Subcellular effects of broad bean wilt virus 1 infection in Nicotiana benthamiana and broad bean plants

Abstract

Broad bean wilt virus 1 (BBWV-1) from the genus Fabavirus (family Secoviridae) infects many important crops worldwide. We have studied the subcellular alterations in leaf tissues of Nicotiana benthamiana and broad bean (Vicia faba) plants infected by BBWV-1 using transmission electron microscopy (TEM). In addition, we have studied the effect at the subcellular level of the BBWV-1 VP37 protein, which is a pathogenicity and host specificity determinant. For this, we agroinfiltrated N, benthamiana, and broad bean plants with two BBWV-1 infective clones, the wild type pBBWV1-wt and pBBWV1-G492C defective for VP37. Mesophyll cells infected with BBWV1-wt showed many subcellular alterations such as starch accumulation and plastoglobuli in chloroplasts, cytoplasmic vesiculation, plasmalemmasomes, vacuolar inclusion bodies, and presence of virus-like particles (VLPs) scattered in the cytoplasm in both N. benthamiana and broad bean. As differential effects, aggregated VLPs in vacuolar inclusion bodies and mitochondrial proliferation were observed in N. benthamiana but not in broad bean. TEM observation of pBBWV1-G492C infected tissues suggested that VP37 could be involved in the starch accumulation in Revised version of the manuscriptClick here to access/download;Manuscript;Medina et al., BBWV-1 TEM (VRew Def).docx Click here to view linked References both N. benthamiana and broad bean, and with the presence of aggregated VLPs in vacuolar inclusion bodies, plasmalemmasomes, and mitochondrial proliferation in N. benthamiana. Thus, subcellular alterations induced by BBWV-1 depended on the host species and the effect of VP37 expression was higher in N. benthamiana than in broad bean.

Proteomic insights into the effect of Broad bean wilt virus-1 infection in Nicotiana benthamiana plants

“…All plants showed some necrotic spots in the in ltrated leaves due to the mechanical injuries produced during the in ltration process. These results are identical to those previously reported that described severe symptoms in N. benthamiana plants agroin ltrated with pBBWV1-Wt or mechanically infected with BBWV-1 and slight symptoms in equivalent plants agroin ltrated with pBBWV1-G492C (Carpino et al, 2020a;Medina et al, 2022).…”

“…For these two host proteins, only the underexpression of the last one was associated with the viral VP37 protein expression and plasmalemmasomes formation. Other membranous alterations reported previously in N. benthamiana plants agroin ltrated with pBBWV1-Wt and pBBWV1-G4922C were the increase of cytoplasmic vesicles (Medina et al, 2022). In this case, cytoplasmic vesiculation did not depend on viral VP37 protein, and could be consequence of overexpression of GDPDL6 in both groups of plants.…”

“…Predicted functions and localizations of the proteins showing differential expression revealed an alteration in the principal metabolic and physiological processes of N. benthamiana plants infected with BBWV-1. These proteins were localized in different cellular organelles but mainly in chloroplast, which is affected by the virus infection inducing the accumulation of starch and plastoglobuli (Medina et al, 2022).…”

“…Several tobacco species such as Nicotiana benthamiana and N. tabacum are highly susceptible to virus infections and they have been widely used for different studies. Recently, the effect of BBWV-1 infection in N. benthamiana was studied by Transmission Electron Microscopy (TEM), reporting many subcellular changes in chloroplasts, plasmatic membrane, and mitochondria, and the presence of virus-like particles aggregates in inclusion bodies into the vacuoles (Medina et al, 2022). Furthermore, some of these ultrastructural alterations could be associated with the expression of BBWV-1 VP37 protein, which is a host speci city and pathogenicity determinant that was previously identi ed by using 35S-driven viral full-length cDNA infectious clone (pBBWV1-G4922C) knocking out the viral VP37 protein (Carpino et al, 2020a).…”

“…producing important subcellular alterations(Carpino et al, 2020a;Carpino et al, 2020b;Medina et al, 2022) Proteomic analysis employing different platforms has been successfully used for the study of plant-virus interactions for several viruses(Jain et al, 2021;Souza et al, 2019). However, the detection of host proteins showing differential expression depended on many factors such as the virus-plant model studied, the proteomic technique employed (including restriction levels implemented by statistical analysis) and the infection period.…”