Molecular diagnostics to assess the progression of Phoma tracheiphila in Citrus aurantium seedlings and analysis of genetic diversity of isolates recovered from different citrus species in Tunisia.

  title={Molecular diagnostics to assess the progression of Phoma tracheiphila in Citrus aurantium seedlings and analysis of genetic diversity of isolates recovered from different citrus species in Tunisia.},
  author={Leila Kalai and Monia Mnari-Hattab and Hajlaoui},
  journal={Journal of Plant Pathology},
SUMMARY This study was focused on the genetic diversity of a collection of Phoma tracheiphila isolates recovered from different orchards and host species in Tunisia. Knowledge of the sequences permitted molecular assessment of the pathogen’s downward progression from the point of inoculation on citrus leaves. Analysis of 58 isolates of P. tracheiphila including four Italian isolates assessed by ITS-RFLP molecular markers revealed that Tunisian isolates of P. tracheiphila are homogenous and… 

Figures and Tables from this paper

Protective effect of Bacillus amyloliquefaciens against infections of Citrus aurantium seedlings by Phoma tracheiphila

Data suggest that lipopeptides produced by the bacterium interact with the cytoplasmic membrane of the fungus causing pore formation, and TEB1 appears a potential candidate for the biological control of citrus mal secco disease.

Identification of Field Tolerance and Resistance to Mal Secco Disease in a Citrus Germplasm Collection in Sicily

A phenotypic survey on a lemon and lemon-like open-field germplasm planted at CREA, Italy, in an area with high pathogen pressure revealed sources of tolerance in lemon and citron hybrids and indicated that the DNA from twigs is the most appropriate for use in performing reliable phenotyping of mal secco susceptibility in adult plants.

Major and Emerging Fungal Diseases of Citrus in the Mediterranean Region

The aim is to provide an update of both the taxonomy of the causal agents and their ecology based on a molecular approach, as a preliminary step towards developing or upgrading integrated and sustainable disease management strategies.

In vitro Antifungal Activities of Essential Oils of Three Lamiaceae Plant Species against Plenodomus tracheiphilus (syn. Phoma tracheiphila)

Leila Kalai-Grami*, LR / Biotechnologie Appliquée à l’Agriculture, Institut National de la Recherche Agronomique de Tunisie, Université de Carthage, Rue Hedi Karray, 1004 El Menzah 1, Tunis, Tunisia,


The present paper reviews the different aspects of citrus mal secco as studied worldwide over almost a century of research, from the first appeareance of the disease in Italy to date.



Molecular characterization of Phoma tracheiphila, causal agent of Mal secco disease of citrus, in Israel

This study developed a PCR-based method for the identification of P. tracheiphila from plant tissues including fruit and found no significant differences between different isolates from different citrus species from different parts of Israel.

Characterisation of Phoma tracheiphila by RAPD-PCR, microsatellite-primed PCR and ITS rDNA sequencing and development of specific primers for in planta PCR detection

A neighbor-joining analysis of ITS sequences of P. tracheiphila in comparison with those of other Phoma species, as well as with alignable sequences from anamorphic and teleomorphic taxa retrieved in BLAST searches, revealed a close relationship between P.tracheiphILA and Leptosphaeria congesta.

Identification and Detection of Phoma tracheiphila, Causal Agent of Citrus Mal Secco Disease, by Real-Time Polymerase Chain Reaction.

Real-time PCR was about 10- to 20-fold more sensitive than conventional PCR, and preliminary results indicate that the former technique achieves quantitative monitoring of the fungus in tissues.

Impairment of leaf hydraulics in young plants of Citrus aurantium (sour orange) infected by Phoma tracheiphila.

The close Kleaf-FVD relationship revealed that vein impairment caused drop of Kleaf and, consequently, of gL at chlorotic areas and that vein embolism due to the Phoma amplifies the native dominant hydraulic resistance of leaf veins, and leads ultimately to early shedding of infected leaves.

Induced tolerance to mal secco disease in Etrog citron and Rangpur lime by infection with the citrus exocortis viroid.

This is believed to be the first report of systemic resistance induced in a woody plant by prior inoculation with a viroid, regardless of prior infection by CEVd.

Characterization of a 60 kDa phytotoxic glycoprotein produced byPhoma tracheiphilaand its relation to malseccin

Results from carbohydrate analysis, following NaOH and N-glycosidase F treatments, indicated that Pt60 is a highly glycosylated protein (55% carbohydrate).

Occurrence of 'mal nero' disease on mandarin and orange trees in Tunisia

This is the first report of ‘mal nero’ disease occurring naturally on mandarin and orange trees and the first time this disease has been reported in Tunisia.

Development of real-time PCR systems based on SYBR® Green I and TaqMan® technologies for specific quantitative detection of Phoma tracheiphila in infected Citrus

Comparisons with classic methods suggest that real-time PCR, based on both chemistries, has a great potential for early diagnosis of ‘mal secco’ disease and for quantitative estimation of fungal growth within host tissue.

Effect of mal secco toxin on lemon leaf cells

The ultrastructural changes in toxin-treated leaves of Rough lemon resembled closely those infected by the pathogen, being characterized by separation of the plasmalemma from the cell wall, vesiculation of plas malemma, disruption of the chloroplast membrane, disorganization of thylakoids, and increase in size and number of osmiophilic droplets in the chloroplasts.

Mal Secco Disease Caused by Phoma tracheiphila: A Potential Threat to Lemon Production Worldwide.

Mal secco of citrus is a highly destructive vascular disease of lemon, presently confined to the Mediterranean basin, which has a relevant economic impact on the lemon industry in this geographic region.