The infection process of Mauginiella scaettae as the causal agent of date palm (Phoenix dactylifera L.) inflorescence rot.

Plant pathogenic fungi have developed diverse mechanisms to penetrating their hosts, often based on the development of modified hyphae. Initial events involve adhesion to the plant cuticle but then can either involve the production of hydrolytic enzymes to digest the host or the epidermal penetration following the formation of an aspersorium and a feeding structure known as a haustorium or directed hyphal growth of the germ tube to a natural plant openings (stomata) which a penetrated and haustoria then typically form within the sub-stomatal chamber. The fungus Mauginiella scaettae is the causal agent of inflorescence rot of date palm, an economically devastating disease in Algeria, whose infection process has been poorly characterised. We here present a cytological description of how M. scaettae infects its host based on light and scanning electronic microscopy up to 2 weeks following initial pathogenic challenge. It was notes that appressoria were formed at the site of infection which may develop high turgor pressure to support the penetration process. It was also noted that there was some evidence of stomatal targeting and penetration by M. scaettae hyphae. This preliminary work will facilitate further studies which aim to increase resistance through to derivation of resistant date germplasm or the use of biocontrol agents.

Key words: Date palm, inflorescence rot, Mauginiella scaettae, infection, penetration.