Detection and partial characterization of a putative closterovirus affecting Ficus carica: molecular, ultrastructural and physiological aspects of infected leaves

Abstract

Fig mosaic disease (FMD) was systemically transmitted to susceptible fig plants by grafting and led to development of symptoms including a wide array of discoloration, green blisters, mottling, crinkling and deformation of leaves and fruits. A sensitive assay for the detection of FMV using specific enzyme-linked immune sorbent assay and reverse transcription-polymerase chain reaction was developed. A double-stranded RNA ca. 19 kbp in size was obtained from the fig tissue extract and used as a template. A cDNA fragment (350 bp) of phosphate motifs 1 and 2 of the heat shock-protein 70 homologue of the family Closteroviridae was amplified using a specific primer set. Virions were flexuous filaments up to 1,800 nm in length and *21 nm in diameter. Viral infection formed new polypeptides in leaves that reflect pathogen-related proteins. Total photosynthetic pigment contents of virus-infected leaves decreased by 33.06%, with a raise in chl a/b ratio that was mainly caused by a decline in chl b content. Chloroplasts of virus-infected leaves lost their envelopes, and the internal structures of grana and stroma thylakoids were deformed and turned to spherical shapes. No virus inclusion bodies were detected in chloroplasts or other mesophyll cell organelles. Starch grains of chloroplasts were absent in the virus-infected leaves. Viral infection caused a decline in catalase and induction in peroxidase activities in leaves. Levels of thiobarbituric acid reactants in viral-infected leaves increased by 15%, while the content of total phenolics increased by 29%, in respect to healthy ones. The present results indicate a possible presence of Fig leaf mottle-associated virus-1 (FLMaV-1) in fig trees and provide an overview of the negative effects on fig leaves in response to FLMaV-1 infection from morphological, physiological and subcellular perspectives.

Detection and Phylogenetic Analysis of Viruses Linked with Fig Mosaic Disease in Seventeen Fig Cultivars in Palestine

“…However, assuming a large number of cultivars existing, this may not be accurate for others. There is also an apparent possibility that fig infection with FBV-1 modifies the internal physiology of the plant, as has been demonstrated with FLMaV-1 (Fayez and Mahmoud, 2011). Badnaviruses are also recognized to play a significant part in viral disease combinations (Jones et al, 2002), and that their participation in mixed infections causes severe symptoms in crops propagated by rooted cuttings (Tzanetakis et al, 2007;Wang and Valkonen, 2008).…”

Fusilade herbicide causes alterations in chloroplast ultrastructure, pigment content and physiological activities of peanut leaves

“…The post-emergence herbicides used in peanuts for weed control are paraquat, 2,4dichlorophenoxybutanoic acid, acifluorfen, and graminicides such as clethodim, fusilade (fluazifop-p-butyl), and sethoxydim (Wilcut et al 1994, Gnanamurthy and Balasubramaniyan 1998, Horbowicz et al 2013. However, injuries of plant cell organelles and alteration in the physiological activities have resulted from the application of herbicides (Fayez and Kristen 1996, Fayez and Hassanein 2000, Radwan 2012.…”

“…Oxidative stress induced by abiotic and biotic factors through ROS may disrupt the membrane integrity as a consequence of lipid peroxidation (Feierabend and Winkelhüsener 1982, Lambert and Bondy 1989, Banaś et al 2000, Fayez and Mahmoud 2011, Lukatkin et al 2013, Fayez and Bazaid 2014. Malondialdehyde (MDA) content is widely used to measure the extent of lipid peroxidation and as an indicator of oxidative stress and membrane damage (Ohkawa et al 1979).…”

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

“…It has been reported that high temperatures affect the starch metabolism producing its accumulation in wheat and rice cultivars (Yamakawa & Hakata, 2010;Zhao et al, 2008). Also, some viruses such as fig mosaic virus (FMV), tomato spotted wilt virus (TSWV) or zucchini yellow mosaic virus (ZYMV) induce the accumulation of starch in chloroplasts (Fayez & Mahmoud, 2011;Zechmann et al, 2021;Zhan et al, 2021). Large starch accumulation in mesophyll cells of N. benthamiana and broad plants infected with pBBWV-1 wt but not in those infected with pBBWV1-G492C suggest a role of VP37.…”