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Related to appressorium: haustoria, tyloses


n. pl. ap·pres·so·ri·a (-sôr′ē-ə)
The flattened tip of a hypha in various species of parasitic fungi, from which a filament emerges that penetrates the host's tissues.

[New Latin appressōrium, from Latin appressus, past participle of apprimere, to press down; see appressed.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


n, pl -ria (-rɪə)
(Botany) botany a flattened hypha of a parasitic fungus that penetrates the host tissues
[from New Latin, from Latin appressus; see appressed]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
References in periodicals archive ?
In series, the pathogen sporangium or zoospore has to be formed followed by cyst formation, then germination of the cyst/spore to form appressorium which, enhances penetration unto host and infection vesicle, then intercellular hyphal growth and haustorium formation and initiation of sporulation (Huitema et al., 2004; Nowicki et al., 2013).
It begins from the attachment of a three-celled conidium to the rice leaf, followed by the germination of the conidium and the differentiation of the germ tube into a dome-shaped cell called appressorium. The appressorium matures and generates turgor by accumulating high concentrations of compatible solutes, which can directly penetrate the host cuticle, resulting in a disease lesion.
Hyphae also can grow from one vessel member to another through perforated end walls as well as directly through secondary wall material by using an appressorium. It appears as if the torus-bearing pit membranes' only function is associated with the inhibition of passage of air embolisms and not with inhibiting fungal movement.
The proteins identified as exclusive to the conidia were involved in protective processes, appressorium formation, and the degradation of the host cuticle and exclusive proteins to mycelia were involved in biosynthetic and energy-generating metabolic processes, such as UTPglucose-1-phosphate uridylyltransferase and heatshock protein 70.
The fungal entry into roots was characterized by the formation of an appressorium originating from the extraradical hyphae on the root surface (Figure 1(a)).
[22] constructed a mutant library for Magnaporthe oryzae using ATMT and several infectious and pathogenic mutants were identified to be involved in appressorium formation, melanin synthesis, and cell wall degrading enzymes.
The disease cycle begins with conidia contacting and adhering to the integument of the host (Figure 1), followed by germination, appressorium production (Figure 2a) or without appressorium formation (Figure 2b), penetration (Figure 3a,b), development in the hemocoel with the dimorphic (yeast-like forms) stage represented by the formation of short, thick and septated hyphal bodies, mostly with one or more septation (Figure 3a), to mycelial exteriorisation (Figure 4a,b) and as shown (Figure 6 a,b) on pupae mycelial exteriorisation and conidiogenesis on the carcass.