Publication Type

Journal Article

Journal Name

International Journal of Tropical Insect Science

Publication Date

6-1-2012

Abstract

Root-knot nematodes (RKN) are serious pests of tomato production in Kenya. Accurate identification of the plant parasitic nematodes is important for their effective management. A study conducted to assess their prevalence and identify RKN occurring on tomatoes in Central Kenya showed infestation of the crop in all the three districts. Of the total sampled plants (N = 900), the RKN infestation level ranged from 28 to 62%. RKN disease severity ranged from 2.5 to 5.3 in all the locations. Meloidogyne incognita, M. javanica and M. arenaria were the only species found infesting tomatoes in these areas. Female nematodes sampled from the symptomatic root system that had root galls characteristic of RKN were analysed by isozyme phenotypes of esterase (EST) and malate dehydrogenase (MDH). EST phenotype was polymorphic and enabled identification of the three different species, while MDH was monomorphic. Polymerase chain reaction-restriction fragment length polymorphism with region between mitochondrial cytochrome oxidase subunit II and large subunit ribosomal RNA (mtDNA COII-LSUrRNA) using HinfI showed that all isolates of M. incognita could be digested into three restriction fragments of about 1300, 400 and 100 bp, except for one species that showed an additional restriction site, giving four fragments of 900, 420, 380 and 100 bp. The 1800 bp PCR product of M. javanica was not digested by HinfI. Meloidogyne arenaria (EST phenotype A1) PCR product was digested into two restriction fragments of about 1700 and 100 bp, while M. arenaria (EST phenotype A2) had two restriction fragments at 1100 and 100 bp. © 2012 ICIPE.

Keywords

isozyme profiles, Meloidogyne spp, molecular identification, tomatoes

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