Résumé
A DNA-A component of an Egyptian begomovirus was cloned from an isolate inducing enations on hollyhock (Althea rosea). Cytologic observations showed that the enations resulted from an intense multiplication of the phloem cells associated with the uncontrolled development of a pallisadic parenchym instead of a spongy parenchyma. The virus DNA exhibited a genetic organisation similar to other old-world begomoviruses like the tomato yellow leaf curl virus from Israel, but was significantly distinct (identity < 68916) to any other member of the family to be considered as a new viral species named Althea rosea enation virus (AREV). AREV induced enations and a leaf-curl on agro-inoculated Nicotiana benthamiana, but could not re-establish an infection on other host plants, neither A. rosea, nor cotton. The so-called 'cotton leaf curl' disease is thus induced by different viruses, including at least the cluster of cotton leaf curl viruses from Pakistan and AREV from Egypt. (Résumé d'auteur)