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Questions related from Alex Ignatov
Infected potato plant was negative for PVY, PVX, PVM, PVS. What can it be?
20 June 2024 6,764 3 View
What is the relationship between the maximal density of a bacterial population during anaerobic and aerobic growth for a specific species - a facultative anaerobe?
02 June 2024 4,971 4 View
Spanish slugs choose to feed on some of the most poisonous and spicy plants. Do they become toxic to potential predators due to this? Are there any publications available on this topic?
29 May 2024 3,945 0 View
Gymnosporangium sabinae is a rust fungus known as pear rust. It is a heteroecious plant pathogen with Juniperus sabina (savin juniper) as the main primary (telial) host and Pyrus communis (common...
03 April 2024 1,564 1 View
Has anyone used the second derivative of the bacterial suspension density growth curve to compare the growth of bacterial cultures in a bioreactor?
15 March 2024 5,128 2 View
Physalis rugose mosaic virus (PhyRMV) is a Sobemovirus that causes severe damage to Physalis peruviana L., affecting vegetative parameters, fruit quantity and quality. It was reported in Brasil...
31 January 2024 5,273 1 View
Transcription activator-like effectors (TALEs) from the Xanthomonas (and Ralstonia) are proteins with the remarkable ability to directly bind the promoters of genes in the plant host to induce...
24 January 2024 462 0 View
There are three published different taxonomic level for strains within the same species of Xanthomonas. Pathological variant (pv.) is the most accepted, "variant" (var.) is present for some groups...
30 December 2023 8,699 0 View
Rhizobitoxine, produced by Bradyrhizobium sp. , Rhizobium japonicum, and Robbsia andropogonis, was recognized as an inhibitor of methionine biosynthesis. This compound is phytotoxic to soybean and...
17 November 2023 5,094 0 View
Horsetail (Equisetum arvense) is the plant very resistant to Glyphosate. After weeds were killed by the herbicide, it rapidly propagates and maintains high number per area despite the presence of...
10 August 2023 6,853 2 View
Prof. Van der Wolf with colleagues (2005)* wrote that for "... Clavibacter michiganensis no data on transmission via nematodes are available". Dr. Osdaghi (2022)** in the most recent review of...
05 August 2023 7,819 3 View
Leaves of several plant species lost chlorophyll after infestation by Spanish slugs (Arion vulgaris). Is it specific slug toxin or some specific virus vectored by the slug?
30 July 2023 2,254 5 View
There are many cases of natural transformation by Agrobacterium that gave beneficial phenotypes of agricultural crops. It is reviewed by Desmet, S., Dhooghe, E., De Keyser, E. et al. Rhizogenic...
10 June 2023 5,678 1 View
There are many reports of animal/human - pathogenic Arthrobacter strains. There is a recent report about Arthrobacter woluwensis causing brown blotch disease on white button mushroom. Is there...
08 June 2023 2,029 1 View
Chantal Jeanne Beauchamp with colleagues (1990) (Fungal Catabolism of Crown Gall Opines) described fungi capable to utilize several opines as their sole carbon and nitrogen source. Is it possible,...
24 May 2023 5,434 1 View
Tomato disease (Blue mold of tomato) caused by Penicillium oxalicum was found in Japan at 2009. Umemoto, S., Odake, Y., Takeuchi, T. et al. Blue mold of tomato caused by Penicillium oxalicum in...
25 March 2023 8,124 1 View
"Crazy roots" pathogen, Agrobacterium bv1 with Ri plasmid, change plant roots geotropism. Any idea how the pathogen makes it?
14 March 2023 1,274 10 View
Young cucumber plants in greenhouse nursery have significantly distorted development. Any idea that could cause this symptoms?
26 November 2022 6,589 0 View
Several broccoli plants in one plot have abnormal shoots proliferation - more then 30 shoots above ground. It has obvious underground too - see the pictures. Is it disease or genetic disorder? It...
18 September 2022 4,963 6 View
Some strains of Pectobacterium sp. are known to produce Trimethylamine, responsible for "fishy" smell of infected plants. Such bacteria were very rare in Northern countries until recent years....
25 August 2022 9,234 0 View
Several reports of viroids infection outside thier host plants are sometimes disputed (Serra P, Carbonell A, Navarro B, Gago-Zachert S, Li S, Di Serio F, Flores R. Symptomatic plant viroid...
25 August 2022 2,839 0 View
Tolin S. A. wrote that "PVY has a wide host range among the Solanaceae, including 70 species of Nicotiana and is also found in annual and perennial weeds in 15 or more plant families. " (Tolin, S....
04 August 2022 4,371 4 View
Potato plants with normal growth expressed such symptoms as day temperature arised till 30oC. Do you know such virus symptoms on potato?
03 July 2022 8,903 2 View
Chlorhexidine (Chlorhexidine gluconate, digluconate or chlorhexidine acetate) is an antiseptic that is used in medicine for last 70 years. Is there any experience of Chlorhexidine application to...
18 May 2022 2,545 3 View
Miracle F1 (cauliflower, Bejo Zaden ) was used as Xanthomonas campestris races differential variety with proposed gene R3 (Taylor JD, Conway J, Roberts SJ, Astley D, Vicente JG. Sources and origin...
07 May 2022 7,041 0 View
Gram-negative bacterial pathogens interact with the host cells by using type III secretion systems (T3SS) to inject virulence proteins into cells. NleB effectors are glycosyltransferases that...
02 April 2022 7,489 2 View
There are several reports about seed transmission of Liberibacter solanacearum by carrot seeds. (Bertolini E, Teresani GR, Loiseau M, Tanaka FA, Barbé S, Martínez C, Gentit P, López MM, Cambra M....
24 January 2022 712 0 View
Young tomato plants in the greenhouse nursery have rotted the middle part of the leaves. The pathogen is obviously systemic (vein-spreading). Is it familiar to anybody?
23 January 2022 1,999 7 View
Several tomato plants in the hydroponic greenhouses are dwarf, bushy, with changed flowers (see pics), no fruits formed from the changed flowers. They are free of usual viruses. What can it be? I...
21 January 2022 3,031 8 View
Phytoplasma seed transmission is a controversial issue despite some evidence: Phytoplasma Transmission by Seed: Transmission and Managemen... Nečas T, Mašková V, Krška B. The possibility of ESFY...
15 January 2022 9,647 3 View
Microbacterium paraoxydans is known as a pathogen (Laffineur K, Avesani V, Cornu G, Charlier J, Janssens M, Wauters G, Delmee M. Bacteremia due to a novel Microbacterium species in a patient with...
08 December 2021 1,052 4 View
Viruses and viroids that are not causing symptoms on their initial host plant are described by the terms “latent”, “cryptic” or “symptomless” and represent 6% and 2% of the classified plant...
01 December 2021 7,370 4 View
Spray-induced gene silencing, SIGS, is tested for plant diseases control. Is there any results on dsRNA formulation trials that showed long life for dsRNA in a product and an efficient transport...
30 July 2021 4,950 5 View
Potato plants have vein necrosis (like PVY-NT) as first symptoms (3-5 day DPI), later it turns to nectotic spots and leaves die in 10-14 days after first symptoms.
18 June 2021 2,754 7 View
About 1/4 of field was affected by white heads symptoms. What can it be? Temperature range was high: 5 (night) - 30oC (day) within 4 last weeks.
25 May 2021 6,390 4 View
It has been asked before for physalis, potato and tomato plants. Young tomato seedlings grown at room temperature (+20-22oC) and low humidity (65-70%) have symptoms similar to edema. There is no...
03 April 2021 9,112 8 View
Geotrichum candidum is emerging plant pathogen of tomato, citrus, sugar beet, potato, etc. Is it a mostly post-harvest pathogen or can be harmful in field as well? Thornton CR, Slaughter DC,...
15 October 2020 6,708 12 View
Clavibacter michiganensis susp. michiganensis was recovered from damaged lettuce seedlings in greenhouse and confirmed by PCR with two different methods. I have heard about natural infection of...
24 July 2020 295 6 View
Potato plants free of 5 common viruses (PVY, PVX, PVS, PVM, PLRV) have unusual symptoms. What can it be?
05 June 2020 6,971 19 View
It is stated in https://www2.ipm.ucanr.edu/agriculture/tomato/tomato-yellow-leaf-curl/ that TYLCV can infect a wide range of plant species, including peppers (Capsicum annuum), eggplants,...
21 May 2020 1,991 3 View
I have met some evidence that Mycoplasma hyorhinis (Firmicutes, Mollicutes) bacteriophage could infect Pseudomonas syringae (gamma-proteobacteria). Those two hosts are very distant taxonomically....
18 May 2020 3,799 0 View
Barley plants, local winter cultivar Dostoynyi has leafspots, what can cause the disease? 3 weeks ago field was treated by Tribenuron-methy 75%, 0.02 g per ha. Seeds were treated by Tebuconazole....
16 May 2020 568 0 View
Lettuce plants in hydroponics (nutrient solution is under control and has verly low bacterial count) have symptoms of leaf base black necrosis. It is not a soft rot. Symptoms are low developing,...
28 March 2020 4,024 6 View
Cucumber fruit was rotted at cool storage and fungi had such strange bodies. Can anybody name it?
03 March 2020 3,807 4 View
Low accumulation of Boron (B) cause physiological damage in many plants. High concentration of soluble Ca in soil (over 6 g/kg) and acidic pH (4.5-5) prevent accumulation of B despite sufficient...
25 January 2020 5,353 3 View
Greenhouse cucumber plants in greenhouse (hydroponics) with normal growth and development have yellow veins on well-developed leaves. What can be the reason: virus or physiological disorder?
25 January 2020 6,050 4 View
Carrot plants suffer from acute B-deficiency (
27 December 2019 6,673 3 View
Carrots have symptoms of oxidative surface browing ( Chubey BB, Nylund RE. Surface browning of carrots. Canadian journal of plant science. 1969 Jul 1;49(4):421-6. Dorrell DG, Chubey BB....
07 December 2019 4,479 6 View
Tomato plants have clear chlorosis on young leaves and necrotic lesions at the eges of affected leaves. Is it physiological disorder, frenching disease, or virus infection?
09 November 2019 9,140 2 View
Acute oak decline (AOD) is a relatively newly described disease. Symptomatic trees are characterised by stem bleeds, necrotic lesions in the live tissue. Several abiotic and biotic factors can...
09 November 2019 9,374 0 View
Tomato plant have severe damage of fruits and young leaves. Mosaic pattern on leaves and necrotic symptoms on fruits, leaves, and petioles. Its it Tomato brown rugose fruit virus ? I have seen...
06 November 2019 6,160 18 View
Tomato plants have severe symptoms of necrotic spots starting from leaf base. Is it Tomato spotted wilt virus (TSWV) or other variants are possible?
29 October 2019 1,253 6 View
Tomato split stem and bumps symptoms are usually linked to environmental stresses. Some reported about correlation with Fusarium, Verticillium wilt or Rhizoctonia root infection. Is there any...
27 October 2019 364 3 View
Erwinia billingiae was found in association with trees (Mergaert J, Hauben L, Cnockaert MC, Swings J. Reclassification of non-pigmented Erwinia herbicola strains from trees as Erwinia billingiae...
18 October 2019 4,669 11 View
There is a task to identify rapidly current variants of potyviruses in potato and tomato plants. What would yo recommend - NGS or Sanger method to make it faster? If NGS, what method shell we use...
07 October 2019 9,677 2 View
Beet (Beta vulgaris) and potato have many common pathogens ( Rhizoctonia solani, Streptomyces scabies, Pectobacterium atrosepticum, etc.). Can Phytophthora infestans cause disease on beet...
25 July 2019 2,241 5 View
We found a tomato genotype that had large area of leaves covered by Phytophthora infestans sporulating mycelium without any chlorosis or necrosis at least during one week after inoculation...
24 July 2019 1,803 4 View
Potato plant positive for PVYn has extended necroses on stem as well as on leaves. Is it typical for this virus or it can be a new strain of PVY?
21 July 2019 7,121 11 View
Pseudomonas corrugata causes pith necrosis of tomato, diseases of chrysantemium, geranium plants, isolated from roots of other crops, and applyed as biocontrol method against plant pathogenic...
23 May 2019 9,588 13 View
Pseudomonas syringae pv. aptata is a leaf blight/vascular pathogen of sugarbeet, sunflower, cucurbits, lettice, etc. It was isolated from cucumbers (CABI report). Do you know any reports about...
23 May 2019 2,733 2 View
Leaves of plants are cup-shaped and have yellow areas between veins. Is it Cucumber mosaic virus or something else?
23 January 2019 4,299 8 View
I am looking for any data on Maxifort tomato rootstock reaction to Clavibacter michiganensis sbsp. michganensis. Maxifort is resistant to several pathogens...
12 January 2019 3,667 0 View
Young rose plants have chlorosis on leaves and slow growth comparing to healthy ones. What is the reason? Greenhouse plants are grown under controlled (optimal) temperature, humidity, light, and...
10 January 2019 9,370 11 View
Potato virus S causes mild or no symptoms in most potato varieties. It is common in potatoes in many regions and sometime cause 10-20% of yield losses (no reference). Field-grown potatoes are not...
29 November 2018 7,907 7 View
Thielaviopsis basicola is common storage pathogen for carrot roots Moulds that should be better known: Thielaviopsis basicola a... Is there any efficient treatments against the pathogen suitable...
05 October 2018 2,877 12 View
Nuts of Corylus avellana L. have necrotic lesions (pics). What can be a casual agent? Such disease is rather usual in local forest.
12 August 2018 5,313 5 View
The EU Court of Justice has ruled that plants created using novel genome editing methods will be classed as genetically modified organisms and therefore have to follow the strict EU guidelines for...
29 July 2018 3,861 34 View
Seedlings of commercial sunflower hybrid show chlorosis and browning of cotyledons for over 50% of plants. Others are green, but looks smaller. What can be the reason: disease, genetic disorder,...
17 July 2018 1,794 32 View
Some strain of Curtobacterium have toxic effects on inoculated plants. Does anybody study toxins of these species?
09 July 2018 7,210 2 View
Sunflower young plants show retarded growth, surface necrosis and cracks of undersoil stem part, necrosis of leaf petioles, young top leaves are dead. There is no evidence of bacterial or fungal...
10 June 2018 9,853 8 View
It is known that many pathogenic/parasitic microbes increase resistance to biocides if penetrate host cell. What would happen with Phytophthora infestans?
21 April 2018 4,076 10 View
I have isolated from water some strange-looking colonies on YDC medium. In fact they are dark violet. Do you have any idea about taxonomic position of this bacteria?
25 February 2018 7,999 5 View
I have isolated some highly aggressive xanthomonads from vascular system of tomato plants. Tomato were grown in hydroponic culture and had symptoms similar to bacterial cancer (wilting, leaf...
15 December 2017 1,140 2 View
P. aptata is known as causing agent of leaf spot and leaf blight disease of beets. Is it capable to colonize vascular system of plant, and, particularly, root? So far, I could find only one...
17 September 2017 3,636 5 View
Pantoea ananatis is an emerging plant pathogen in Russia. It was found on rice, wheat, soybean and cucumber plants. Does anybody know about P. ananatis occurrence on sugar beet? Related pathogen,...
30 March 2017 6,845 11 View
It is known that bacterial Wetwood disease (Enterobacter spp., Klebsiella spp., Pantoea spp., etc.) can affect apple tree. It is spreading now in private gardens in Russia as well as in forest...
04 September 2016 6,566 4 View
Black spots in the bottom of leaves turn into necrosis, leaves turn yellow and die. Stem necrotic lesions spread along veins to fruits and cause fruit necrosis and soft rot. Disease is...
09 August 2016 4,881 15 View
I know about several evaluations of apple cultivars for bacterial canker (P. syringae) reaction, like http://link.springer.com/article/10.1023/A:1008652931035. The results were not optimistic. Is...
19 May 2016 3,697 5 View
The symptoms shown on attached pictures were found among tubers of one commercial stock of potato seeds. What is this? Nematode, insects, or fungus? Tubers were sent to experts but, maybe,...
06 May 2016 4,380 11 View
I need some seeds of Pacifica F1 cabbage from Sakata. This cultivar is listed in catalogs of several companies, but they do not have any seeds now. Can anybody help?
07 March 2016 7,608 5 View
Our major staple crops: bread wheat, potato, oilseed rape, etc. are polyploids and/or alloploids. They still have smaller genome than plant with largest one - Paris japonica with 150 billion bp....
21 February 2016 5,881 12 View
Cai Rongman in his PhD dissertation hypothesized that highly virulent P. syringae crop pathogens with narrow host range might have evolved after the advent of agriculture from ancestral P....
24 October 2015 7,231 6 View
There are many Alternaria pathogens that produce host-specific toxins. Alternaria host-specific toxins are classified in three groups in terms of the primary site action. First group of toxins...
06 August 2015 8,223 2 View
Bacterial wetwood, also known as slime flux, is caused by an infection of one or more of several bacteria. Enterobacter cloacae (Erwinia nimipressuralis) has been implicated as the cause of...
22 July 2015 2,064 5 View
Tomato hybrid plants show slight yellowing and deformation of younger leaves. The symptoms occur from seedlings to maturing stage. Affected plants grow slower. Is it mild virus or genetic...
13 July 2015 6,417 2 View
For the first time it looks like herbicide damage. Young leaves growth retardation and yellowing have been noticed at the same plot last year, but at later stage of plant development. This year,...
08 July 2015 8,668 29 View
GAF1 is 4-Formylaminooxyvinylglycine, a herbicidal germination-arrest factor from Pseudomonas rhizosphere bacteria. It is present in a number of soil bacteria, and applied for control the numerous...
30 April 2015 5,931 3 View
Hiroshimana (Brassica rapa) is a Japanese leafy vegetable with specific morphology and good adaptation to winter growth season (in Japanese winter). There are several opinions about its origin....
30 April 2015 3,098 3 View
EPPO Data Sheets on Xanthomonas vesicatoria has mentioned that it was found on fruits of potato. (http://www.eppo.int/QUARANTINE/bacteria/Xanthomonas_vesicatoria/XANTVE_ds.pdf) Has anybody met...
21 February 2015 665 17 View
Contaminated seeds (inner infection) became a main factor of new pathogens entrance to agricultural areas, and yield losses caused by bacteria and viruses. Is there any reliable seed treatment...
20 February 2015 1,217 11 View
Irrigation water is a source of numerous plant pathogens. I know UV-radiation, Chlorine -based compounds treatment, sand filtration. They are rather expensive and are not applied in field. Is...
15 February 2015 2,466 22 View
High energy microwave affect iliving beings mainly through termal effect. What is the mechanism of low dose microwave (300 MHz - 300 GHz electromagnetic field) effect on organism: membrane...
18 January 2015 9,778 8 View
There are many articles about root-associated bacteria capable to protect plant from pathogenic fungi causing root rot of cereals. Many of this bacteria belong to plant pathogenic taxa...
30 December 2014 2,542 6 View
Symptoms have appeared as small white spots, rapidly growing and leaves were destroyed in 4-5 days. Rapid systemic spreading was observed as well.
02 September 2014 1,601 18 View
I have found recently yellow-pigmented bacterium that cause canker of Physalis leaves at 25-30oC and rapid blight at 35oC. This bacterium cause no symptoms but colonyze plant leaves at
29 August 2014 7,119 4 View
What shell we expect and test plants before founding new grapevine plantations? The list includes 14 viruses: Alfalfa mosaic virus; Arabis mosaic virus; Broad bean wilt virus; Grapevine Algerian...
27 August 2014 4,017 10 View
Chlorophyll f is a type of chlorophyll that absorbs further in the red (infrared light) than other chlorophylls (Chen, M. .; Schliep, M. .; Willows, R. D.; Cai, Z. -L.; Neilan, B. A.; Scheer, H. ....
20 April 2014 8,467 4 View
"The ancient pathogen Pithovirus sibericum (class of giant viruses) was discovered buried 30m down in the frozen ground. The virus infects amoebas. The last time it infected anything was more than...
05 March 2014 3,639 4 View
Cms (potato ring rot pathogen) is a close relative of bacteria with life cycle linked to nematodes (Cm subsp. insidiosum, Leifsonia poae, Rathayibacter sp.). Cms is quoted as nematode -...
12 February 2014 4,761 8 View
Agrobacterium bv1 with cucumopine Ri plasmid causes root mat disease of cucumber and tomato in greenhouses. I cannot find any efficient way to reduce the disease on plants and remove the pathogen...
11 February 2014 5,740 14 View
Economic threat of bacterial diseases of cereals is a highly disputed. Some data show potential loss about 40% of yield, others - less than 10% of total losses caused by all diseases
01 February 2014 2,903 2 View
There are several examples of plasmids carryng pathogenicity genes and turning common bacteria into emerging plant pathogens. One of them is "Recurrent outbreaks of root mat in cucumber and tomato...
01 February 2014 9,390 0 View
More and more opportunistic bacterial pathogens like Serratia, Pantoea, E. coli are isolated from plants and cause new plant diseases. Is there an increasing risk for people?
01 February 2014 2,552 8 View
Erwinia amylovora is a new pathogen for Russia and other countries of the FSU. In Kazakhstan, about 60% of apple orchards are infected. But, in Russia, with cold climate, there are some evidence...
01 February 2014 2,930 11 View
Agrobacterium tumefaciens can cause diseases of annual crops - cabbage, beet, carrot, but those diseases occure in field in Russia and Ukraine once in several years. Is there any examples of more...
01 February 2014 4,598 5 View
We study interaction of physcomitrella patens with plant pathogenic bacteria and found high level of plant reaction diversity to some strains in different experiments. Is it a result of somaclonal...
21 January 2014 8,895 4 View
Some DNA sequences localized between CRISPRs repeats of plant pathogenic bacteria are more similar to plant pathogenic viruses than to bacteriophages. Does it mean that plant viruses have infected...
18 January 2014 7,441 6 View
We are reviewing presence of Xanthomonas oryzae in Russia and the former USSR, and found that some strains obtained originally as X. oryzae are X. campestris (MLST analysis), including strains...
18 January 2014 6,993 2 View
Pseudomonas syringae pv. syringae and pv. atrofaciens cause diseases of wheat and other cereals, most harmful at early spring on winter crops. It was a problem in the USA from 1960-70 (Otto, 1976,...
10 January 2014 1,908 3 View
Wheat and barley plants infected by wheat streak mosaic virus and other viruses with clear yellow and even necrotic lesions have very small population of bacteria (Pantoea sp., Pseudomonas sp.)...
09 January 2014 930 4 View
Pantoea spp. are the most common bacteria isolated from bacterial leaf lesions of small grains, but there is no data about pathogenic Pantoea species on those crops. Pantoea stewartii/P. ananatis...
05 January 2014 9,166 19 View
Andree Hubber (2004) described effector-coding genes with signal aa for both T3SS and T4SS.
24 November 2013 6,455 3 View
Has anybody confirmed presence of N-gene of resistance to TMV in tobacco accession CV-58 (PI 551316 Nicotiana tabacum L. SC 72, NC403, T.W. Graham, J.F. Chaplin, Z.T. Ford, R.E. Currin. 1974....
01 January 1970 2,830 2 View
