Mi-1-Mediated Nematode Resistance in Tomatoes is Broken by Short-Term Heat Stress but Recovers Over Time (original) (raw)
Related papers
Crop Protection, 2013
Reproduction of Meloidogyne arenaria and Meloidogyne javanica on 12 tomato rootstocks and cultivars was tested to determine their relative resistance levels in a greenhouse with a non-temperature controlled environment. The nematode accumulated 754 and 719 degree-days (basal temperature 10 C) in Experiment 1 (Exp. 1) and Experiment 2 (Exp. 2), respectively, but heat accumulation occurred more rapidly in Exp. 1 (65 days post-inoculation, dpi) than in Exp. 2 (88 dpi). Soil temperatures above 28 C were recorded for 31 days during the experimental period in Exp. 1, and 20 days in Exp. 2. However, daily fluctuations in soil temperatures and intermittent peaks above 28 C did not compromise the resistance provided by the Mi-1 gene, and thus rootstocks Morgan, King-Kong, and Unifort consistently expressed a high resistant phenotype to M. arenaria and M. javanica. In contrast, rootstocks Multifort and Maxifort expressed reduced resistance levels. The reproduction rate of M. javanica was significantly higher (P < 0.05) than that of M. arenaria on the resistant and susceptible genotypes except for on the susceptible Motril in Exp. 1.
Fundamental and applied …, 1998
The effect of water (check), Hoagland solution (HS) withom nitrogen, or HS with N0 3 , NH 4 , or NH 4 N0 3 as nitrogen sources on growth of a resistant ("VFN-8") and a susceptible ("Rutgers") tomato cultivar and their responses to an aggressive (Experiments l and II) and nonaggressive (Experiments III and IV) Meloidogyne incognita population was tested at 24 and 28 oc. In each experiment, 40 one-week-old seedlings per cultivar per temperature were grown in 286 g sandy loam soil contained in styrofoam cups. Half of the seedlings in Experiments l and II were each inoculated with 1000 second-stage juveniles of the aggressive nematode population and in Experiments nI and IV with SOO nonaggressive population. All but Experiment III (J S days) lasted 28 days after nematode inoculation; at the end of which numbers and nematode developmental stages were determined. Both cultivars grew larger at 24 than at 28 oC and more so with NH 4 and NH 4 N0 3 treatments. Nematode infection levels were similar in the susceptible cultivar regardless of plant size; whereas, larger plants had fewer nematodes in the resistant cultivar. Both NH 4 and NH 4 N0 3 sources of nitrogen had fewer nematodes than N0 3 treatments in the resistant cultivar. Both nematode populations infected the resistant cultivar less than the susceptible cultivar, indicating that even if resistance breaks down, the process may be graduaI. Overall, the study shows that the source of nitrogen, in addition to temperature, is a factor in the break-down of the Mi-gene. The inverse relationship berween plant size and nematode infection in the resistant cultivar suggests that plant growth regulating (physiological) processes may be altering how the gene mediates resistance.
HortScience
The Mi gene, which is the only source of resistance to the root-knot nematodes M. incognita and M. javanica in tomatoes, is effective only at soil temperatures below 28C. This single dominant gene exists in a homozygous form in certain tomato cultivars, in a heterozygous form in others, and is lacking in others. It has also been introduced into heat-tolerant and heat-sensitive cultivars. The availability of such genotypes allows determining whether a) the homozygous form provides more resistance than the heterozygous form and b) heat tolerance protects the Mi gene at high-temperature stress. The results of in vitro tests using excised roots show that the resistance offered by the Mi gene in the homozygous or the heterozygous form to M. incognita and M. arenaria was the same. The presence of heat tolerance gene did not protect the Mi gene from losing its effectiveness above 28C.
Journal of Plant Protection Research, 2019
Resistance genes in response to root-knot nematode (Meloidogyne javanica) infection suppress one or more of several critical steps in nematode parasitism and their reproduction rate. The reaction of seven commercial tomato genotypes to M. javanica infection was investigated under greenhouse conditions. Current results classified these genotypes as: three resistant (Jampakt, Malika and Nema Guard), one moderately resistant (Fayrouz), and three susceptible (Castle Rock, Super Marmande and Super Strain B). Except Nema Guard, nematode infection significantly reduced plant height, fresh and dry weights of shoots of the other tomato genotypes. Leaf area was significantly reduced for all examined tomato genotypes except Malika and Nema Guard. Total chlorophyll was reduced in all tested tomato genotypes except Jampakt. Infection parameters of M. javanica and their population were significantly reduced on all nematode-resistant tomato genotypes compared to the susceptible genotypes. Also, th...
PLANT PHYSIOLOGY, 2006
Resistance conferred by the Mi-1 gene from Solanum peruvianum is effective and widely used for limiting root-knot nematode (Meloidogyne spp.) yield loss in tomato (Solanum lycopersicum), but the resistance is ineffective at soil temperatures above 28°C. Previously, we mapped the heat-stable resistance gene Mi-9 in Solanum arcanum accession LA2157 to the short arm of chromosome 6, in a genetic interval as Mi-1 and the Cladosporium fulvum resistance gene Cf2. We developed a fine map of the Mi-9 region by resistance and marker screening of an F2 population and derived F3 families from resistant LA2157 × susceptible LA392. Mi-1 intron 1 flanking primers were designed to amplify intron 1 and fingerprint Mi-1 homologs. Using these primers, we identified seven Mi-1 homologs in the mapping parents. Cf-2 and Mi-1 homologs were mapped on chromosome 6 using a subset of the F2. Cf-2 homologs did not segregate with Mi-9 resistance, but three Mi-1 homologs (RH1, RH2, and RH4) from LA2157 and one ...
Source of resistance to root-knot nematode (Meloidogyne javanica) in tomato cultivars
International Journal of Agricultural Technology, 2012
Nine tomato cultivars Redstone, Karoon, Falat CH, Falat 111, Efialto, Rutgers, Gina VF, Calj and Mobile were tested for their resistance to root-knot nematodes (Meloidogyne javanica) at inoculum levels of 0, 1000, 3000, 5000 juveniles (J2) per pot. Six cultivars found to be susceptible to varying degrees as egg masses were present in all with Rutgers being the most susceptible and also Falat CH, Redstone, Karoon, Mobile, Calj were susceptible while Efialto, Falat 111, Gina VF showed resistant reaction. The inoculums levels had a significant effect (P < 0.05) on the number of galls, egg mass, reproduction factor and plant weight. This factors and plant weight was negatively correlated with the highest gall numbers, egg mass, reproduction factor and lowest plant weights recorded at the highest inoculums level in all cultivars except in Efialto, Gina VF, Falat 111 in which there were little variation in gall numbers, egg mass, reproduction factor and plant weights. These cultivars c...
Tomato (Solanum lycopersicum) and root-knot nematodes (Meloidogyne spp.) – a century-old battle
Nematology, 2015
The encounter betweenMeloidogynespecies and tomato is many centuries old.Meloidogynespecies are known to cause high levels of economic loss worldwide in a multitude of agricultural crops, including tomato. This review was initiated to provide an overview of the damage potential ofMeloidogynespp. on cultivars of tomato (Solanum lycopersicum), and to compile the different studies done on the management ofMeloidogynespp. on tomato with particular emphasis on theMiresistance gene. Numerous studies have been conducted to assess the damage potential of root-knot nematode on various tomato cultivars; its yield loss potential ranges from 25 to 100%. A range of management options from using synthetic nematicides to soilless cultures have been tried and are available for managingMeloidogynespp. Resistant commercial cultivars and rootstocks carrying theMigene have been used successfully to manageMeloidogyne incognita,M. javanicaandM. arenaria. However, virulent populations have been detected. ...