Haustorium invasion into host tissues

Abstract

The invasive phase of haustorium development starts when the young haustorium adheres to host roots by means of specialized attachment devices employing adhesive substances. A group of intrusive cells then enzymatically and mechanically penetrate host tissues. Enzymatic activity by the intrusive cells opens gaps between the host cells, while the elongation, multiplication and enlargement of the intrusive cells produce mechanical forces that push their way towards the host conductive system. Eventually some parasite cells contact host conductive cells, leading to the direct host-parasite vascular continuum. This chapter describes the various steps of penetration and discusses the question whether there is any parasite-host coordination during invasion.