Alexsander Ignatov
Doctor of Biological Sciences
Professor,
agrobiotechnology Department
"Healthy planting material is the basis of food security"
1982-1987
Graduated from Moscow Agricultural Academy named after K. A. Timiryazev (Moscow Timiryazev Agricultural Academy), Agronomy Faculty, diploma with honors, specialization - plant protection.
1987-1989
Senior laboratory assistant of the all-Russian Research Institute of Phytopathology.
1989-1992
Postgraduate study at all-Russian Research Institute of Selection and Seed Production of Vegetable Crops.
1993-1998
Senior researcher of all-Russian Research Institute of Selection and Seed Production of Vegetable Crops.
1994-1995
Traineeship at Horticulture Research International – Wellesbourne, UK.
1997-1998
Post-doctoral studies at the National Institute of Vegetable, Ornamental Plants and Tea (NIVOT), Japan.
1998-2015
Senior researcher, leading researcher at the Center of "Bioengineering" of the Russian Academy of Sciences (Federal Research Center of Biotechnology of the Russian Academy of Sciences).
2004-2005
Post-doctoral studies at the University of Nebraska (Lincoln) USA.
2009-2015
Head of the group and laboratory of molecular Phytopathology of the center of "Bioengineering" of the Russian Academy of Sciences.
2010-08.2013
Professor of the Department of Plant Protection of the Russian State Agrarian University - Moscow Timiryazev Agricultural Academy.
2010-02.2015
Head of the laboratory of bacterial diseases of plants of the all-Russian Research Institute of Phytopathology.
2011-present
Deputy Director for scientific work of the Research Laboratory "Phytoengineering».
2011-present
Chairman of the scientific and technical Council of the Association of seed potato producers, member of the scientific and technical Council of the Rosselkhoznadzor in the section of quarantine phytosanitary surveillance and seed control, expert of the Russian Foundation for basic research and the Russian Science Foundation.
2013-2015
Head of the Department of Botany, Plant Physiology and Agrobiotechnology of Agrarian and Technological Institute of RUDN University.
2015-present
Professor of Agrobiotechnology Department of RUDN University.
Teaching
Lecture course for bachelors and masters of the direction “Agronomy”:
- “Bacterial diseases of plants”,
- “Molecular diagnostics in plant protection”,
- “Methods of Phytopathology”
Science
- New types of resistance of cruciferous plants to bacteriosis were discovered. It is known that the harvest of different types of cabbage is rarely preserved without loss, sometimes losses reach 100%. The reason is latent or partially manifested defeat by bacterial infection. The use of new types of resistance (race-specific and systemic) can significantly reduce crop losses such as cabbage, and avoid multimillion losses of agricultural holdings.
- The stability of the genetic collections of cabbage crops of the N. I. Vavilov All-Russian Institute of Plant Genetic Resources was assessed. The results made it possible to obtain new donors for breeding varieties for resistance to phytopathogens.
- Collections of plant pathogenic bacteria were created and their genetic diversity was studied by methods of whole genome sequencing. Such bacteria on plants mutate, move from one culture to another, where they have not met before, which greatly complicates the diagnosis and the adoption of timely protection measures. The study will facilitate the diagnosis of bacterioses - especially those that have not previously met.
- New bacterial pathogens - new genotypes of the species Clavibacter spp., Xanthomonas spp. were described for the first time. Representatives of these two taxa are pathogenic and have a great genetic diversity. This often blurs visible symptoms of a typical lesion on the plant and makes it difficult to diagnose. The described new genotypes were not previously encountered on the usual host plants. On the basis of the obtained results, the methods of controlling phytopathogens have been improved.
- Pathogenic bacteria Dickeya solani, D. dianthicola, D. dadantii, Pantoea ananatis, Agrobacterium bv1 (root mat), Xanthomonas gardneri, X. euvesicatoria, X. arboricola (pathotype of grain crops) were revealed for the first time in Russia. Bacterioses of grain crops will lead not only to a quantitative decrease in yield but also to a deterioration in the quality of flour and its by-products because of the presence there of the products of their metabolism. The spread of bacteria with seed material leads to the fact that new prototypes are imported, the fight against which is extremely difficult. The obtained results allow more effective control of quarantine services, preventing the introduction of infectious diseases and agricultural pests into the territory of the Russian Federation.
- Biological methods of plant protection with the use of bacteriophages and bacteria-antagonists were developed. The developed methods allowed to expand the range of biological methods of fighting against bacteriosis.
Scientific interests
- Epidemiology of bacterial diseases of plants.
- Evolutionary pathway and diversity of bacterial symbionts of insects and mites.
- Vascular bacteriosis of cabbage in Russia - causes of epiphytotics, methods of protection and sources of selection for disease resistance.
- Determination of phytopathogenic bacteria affecting crops, crucifers and solanaceous crops.
- New model objects for studying the interaction of plants and phytopathogenic bacteria.
- A new type of plant diseases caused by non-pathogenic microorganisms-producers of phytotoxic substances.
- The spread of bacterial and phytoplasmic plant diseases in Russia.
- The spread of causative agents of bacterial diseases of potatoes in Russia.
- The resistance of plants to phytopathogens.
- Xanthomonas, Pseudomonas, Clavibacter, Dickeya, Pectobacterium, Sclerotinia, Potyvirus (detection and diagnosis of phytopathogens, plant-pathogen interaction, new methods of plant disease control).
Since 2013, many hydroponic cucumber (Cucumis sativus) and tomato (Solanum lycopersicum) crops in the Russian Federation have been affected by a root disorder known as “root mat” or “crazy roots.” The symptoms include extensive root proliferation within rockwool propagation cubes. Crazy roots have been reported in United Kingdom, France (Weller et al. 2000), and Japan (Sawada and Azegami 2014), where it caused significant reductions in marketable yield. The causal agent of this disease was shown to be wild-type Agrobacterium radiobacter biovar 1 strains harboring a Ri-plasmid (Weller et al. 2000). In the Russian Federation, crazy roots were found for the first time in winter 2013-2014 in the Novgorod Region on cucumber and tomato plants grown hydroponically in rockwool. The disease incidence in these outbreaks ranged from 50 to 100%. Rhizogenic strains of A. radiobacter biovar 1 were isolated from affected roots, cucumber vines, tomato stems, internal tissue of fruits and seeds, rockwool, and irrigation water pumped from a local river during cultivation. Plant samples were surface-sterilized, homogenized, and 10-fold serial dilutions of the resulting suspensions were plated onto RS medium (Moore et al. 2001). Liquid from rockwool and water samples were used for serial dilutions and isolation of bacteria on RS medium as well. Isolation plates were incubated for 5 days at 28°C until bacterial colonies developed. Colonies consistent with the expected morphology of Agrobacterium spp. on RS medium were subcultured on yeast dextrose calcium carbonate agar (YDC). Putative Agrobacterium isolates were confirmed by real-time-PCR assay as described previously (Weller and Stead 2002). In 2014, cucumber and tomato plants with similar symptoms were obtained from glasshouses in five regions of the Russian Federation. In Rostov and Novosibirsk regions, virulent Agrobacterium radiobacter bv1 was also isolated from irrigation water during cultivation. The identity of all recovered isolates (n = 36) was confirmed by biochemical tests as previously described (Moore et al. 2001) and real-time-PCR assay (Wel\ler and Stead 2002). Suspensions of 10 isolates of the bacterium from 6 locations, deposited in the Russian Collection of Plant Pathogenic Microorganisms (Russian Institute of Phytopathology) as Ag2701 to Ag2710 were inoculated into seedlings of susceptible varieties ‘Marfinskii’ (cucumber) and ‘Gavrosh’ (tomato), as described by Weller et al. (2000). Symptoms were seen on all inoculated plants four to five weeks after inoculation, as increased root production across the propagation rockwool cube surface. Rhizogenic Agrobacterium strains were reisolated from all the slabs with symptomatic plants. No symptoms developed and no rhizogenic Agrobacterium radiobacter strains were isolated from control plants. Sequence typing of the housekeeping genes atpD, glnA, and recA was done according to the protocol and primers described by Puławska et al. (2012) for strains Ag2701-Ag2706 from six regions in Russia. Sequences were deposited in GenBank (atpD, glnA, and recA sequences as Accession Nos. KT831395 to KT831400, KT831401 to KT831406, and KT831407 to KT831412, respectively). BLAST analysis revealed that the sequenced genes for the recently isolated Agrobacterium spp. had 98 to 100% homology to those of A. radiobacter strain NCPPB 2659. This is the first record of rhizogenic Agrobacterium radiobacter causing root mat symptoms in cucumber and tomato in the Russian Federation.
Symptoms of crown gall were observed in 9 of 15 surveyed vineyards located along Black Sea coast of Russia. Sampled tumor tissue was placed in a mortar and pestle for maceration. Serial dilutions of the resulting suspension were plated onto RS medium described by Roy and Sasser (1983). Isolation plates were incubated for 5 days at 28°C until bacteria developed. Colonies were consistent with morphology expected of Agrobacterium spp. On RS medium (opaque red center, translucent margin, mucoid) were purified on yeast dextrose calcium carbonate agar (YDC). Sixty-nine putative Agrobacterium isolates were confirmed by PCR with consensus primers virD2A/2C from the virD2 gene (Haas et al. 1995). Isolates—identified by PCR and producing tumors on indicator plants (carrot, red beet, sunflower) and on grapevine plants in 30 days after needle prick inoculation—were subjected to additional biochemical and physiological tests for Agrobacterium spp. (Moore et al. 2001). The tests included evaluation of 3-ketolactose production, alkaline reaction in litmus milk, growth on 2% and 5% NaCl, growth at 36°C, acid production from erythritol and melezitose, and alkali production from malonic acid and l-tartaric acid. Bacteria reisolated from inoculated grapevine plants were similar to original isolates in PCR test and 3-ketolactose production. The PGF/PGR primers amplifying the chromosomal polygalacturonase gene pehA (Szegedi and Bottka 2002) were used to identify A. vitis isolates and differentiate them from A. tumefaciens. Based on PCR, 18 of 69 tested isolates belonged to A. vitis and showed results of biochemical tests consisted with this species. In addition, for nine isolates, DNA sequence analysis of the housekeeping genes dnaK and trpE confirmed the isolates as A. vitis (Aujoulat et al. 2011). Sequences were deposited in GenBank as Accessions Nos. KT831413 to KT831421 for the dnaK gene and KT831422 to KT831430 for the trpE gene. Sequences were compared with corresponding genes of sequenced strain Agrobacterium vitis S4 (Accession No. CP000633.1). BLAST analysis revealed 99% homology for dnaK and 100% homology for trpE gene. This is the first documented Russian record of Agrobacterium vitis.
In recent years, the damage caused by bacterial pathogens to major crops has been increasing worldwide. Pseudomonas syringae is a widespread bacterial species that infects almost all major crops. Different P. syringae strains use a wide range of biochemical mechanisms, including phytotoxins and effectors of the type III and type IV secretion systems, which determine the specific nature of the pathogen virulence. Strains 1845 (isolated from dicots) and 2507 (isolated from monocots) were selected for sequencing because they specialize on different groups of plants. We compared virulence factors in these and other available genomes of phylogroup 2 to find genes responsible for the specialization of bacteria. We showed that strain 1845 belongs to the clonal group that has been infecting monocots in Russia and USA for a long time (at least 50 years). Strain 1845 has relatively recently changed its host plant to dicots. The results obtained by comparing the strain 1845 genome with the genomes of bacteria infecting monocots can help to identify the genes that define specific nature of the virulence of P. syringae strains.
Xanthomonas campestris pv. campestris, the causal agent of black rot of crucifers, is considered the most destructive pathogen of crucifers worldwide. The pathogen was one of the first bacteria shown to be seedborne and seed transmitted. Interestingly, however, the disease seldom occurs and causes little damage in cool, temperate climates, but causes severe losses in glasshouse transplant production and in warm, subtropical climates. Although X. campestris pv. campestris survives long-term in cruciferous weeds, over winters in infected plant debris, and survives short-term as an epiphyte, the most important primary source of inoculum is seed. Management of black rot is therefore achieved primarily by sanitation and sowing pathogen-free seed.
Bacteriophage vB_PpaP_PP74 (PP74) is a novel virulent phage that infects members of the species Pectobacterium parmen-tieri, a newly established species of soft-rot-causing bacteria in the family Pectobacteriaceae, derived from potato-specific Pectobacterium wasabiae. vB_PpaP_PP74 was identified as a member of the family Podoviridae by transmission electron microscopy. The phage has a 39,790-bp dsDNA genome containing 50 open reading frames (ORFs). Because of the absence of genes encoding toxins or lysogeny factors, PP74 may be considered a candidate phage for pathogen biocontrol applications. The genome layout is similar to genomes of T7-like phages within the subfamily Autographivirinae, and therefore, func-tions can be attributed to most of ORFs. However, the closest nucleotide sequence homologs of phage PP74 are unclassified Escherichia phages. Based on phylogenetic analysis, vB_PpaP_PP74 is a sensu lato T7-like phage, but it forms a distant subgenus group together with homologous enterobacterial phages.
Draft Genome Sequences of New Genomospecies “Candidatus Pectobacterium maceratum” Strains, Which Cause Soft Rot in Plants. Investigation of collections of phytopathogenic bacteria has revealed some strains distinct from known Pectobacterium spp. We report here the draft genome sequences of five such strains, isolated during the period of 1947 to 2012. Based on comparative genomics, we propose a new candidate genomospecies of the genus Pectobacterium, “Candidatus Pectobacterium maceratum.”