Strategies of attack and defence in woody plant–Phytophthora interactions

Abstract

Summary This review comprises both well‐known and recently described Phytophthora species and concentrates on Phytophthora–woody plant interactions. First, comprehensive data on infection strategies are presented which were the basis for three models that explain invasion and spread of Phytophthora pathogens in different woody host plants. The first model describes infection of roots, the second concentrates on invasion of the trunk, and the last one summarizes infection and invasion of host plants via leaves. On the basis of morphological, physiological, biochemical and molecular data, scenarios are suggested which explain the sequences of reactions that occur in susceptible and tolerant plants following infections of roots or of stem bark. Particular emphasis is paid to the significance of Phytophthora elicitins for such host–pathogen interactions. The overall goal is to shed light on the sequences of pathogenesis to better understand how Phytophthora pathogens harm their host plants.

Short communication: Effect of mycoviruses on growth, spore germination and pathogenicity of the fungus Fusarium circinatum

“…data). Further studies should therefore be carried out at different temperatures and with other techniques, such as fluorescence (Oßwald et al, 2014) and molecular methods (Bodles et al, 2006), to determine the damage caused beyond the visible symptoms. …”

Induction of defence responses by cinnamomins against Phytophthora cinnamomi in Quercus suber and Quercus ilex subs. rotundifolia

“…For example, most Phytophthora and a few Pythium species specifically secrete large amounts of elicitins, a group of unique highly conserved proteins whose molecular roles have been investigated and constitute a matter of debate (reviewed by Ponchet et al 1999;Oßwald et al 2014). Elicitins are able to facilitate infection (virulence factors), appear to be required for the colonization process, and are determinants for the aggressiveness of the pathogen.…”

“…Elicitins are able to facilitate infection (virulence factors), appear to be required for the colonization process, and are determinants for the aggressiveness of the pathogen. For instance, it was recently reported for the Q. suber-P. cinnamomi pathosystem using a β-cinnamomin (β-CIN) knock-down P. cinnamomi strain (Horta et al 2010) and shown for the role of citricolin from P. plurivora in the infection of beech roots (Oßwald et al 2014), and also suggested by the positive correlation of virulence with ram-a2 expression in P. ramorum (Manter et al 2010). Elicitins were shown to induce defence responses in plants (avirulence factors or elicitors) (Bonnet et al 1996).…”

<i>Phytophthora nicotianae</i>: ação de meios de cultura e da qualidade da luz no crescimento e esporulação e aspectos fisiológicos e bioquímicos da interação com porta-enxertos cítricos

“…Essas duas isoflavonas são as mais investigadas para a especificidade na atração de zoósporos e são encontradas em concentrações elevadas nas sementes. Quando do processo de germinação do hospedeiro, a liberação dessas duas isoflavonas ocorre pelas raízes, na região da rizosfera (OßWALD et al, 2014;ZHU et al, 2005 A ação da corrente elétrica na motilidade de zoósporos também é outro tipo de taxia estudado, pois muitos zoósporos são atraídos eletrostaticamente para as diversas superfícies de potenciais plantas hospedeiras (TYLER, 2002). Os gradientes elétricos gerados pelas raízes das plantas na rizosfera são condições que influenciam na direção dos zoósporos, ora levando-os para perto ou para longe da superfície das raízes (MORRIS; REID; GOW, 1992).…”