First Report of Meloidogyne haplanaria Infecting Mi-Resistant Tomato Plants in Florida and Its Molecular Diagnosis Based on Mitochondrial Haplotype

Abstract

Meloidogyne haplanaria is a species originally found infesting peanut in Texas and, more recently, in Arkansas. In this study, we confirmed the presence of M. haplanaria in Florida based on morphological and molecular characterization. This species was identified from a sample submitted for diagnosis collected from Mi-resistant tomato rootstock grown in Naples, FL. The major diagnostic criteria to distinguish M. haplanaria from other closely related root-knot nematode (RKN) species are based on morphological differences and host range tests, which are time consuming and labor intensive and require living or well-preserved specimens. In our study, we provide an easy diagnostic strategy to distinguish M. haplanaria from other RKN species based on amplification of two mitochondrial DNA regions. These regions span the intergenic spacer and part of the adjacent large subunit ribosomal RNA gene (lrDNA) and sequence polymorphisms in lrDNA revealed by the restriction pattern following digestion with the restriction enzymes HinfI and MnlI. A unique haplotype pattern, which has not been observed in any of the RKN species described thus far, was observed in M. haplanaria. The outcome of molecular analysis of M. haplanaria aligned with morphological measurement and characteristics as well as perineal pattern originally described for M. haplanaria.

Molecular characterization of root-knot nematodes (Meloidogyne spp.) from Arkansas, USA

“…Meloidogyne haplanaria (Texas peanut RKN) was originally found attacking peanut in Texas 29 and was also reported from Arkansas 17 and Mi -resistant tomato in Florida 30 . Host range studies revealed that it can parasitize several legumes and crucifer crops 29 and infect M. arenaria -susceptible cultivars of peanut, garden pea and radish 31 .…”

Texas Root-Knot Nematode Meloidogyne haplanaria Eisenback et al. 2003 (Nematoda: Chromadorea: Chromadoria: Rhabditida: Rhabditina: Tylenchomorpha: Meloidogynidae)

“…Host range studies revealed that Meloidogyne haplanaria can parasitize several legume and crucifer crops including peanut, garden pea, and radish (Eisenback et al 2003, Bendezu et al 2004. The Texas root-knot nematode was also reported in Florida causing serious damage to tomato cultivars that are resistant to other root-knot nematode species (Joseph et al 2016). Its host range is similar to several other root-knot nematode species and is likely to successfully parasitize a large and diverse number of hosts across a large range of plant families.…”

“…Texas root-knot nematode is not as widely distributed as some other root-knot nematodes such as Meloidogyne arenaria, Meloidogyne javanica, and Meloidogyne incognita. Since this nematode was first reported in Texas in 2003, it has been reported in Arkansas from tomato (Churamani et al 2015) and Florida from root-knotnematode-resistant tomato (Joseph et al 2016). Texas root-knot nematode has not been reported outside of the United States.…”

Resistant Pepper Carrying N, Me1, and Me3 have Different Effects on Penetration and Reproduction of Four Major Meloidogyne species

“…. Meloidogyne haplanaria, Eisenback, Bernard, Starr, Lee & Tomaszewski, a resistant (Mi gene)-breaking root-knot species of tomato, has also been reported to infect and reproduce on pepper (Eisenback et al, 2003;Bendezu et al, 2004;Joseph et al, 2016).…”

“…However, the levels of resistance in these lines have not been assessed against populations of M. arenaria race 1 and M. javanica from the Southern USA, and to our knowledge these resistance genes have never been assessed for their efficacy against M. haplanaria. Meloidogyne haplanaria is a recently described species from the southern USA that is known to overcome the widely used Mi gene in tomato, but has not been evaluated against resistance genes from other solonacious crops (Eisenback et al, 2003, Bendezu et al, 2004, Joseph et al, 2016. Due to the well documented hyper variability of the MIG species, and their ability to break resistance in pepper lines carrying the Me3 and N genes (Castagnone-Sereno et al, 2001;Thies, 2011, Bucki et al, 2017, it is imperative to continue assessing the existing resistant pepper lines against different populations and species of Meloidogyne.…”