Morphogenesis and Mechanisms of Penetration by Plant Pathogenic Fungi

Abstract

Infection structures of phytopathogenic fungi are modified hyphae specialized for the invasion of plant tissues. Initial events are adhesion to the cuticle and directed growth of the germ tube on the plant surface. At the site of penetration, appressoria are often formed that may have melanized walls and develop high turgor pressure to support the penetration process. The penetration hypha accumulates components of the cytoskeleton in the tip and secretes a variety of cell wall-degrading enzymes in a highly regulated fashion in order to penetrate the cuticle and the plant cell wall. This article reviews recent papers on the cytology, physiology, and molecular biology of the penetration process.

The multifaceted role of ABA in disease resistance

“…ABA signaling in pre-invasive penetration resistance Pathogens need to penetrate plant tissue to infect a host plant successfully. Some fungi overcome the first cell layer by applying mechanical force onto the epidermal cell wall or by secreting cuticle-and cell-wall-degrading enzymes [6,7]. Other pathogens instead use pre-existing openings, such as stomata or wounds ( Figure 1, Phase I).…”

“…. Some fungal and oomycete pathogens can penetrate the cell wall directly, whereas others enter the tissue through natural openings, such as stomata or wounds [6,7]. Bacteria depend largely on these openings, because most are unable to penetrate directly through the cuticle and cell wall.…”

“…Effects of the ABA signaling web on early and late defense barriers. ABA boosts pre-invasive penetration resistance (Phase I) by stimulating PAMP-induced stomatal closure [6]. A pathway that involves the mitogen-activated protein kinase kinase 1 (MKK1)-mitogen-activated protein kinase 6 (MPK6) signaling cascade [55] and the protein kinase OST1 (OPEN STOMATA 1) [56] regulates ABA-induced ROS production, which consecutively regulates stomatal closure and other downstream signaling events.…”

A nuclear contortionist: the mitotic migration ofMagnaporthe oryzaenuclei during plant infection

“…For example, Colletotrichum spp. form an appressorium-derived penetration peg to initially enter their host cells (Mendgen et al 1996; Nesher et al 2008; De Silva et al 2017). Fusarium graminearum forms intracellular hyphae that exhibit apparent constriction during cell-to-cell movement (Jansen et al 2005).…”

Mining Effector Proteins in Phytopathogenic Fungi

“…By manually comparing, there were putative ascribed functions of 62 RxLx motif-containing secretory proteins of M. grisea (Table 1) (Tudzynski and Sharon, 2003;Mendgen et al, 1996).…”