Home • Phoma tracheiphila IPT5 v1.0
Phoma tracheiphila on PDA
Phoma tracheiphila on PDA. An achromatic colony (producing no pink pigment) above and a chromatic colony (producing pink pigment) below. Both are pathogenic.
Photo by David Ezra.

Phoma tracheiphila (Petri) Kant. & Gik. (syn. Deuterophoma tracheiphila Petri) is a fungal pathogen of Citrus, Poncirus, Severinia and Fortunella spp. This pathogen is the causal agent of a disease known as Mal secco (“mal fulminante” and "mal nero” are other forms of the disease). Mal secco of citrus is a highly destructive vascular disease of citrus, mainly lemons, presently confined to the Mediterranean basin, which has a relevant economic impact on the lemon industry in this geographic region. The disease is not known to occur in the citrus-growing countries of the Americas or Oceania, even though there is no obvious climatic or cultural factor limiting the establishment of Mal secco disease in other areas. P. tracheiphila  is considered as a quarantine pathogens in almost all citrus-growing countries. Typical symptoms of the disease include veinal chlorosis, leaf wilt; red coloration of the xylem and dieback of twigs and branches; in many cases dieback is sectorial. The pathogen proceeds slowly downward from the infected leafs or young shoots to the branches and main limbs; when the trunk and roots become infected, the tree dies. When the fungus infects the base of a trunk or the roots, a phenomenon known as – mal fulminante accures. In these cases, the tree usually dies quickly. P. tracheiphila  location in the plants xylem, making it impossible to control by chemical control. Resistance cultivars of lemons are currently not available. Identifying the factors and genes involve in the fungus virulence on it host is central for the understanding of pathogenicity process and pathogen host interactions. The P.tracheiphila genome sequence will reveal fungal mechanisms of surviving in the host xylem and virulence toward its host, and hopefully will also help us to find new ways to cope with it in orchard.