Mariya Stoyanova

• PhD
• Professor (Associate) at Agricultural Academy - Bulgaria

Erwinia amylovora is a devastating pathogen of plants of the family Rosaceae causing blight on the leaves, shoots, and flowers. Orchard trees suffer the most, however, other plants, like roses, strawberries, raspberries, and hawthorn, can also be affected. Due to the extreme use of chemicals for plant protection, alternatives like plant extracts ha...

Vegetables are very important invaluable resource for the nutrition of the world’s population. Biotic stress and viruses, in particular, are one of the major environmental stressors that damage vegetable plants and the quality and quantity of agricultural yield. More than 200 virus species from different virus genera have been identified to infect...

Potato is the world’s third most widespread food crop, following wheat and rice. Tubers play an important role in the spread of virus diseases in different regions in Bulgaria for seed production. The most important viruses in potatoes in Bulgaria include Potato virus Y (PVY), Potato leaf roll virus (PLRV), Potato virus S (PVS), and Potato virus M...

https://doi.org/10.1016/B978-0-323-95339-9.00007-7

Potato virus Y (PVY) is one of the most dangerous pathogens that cause serious damage to crop production. Fighting plant viral infections is crucial to limit these damages and save millions of dollars for farmers. Gene suppression of selected virus genes is one of the modern, innovative and effective approaches to block viral replication and infect...

Coxsackieviruses are distributed worldwide and can cause serious diseases threatening human health and even human life. Genetic silencing is considered a new opportunity to treat viral infections. In this study, we produced in vitro dsRNAs and siRNAs specific for two sequences of different length from the VP1 genetic regions of CVB3, and introduced...

Potato virus Y (PVY) is the reason for significant losses in the potato crop yearly. The recent technologies in molecular biology have given insights on possibilities for control of viral infections at epigenetic level. In the present study, we obtained a DNA template complementary to a key sequence at the NIb genetic region of PVY. Potato leaves w...

Ornamental bulbous plants from family Liliaceae are an increasingly important floricultural crop all over the world. Virus diseases are of great economic importance in bulbous flowers because most of them are propagated vegetatively by tissue culture, scions, bulbs or other tissues. Once infected with a virus, the plants of the Liliaceae family rea...

Tomato is the most widely produced vegetable crop in the world. It is damaged by a number of fungal, bacterial, and viral pathogens which reduce fruit yields and quality. Viral infections are a major factor limiting tomato production. Due to the considerable economical losses, management of viral diseases is of a vital significance for tomato produ...

RNA gene silencing is a mechanism for gene regulation, which limits transcription level by suppression of transcription (transcriptional gene silencing, TGS) or by activation of a process of degradation of specific RNA sequence (post-transcriptional gene silencing, PTGS), known also as RNA interference (RNAi). RNA interference was observed for the...

Post-transcriptional gene silencing is an effective tool for viral replication control at the epigenetic level. In this study, we aimed to produce dsRNAs and siRNA pools targeting the genetic region for the viral protease 3C and the genetic region covering the sequences for VP1 and VP3 capsid proteins of the Coxsackievirus B3 cardiotropic Woodruff...

Since 2014, an unusual appearance of tomato seeds (Solanum lycopersicum) has been observed. The seeds were produced from local tomato genotypes from Bulgaria without visible symptoms of disease. The seeds exhibited small or large brown-grey spots on the surface that affected also the deeper layers. The most affected seeds lacked germinating ability...

Potyviruses are the largest group of plant virus pathogens, which are constantly expanding their territories of emergence, threatening their hosts worldwide. Potato virus Y(PVY) epidemics have a serious negative impact on agricultural productivity, resulting in significant losses to farmers. The need of efficient technique to control PVY is essenti...

Bacterial spot is an important disease of pepper in Bulgaria and Macedonia. For characterization of Xanthomonas species associated with bacterial spot, 161 strains were collected from various field pepper-growing regions. Among them, 131 strains were identified as Xanthomonas euvesicatoria and 30 as Xanthomonas vesicatoria using species-specific pr...

Tomato plants of all ages are susceptible to Clavibacter michiganensis subsp. michiganensis, Xan-thomonas sp. and Pseudomonas syringae pv. tomato. Control is based mainly on copper-containing chem-icalsand is often unsatisfactory. The object of this study was to test the effect of extracts from different, common for Bulgaria, medicinal and weed pla...

Summer snowflake is a valuable, endangered species, from which the Bulgarian drug Nivalin® is produced. The artificial infections were carried out in sterile conditions on in vitro bulbs from six natural populations of Bulgarian summer snowflake with 4 bacterial isolates from bulbs with symptoms of decay. The symptoms were traced on the 3rd, 6th an...

The use of appropriate DNA markers facilitates the selection in plant breeding. Molecular markers for potato can be derived from retrotransposons such as SINEs (Short Interspersed Nuclear Elements) which are widely dis- persed over all chromosomes and hence facilitate a sufficient genome coverage for genotyping. The ISAP method describes the PCR am...

Cucumber mosaic virus (CMV) and Potato virus Y (PVY) have been described among the top five important viruses infecting vegetable species worldwide. They cause severe damages in fruits and cultivated plants. There is currently no available effective pesticide to control these viral diseases. Higher plants contain a wide spectrum of secondary metabo...

Bacterial spot of pepper and tomato plants is one of the most important constraints limiting crops yield in Bulgaria and Macedonia. Therefore,early identification of the pathogen is necessary for the control and prevention of the disease. In order to explore the strength of 16S-23S ITS rDNA PCR-RFLP as an approach for identification and differentia...

This book focuses on the evolution of plant viruses, their molecular classification, epidemics and management, covering topics relating to evolutionary mechanisms, viral ecology and emergence, appropriate analysis methods, and the role of evolution in taxonomy. The currently emerging virus species are increasingly becoming a threat to our way of li...

Induction of systemic acquired resistance in pepper to X. vesicatoria pepper pathotype after treatment with X. vesicatoria tomato pathotype and Pseudomonas syringae pv. tomato ABSTRACT Bacterial spot caused by Xanthomonas vesicatoria is an economically important disease of pepper which is the reason for yearly losses in vegetable production. Contro...

Various essential oils have potential for use in alternative strategies for plant pathogen control. In this work twelve essential oils and several of their components were screened for antibacterial activity against the causative agents of bacterial spot of pepper – Xanthomonas vesicatoria and Xanthomonas euvesicatoria, using the agar diffusion met...

Bacterial spot caused by Xanthomonas euvesicatoria is an economically important disease of pepper which is the reason for yearly losses in vegetable production. The control of the pathogen is hard and is mainly relied on the extensive use of copper-based chemicals. In the present study we successfully induced systemic resistance in pepper plants of...

Chelidonium majus is an important medical plant used in traditional and folk medicine throughout the world. In the folk medicine of the Balkan countries it is widely used for its anticholera, antispasmodic, and sedative properties. C. majus extracts exhibit antiviral, antitumour, antimicrobial and anti-inflammatory effects. In our research we demon...

Chelidonium majus is an important medical plant used in traditional and folk medicine throughout the world but also a common weed in nature and around human habitats. C. majus extracts exhibit antiviral, antitumour, antimicrobial and anti-inflammatory effects. The present study is focused on the investigation of extracts from C. majus against Xanth...

Bacterial spot (BS) of pepper caused by the pathogens of genus Xanthomonas is an economically important disease affecting pepper plantations all over the world. During the last 20 years, the causative agents of BS have been subject to many reclassifications. According to the current data, BS is caused by four widely distributed species: Xanthomonas...

Plant viruses are a major threat to seed production and potato yield in Bulgaria. The main plant viruses infecting potatoes are Potato virus Y (PVY), Potato leaf roll virus (PLRV), Potato virus A (PVA), Potato virus X (PVX), Potato virus V (PVV), Tobacco rattle virus (TRV) and Tomato spotted wilt virus (TSWV), of which PVY and PLRV are of greater e...

Bacterial spot of pepper caused by Xanthomonas euvesicatoria is an economically important disease which causes yield losses yearly. Control is difficult and is based mainly on copper-based chemicals. However, recent studies showed that copper in concentrations that are most used in practice give contradictory results. The aim of this study was to t...

This study presents the first whole genome sequence of Onion yellow dwarf virus (OYDV isolate RR1) from onion (Allium cepa) in India along with phylogenetic and recombination studies. We examined the sequence variability, distribution of simple sequence repeats (SSRs), and recombination breakpoints of different OYDV geographical isolates. The P1 an...

Plant virus diseases are the second biggest group after the fungal diseases in agricultural production. Enormous economic loss in agriculture is caused by the virus diseases. The traditional prevention and control of the virus diseases are mainly agricultural control measures. Potato virus Y (PVY) is the type species of genus Potyvirus from family...

Bacterial speck of tomato caused by Pseudomonas syringae pv. tomato is an important disease in many tomato growing areas. The pathogen is known to comprise two races – R0 and R1. Sixty-seven pathogenic strains isolated in the period 2000 – 2013 from tomatoes with symptoms of bacterial speck in Bulgaria were the object of this study. The isolates we...

Papaya ringspot virus (PRSV) belongs to Potyviridae family, genus Potyvirus and mainly transmitted by aphids (genera Macrosiphum and Myzus). Infected plants show mottling, blister-like patches and distortion of leaves as well as causes ring spot disease in papaya (Carica papaya L.) fruits. The HC-Pro (helper component proteinase), CI (cylindrical i...

Potato viruses cause enormous economic loss in agriculture production. Potatoes can be infected by a number of different viruses that affect negatively the harvest and the tuber quality. Direct and effective drugs against plant virus diseases are still not available and control is only applied as agricultural measures and pesticides against virus v...

Sub-species diversity of pepper populations of Xanthomonas euvesicatoria in Bulgaria and Macedonia in 2012 was the object of this study. Species determination of 44 strains was performed by molecular methods using two pairs of species-specific primers and RFLP (restriction fragment length polymorphism) analysis of the 16S-23S ITS region with HpaII....

The exploration of habitats with unusual environment and poorly explored areas such as Antarctica is one of the strategies for discovery of new biologically active substances and/or new producers. The aim of this study was to identify the actinomycetes isolated from the soils of the island Livingston – Antarctica and to investigate their potential...

During the last 20 years, the causative agents of bacterial spot of tomato and pepper have been subjected to many studies and reclassifications. According to the current data, the species are four (X. euvesicatoria, X. vesicatoria, X. gardneri, and X. perforans) and cause similar symptoms in plants but possess different phenotypic properties. This...

Aim: This study aimed to identify the causal agent of tomato plants dieback in greenhouses in different regions in Bulgaria in order to provide relevant advices for growing tomatoes. Material and methods: Bacterial strains were isolated from diseased plant parts and subjected to pathogenicity tests. The scheme of Schaad and BiologTM system were use...

Aim: The aim of this study was to test the effect of different plant extracts against the causal agent of bacterial canker of tomato - Clavibacter michiganensis subsp. michiganensis as potential means for biocontrol. Matherial and Methods: Plants materials from Artemisia absinthium, Ambrosia atemisifolia, Conium maculatum, Clematis vitalba, Datura...

Pseudomonas fluorescens is a widespread species which survive in soil and water with different chemical composition and different climatic conditions. It is a secondary pathogen in nosocomial infections in hospitals because of its strong variability. In phytopathology it is known as a part of the soil resident microflora and as a co-pathogen in var...

Mushroom diseases can be caused by bacteria from genera Pseudomonas, Burkholderia, and Janthinobacterium. The paper deals with bacterial rot of Agaricus bisporus, which was observed in Bulgaria in 2012. The symptoms included large brown to black spots of the hood and the stipe, and crumpled underlying tissues. Pathogenicity tests, major differentia...

Pseudomonas syringae pv. syringae is polyphagous on different grass, herbaceous, shrub and wood plants from families Oleaceae, Rosaceae, Anacardiaceae, Salicaceae and Fabaceae, causal agent of bacterial blight disease. The pathogen is responsible for significant losses of fruit and berry crops worldwide, decreasing the quality and the quantity of t...

extinction and has been thus put under a regulated regime for conservation. However, its natural fields in Bulgaria continue to deteriorate, one of the reasons being contamination of rivers with industrial waste. The plant has been long known not to suffer diseases. In the period 2006–2011, however, diseased bulbs with symptoms of bacteriosis were...

This study aims to characterize 136 Xanthomonas strains causing bacterial spot of tomato and pepper from different regions in Bulgaria and Macedonia. Three species were identified by PCR with species-specific primers. Xanthomonas vesicatoria affects tomato and pepper and is the dominant species in Bulgaria on tomato while Xanthomonas euvesicatoria...

Tomato fruits with typical symptoms of bacterial scab in tomato fields in the region of Plovdiv in 2011 were analyzed. Isolation plates contained mono-morphological, non-pigmented bacterial colonies which were not typical for the expected disease agents of genus Xanthomonas. The bacteria possessed pathogenic potential and were identified as Stenotr...

Summer snowflake /Leucojum aestivum L./ is a medical bulbous plant which belongs to family Amarillydaceae. It is wild-spread as natural populations in Bulgaria and a valuable source of galantamine. A few virus and fungal diseases have been described on plants of family Amaryllidaceae but only fungal pathogens on summer snowflake. This paper is the...

This paper presents an analysis of the phytopathogenic bacteria with facultative anaerobic growth found in diseased bulbs of onion, garlic, gladiolus, tulip, hyacinth, narcissus, and lily in the period 2003-2011. The isolated strains belong to Pantoea agglomerans, Pectobacterium carotovorum, Ewingella americana, Rahnella aquatilis, Serratia sp. and...

Seventy-one Xanthomonas strains isolated from infected pepper and tomato plants with bacterial spot from Bulgaria and Macedonia were examined in this study. The pathotypes and races of the strains were determined. The pepper-tomato pathotype predominated among Bulgarian strains, whereas the Macedonian strains belonged to the pepper pathotype. On th...

Leucojum aestivum (summer snowflake) is a perennial, wild plant species of medical importance which overwinters as bulbs. Few pathogens have been currently described on summer snowflake but only fungi. In 2006 we found and analyzed diseased bulbs of L. aestivum with symptoms of bacteriosis. We found Bacillus subtilis to be the major disease agent a...

Poinsettia, tulip, and calla lily with symptoms of bacterial diseases were analyzed in this study. Curtobacterium flaccumfaciens was found as a disease agent of poinsettia and tulip, Pseudomonas putida – of calla lily, and Pseudomonas chlororaphis – of tulip. The pathogens were identified by their biochemical characteristics, including the system B...

PVY is one of the most damaging plant pathogens listed in the world top-five viruses affecting field-grown vegetables. The developed control strategies do not seem capable to take into account PVY evolution and to suppress risks of new epidemics. The virus is aphid transmitted in nonpersistent manner in which HC-Pro and CP viral proteins act a key...

The identification of 22 isolates as Burkholderia cepacia and B. gladioli was confirmed by PCR amplification with species-specific primers CMG 16-1, G 16-2, CMG 23-1, and CM 23-2. The strains were characterized phenotypically by BIOLOG metabolic profile, antibiotic susceptibility, and interactions with other microorganisms. A greater metabolic dive...

Bacterial infections of bulbs of onion and gladiolus are a problem with their latent (asymptomatic) progress, the inflicted damages, and the lack of means of control against the causal agents of soft rot (Burkholderia gladioli pvs. alliicola, gladioli). This study was designed to investigate the effect of fumigation with methyl bromide and carbon d...

Serratias are widely distributed in soil, air and water, plant-and animal-associated bacteria. Only Serratia marcescens has been established as a phytopathogen. In this study we isolated phytopathogenic Serratia rubidaea from imported in Bulgaria diseased Holland tulip bulbs. The strains caused hypersensitive reaction in tobacco leaves and were pat...

Burkholderia gladioli was first described as a phytopathogen and later associated with certain pulmonary infections. Plant strains were divided into pathovars (alliicola and gladioli) according to plant host and nutrition differences were established. This paper represents an easy-to-perform molecular method for differentiating plant pathovars of B...

Phytopathogenic isolates of Pseudomonas marginalis, Burkholderia gladioli, Burkholderia cepacia and Burkholderia рyrrocinia from onion bulbs, causal agents of the syndrome "soft rot", were investigated in this study. The isolates were identified by the use of the miniatur-ized identification system Biolog™. The phytopathogenic and metabolic propert...

The use of microorganisms for biological purposes has become an effective alternative to control plant pathogens. Actinomycetes are widely distributed groups of microorganisms in nature and have the capability to synthesize many different biologically active secondary metabolites such as antibiotics, herbicides, anti-parasitic substances etc. The s...

The members of genus Burkholderia are various microorganisms, which occupy surprisingly wide range of ecological niches – soil, water (including marine water), rhizosphere, animals and human. The genus includes over 30 species that are important causes of human, animal and plant diseases, as well as organisms useful in promoting plant growth and bi...