One of the methods suitable for investigation of the genetic variability of plant-parasitic nematodes is the analysis of protein and, in particular, of enzyme polymorphism. Changes of gene sequences lead to the replacement of amino acids in proteins with a rearrangement of their size and net charge. Proteins can be separated according to their net charge by an electrophoretical technique called isoelectrofocusing in which a determined pH gradient is established on separation gels. Additional rearrangements may vary the shape, the size, the molecular weigh and, generally, the physic-chemical characteristics of proteins, which can be evidenced by poliacrilammide gel electrophoresis (PAGE). The isozymes are enzymatic forms which catalyze the same chemical reaction but differ in the physic-chemical characteristics of polypeptide chains. Also allelic variations and gene duplication and rearrangement contribute to isozymes polymorphism. The electrophoretical patterns of the isozymes of superoxide dismutase (SOD) have been proved as a powerful tool for analyzing the genetic variability of important nematode genera, such as Xiphinema, Longidorus, Globodera, Heterodera and Meloidogyne. Isoelectrofocusing of SOD isoforms was carried out on the extracts of 117 nematode populations belonging to the so-called Xiphinema americanum-group. The high degree of SOD polymorphism of this nematode collection allowed arranging, by a cluster analysis, the populations into 7 different homogeneous groups, characterized by specific combinations of SOD markers. The same analysis has been done with different populations of Globodera spp. by using cyst extracts: standards of the different pathotypes of G. rostochiensis and G. pallida cluster into different groups according to a data matrix built on SOD band polymorphism. Much slighter polymorphism has been evidenced between (a)-virulent populations of M. incognita.

Isozyme phenotypes of plant-parasitic nematodes as markers of genetic variability.

Molinari S
2006

Abstract

One of the methods suitable for investigation of the genetic variability of plant-parasitic nematodes is the analysis of protein and, in particular, of enzyme polymorphism. Changes of gene sequences lead to the replacement of amino acids in proteins with a rearrangement of their size and net charge. Proteins can be separated according to their net charge by an electrophoretical technique called isoelectrofocusing in which a determined pH gradient is established on separation gels. Additional rearrangements may vary the shape, the size, the molecular weigh and, generally, the physic-chemical characteristics of proteins, which can be evidenced by poliacrilammide gel electrophoresis (PAGE). The isozymes are enzymatic forms which catalyze the same chemical reaction but differ in the physic-chemical characteristics of polypeptide chains. Also allelic variations and gene duplication and rearrangement contribute to isozymes polymorphism. The electrophoretical patterns of the isozymes of superoxide dismutase (SOD) have been proved as a powerful tool for analyzing the genetic variability of important nematode genera, such as Xiphinema, Longidorus, Globodera, Heterodera and Meloidogyne. Isoelectrofocusing of SOD isoforms was carried out on the extracts of 117 nematode populations belonging to the so-called Xiphinema americanum-group. The high degree of SOD polymorphism of this nematode collection allowed arranging, by a cluster analysis, the populations into 7 different homogeneous groups, characterized by specific combinations of SOD markers. The same analysis has been done with different populations of Globodera spp. by using cyst extracts: standards of the different pathotypes of G. rostochiensis and G. pallida cluster into different groups according to a data matrix built on SOD band polymorphism. Much slighter polymorphism has been evidenced between (a)-virulent populations of M. incognita.
2006
PROTEZIONE DELLE PIANTE
Isozyme phenotypes
plant-parasitic nematodes
markers
genetic variability
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/85043
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