Modifications in Tissue and Cell Ultrastructure as Elements of Immunity-Like Reaction in Chenopodium quinoa against Prune Dwarf Virus (PDV)

Abstract

Prune dwarf virus (PDV) is a plant RNA viral pathogen in many orchard trees worldwide. Our knowledge about resistance genes or resistant reactions of plant hosts to PDV is scant. To fill in part of this gap, an aim of this study was to investigate reactions to PDV infection in a model host, Chenopodium quinoa. Our investigations concentrated on morphological and ultrastructural changes after inoculation with PDV strain 0599. It turned out that PDV infection can cause deformations in host cells but also induce changes in the organelles, such as chloroplasts in inoculated leaves. Moreover, we also demonstrated specific reactions/changes, which could be associated with both types of vascular tissue capable of effectively blocking the systemic spread of PDV to upper leaves. Furthermore, the relative amount of virus, P1 protein deposition, and movement protein (MP) gene expression consequently decreased in PDV-inoculated leaves.

Complexity of Brassica Oleracea-Alternaria Brassicicola Susceptible Interaction Reveals Down-regulation of Photosynthesis at Ultrastructural, Transcriptional and Physiological Levels

“…The appearance of necrotic spots indicated successful invasion and colonization of the host tissues by A. brassicicola, although host cells were differentially affected within the inoculation site depending on the distance from the invading hyphae, as evidenced by the gradual degradation of organelles. Similar individual changes in the ultrastructure of infected plant host cells, such as cell lysis, disintegration of the nuclei and chloroplasts or the presence of osmiophilic granules have been observed in other pathosystems during infection with viruses, bacteria and fungi [46][47][48][49]. In the case of infected B. oleracea mesophyll cells, these changes could be a result of the action of toxins and secondary metabolites secreted by A. brassicicola [16] and general reprogramming of the host transcriptome and metabolome in response to the infection [50,51].…”

Complexity of Brassica oleracea–Alternaria brassicicola Susceptible Interaction Reveals Downregulation of Photosynthesis at Ultrastructural, Transcriptional, and Physiological Levels

“…The appearance of necrotic spots indicated successful invasion and colonization of the host tissues by A. brassicicola , although host cells were differentially affected within the inoculation site depending on the distance from the invading hyphae, as evidenced by the gradual degradation of organelles. Similar individual changes in the ultrastructure of infected plant host cells, such as cell lysis, disintegration of the nuclei and chloroplasts, or the presence of osmiophilic granules have been observed in other pathosystems during infection with viruses, bacteria, and fungi [ 55 , 56 , 57 , 58 ]. It has to be mentioned that rounded chloroplasts were also observed in B. juncea cells in response to A. brassicicola infection, although the cup-shaped thylakoid system was not found [ 9 ].…”

Respiratory Burst Oxidase Homologs RBOHD and RBOHF as Key Modulating Components of Response in Turnip Mosaic Virus—Arabidopsis thaliana (L.) Heyhn System

“…Fifty plants of Col-0 and fifty plants of each type of mutant were mechanically inoculated as described by Tomilson (1970) and Walsh and Jenner (2002) [ 69 , 70 ] by using the TuMV inoculum (isolate PV-0104 from Leibniz Institute, Braunschweig, Germany) in phosphate buffer [ 71 ]. Leaves of mock- and TuMV-inoculated plants were assessed for the presence of virus by using DAS-ELISA, as published before by Kozieł et al [ 72 ], with the primary antibodies against the TuMV (Bioreba, Reinach, Switzerland), followed by purified antirabbit antibodies conjugated with alkaline phosphatase (Bioreba, Switzerland) [ 73 ]. Each repeat was performed in a new ELISA plate with samples.…”

“…The readings of OD 405nm values were acquired after 60 min in duplicate, 3 and 7 days after inoculation. The mean OD 405nm values were statistically assessed with a one-factor analysis of variance (ANOVA), as described in Kozieł et al [ 72 ] with the Statistica software (version 13.0; StatSoft and TIBCO Software Inc., Palo Alto, CA, USA). For a more precise assessment, the corrected mean OD 405nm values were computed as presented in [ 72 ] and used to compare the relative level of virus presence/concentration in plants.…”

“…The mean OD 405nm values were statistically assessed with a one-factor analysis of variance (ANOVA), as described in Kozieł et al [ 72 ] with the Statistica software (version 13.0; StatSoft and TIBCO Software Inc., Palo Alto, CA, USA). For a more precise assessment, the corrected mean OD 405nm values were computed as presented in [ 72 ] and used to compare the relative level of virus presence/concentration in plants. The cut-off point was also calculated by using a formula suggested by Bioreba (Switzerland) [ 74 ]: Cut-off = mean value (of all negative-healthy plants from 3 and 7 dpi) × 3 …”