PREVALENCE AND CHARACTERIZATION OF PLANT-PARASITIC NEMATODES IN LOWLAND AND UPLAND RICE AGRO-ECOSYSTEMS IN LUZON, PHILIPPINES

  • M. L. D. Pascual 1 Nematology Research Unit, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium; 2 Cebu Technological University-Barili Campus, Barili, 6036 Cebu, Philippines
  • W. Decraemer Royal Belgian Institute of Natural Sciences, Vautierstraat 29, 1000 Brussels, Belgium
  • I. Tandingan De Ley Department of Nematology, University of California, Riverside, CA 92521, USA
  • A. Vierstraete Nematology Research Unit, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
  • H. Steel Nematology Research Unit, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
  • W. Bert Nematology Research Unit, Department of Biology, Ghent University, K.L. Ledeganckstraat 35, 9000 Ghent, Belgium
Keywords: D2D3, 18S, Hirschmanniella mucronata, Hirschmanniella oryzae, ITS, Meloidogyne graminicola, molecular phylogeny, morphology, morphometrics, rDNA. D2D3, Meloidogyne graminicola, filogenia mo

Abstract

The prevalence of plant-parasitic nematodes in lowland and upland rice ecosystems was compared based on soil and root samples from 30 rice fields in five provinces (Bataan, Batangas, Bulacan, Pampanga, and Pangasinan) of Luzon, Philippines. Five nematode genera (Meloidogyne, Hirschmanniella, Pratylenchus, Tylenchorhynchus, and Helicotylenchus) from lowland and nine genera (Rotylenchulus, Aphelenchoides, Criconematidae, Rotylenchus, and those found in lowland) from upland were identified. Meloidogyne graminicolawas the most prevalent and abundant plant-parasitic nematode in both ecosystems. Hirschmanniellawas the second most prevalent genus in lowland rice, but its density was low in upland rice. Pratylenchus was present in high densities, but was not widely distributed in either upland or lowland rice fields. The three most prevalent nematode species, M. graminicola, H. oryzae, and H. mucronata, were morphologically and molecularly characterized. Molecular analyses based on D2D3, ITS1-5.8-ITS2, and 18S rDNA regions generally showed an overall congruence, low intraspecific variation and agreement with classical morphological and morphometrical identifications.

Se comparó la prevalencia de nematodos parásitos de plantas en ecosistemas de arrozales en tierras bajas y altas, basados en muestras de suelo y raíces procedentes de 30 campos de arroz en cinco provincias (Bataan, Batangas, Bulacan, Pampanga, y Pangasinan) de Luzon, Filipinas. Se identificaron cinco géneros de nematodos (Meloidogyne, Hirschmanniella, Pratylenchus, Tylenchorhynchus, y Helicotylenchus) procedentes de arrozales en tierras bajas y nueve géneros procedentes de arrozales en tierras altas (Rotylenchulus, Aphelenchoides, Criconematidae, Rotylenchus, y aquellos encontrados en las tierras bajas). Meloidogyne graminicolafue el nematodo parásito de plantas más prevalente y abundante en ambos ecosistemas. Hirschmanniellafue el segundo género más prevalente en arrozales de tierras bajas, aunque sus densidades fueron bajas en tierras altas. Se encontraron Pratylenchusen altas densidades, pero no estaban ampliamente distribuidos ni en arrozales de tierras bajas ni de altas. Se caracterizaron morfológica y molecularmente las tres especies más prevalentes de nematodos parásitos de plantas, M. graminicola, H. oryzae, y H. mucronata. Análisis moleculares basados en las regiones D2D3, ITS1-5.8-ITS2, y 18S del rDNA mostraron congruencia, baja variación intraespecífica y estuvieron en concordancia con las clásicas identificaciones morfológicas y morfométricas.

Published
2014-02-01
Section
Articles