Vol. 51 No. 1 (2012)
Research Papers

An endopolygalacturonase gene of Diaporthe helianthi

Valentina CATALANO
Dip. Coltivazione e Difesa Specie Legnose “G. Scaramuzzi”, Sez. Patologia Vegetale, Università di Pisa, Italy
Djaouida REKAB
Dip. Biologia e Protezione delle Piante, Sez. Patologia Vegetale, Università di Udine, Italy
Giuseppe FIRRAO
Dip. Biologia e Protezione delle Piante, Sez. Patologia Vegetale, Università di Udine, Italy
Giovanni VANNACCI
Dip. Coltivazione e Difesa Specie Legnose “G. Scaramuzzi”, Sez. Patologia Vegetale, Università di Pisa, Italy
Mariarosaria VERGARA
Scuola Normale Superiore di Pisa, Piazza dei Cavalieri 7, Pisa, Italy and Dip. Coltivazione e Difesa Specie Legnose “G. Scaramuzzi”, Sez. Patologia Vegetale, Università di Pisa, Italy

Published 2012-03-26

Keywords

  • cell wall degrading enzymes,
  • molecular diversity,
  • Phomopsis helianthi

How to Cite

[1]
V. CATALANO, D. REKAB, G. FIRRAO, G. VANNACCI, and M. VERGARA, “An endopolygalacturonase gene of Diaporthe helianthi”, Phytopathol. Mediterr., vol. 51, no. 1, pp. 23–36, Mar. 2012.

Abstract

In an attempt to define virulence determinants of Diaporthe helianthi, the causative agent of sunflower stem canker, the gene named Dhpg, coding for an endopolygalacturonase, was investigated in the highly virulent strain 8/96 isolated from a diseased plant in France. The 1130 bp coding sequence, in addition to 1473 bp from the upstream region, were cloned, sequenced and analyzed. Dhpg was most closely related to polygalacturonase genes from phytopathogenic fungi, such as Ophiostoma ulmi, O. novo-ulmi, and Gibberella zeae. A Southern blot RFLP analysis proved that Dhpg was represented in single-copy in the genome of the isolate 8/96. Analyses carried out both in vitro on liquid cultures and in vivo on host infected tissues provided evidence of the constitutive expression of the Dhpg transcript under all tested conditions. Moreover, an European collection of D. helianthi isolates was screened for the presence of Dhpg homologues by PCR, revealing the same single band in all French and Yugoslavian isolates, while one Romanian and all Italian isolates displayed a variable pattern. This genetic variability related to the different geographic origin of D. helianthi is consistent with data previously reported for different loci on the same set of isolates. This is the first report of a polygalacturonase gene in D. helianthi.

Downloads

Download data is not yet available.

Metrics

Metrics Loading ...