar Diamond was highly susceptible, Quattro and White Star susceptible, while Sis Syn II was resistant to M. arenaria race 1. Quattro, White Star and Sis Syn II exhibited a moderate to high level of resistance to M. incognita race 3 but the nematode increased 2.5-fold the initial population of the M. incognita on Diamond. All S. sisymbriifolium genotypes Cultivars were highly resistant to both M. haplanaria and M. enterolobii, while highly susceptible to M. javanica. A microplot study under field conditions using Sis Syn II confirmed that M. arenaria, M. incognita and M. haplanria were not pathogenic on the plant. Likewise, an examination on cross-sections of galled root tissues confirmed the susceptibility and resistance of S. sisymbriifolium genotypes to Meloidogyne spp. examined. Using S. sisymbriifolium as a resistant rootstock or a new source of resistance may result in the development of nonchemical and sustainable management strategies to protect the tomato crop.