Rot Of Potato Tubers Research Articles

Suppression of Fusarium dry rot of potato using beneficial bacterial treatments

Fusarium dry rot affects up to 60% of potato tubers during storage. Pathogen resistance development to synthetic chemical fungicides is a main contributing factor. Previous work has demonstrated the use of bacterial antagonists against plant pathogens. In this study, bacteria isolated from disease suppressive composts were tested to evaluate their antagonistic activity against F. sambucinum in vitro, as well as to assess their ability to reduce Fusarium dry rot of potato tubers. To identify the potential implication of antifungal compounds in their inhibitory activity, bacterial extracts were produced and assayed against F. sambucinum mycelial growth and conidial germination. In vitro results showed that all tested bacteria suppressed F. sambucinum mycelial growth over six days of incubation. When testing the bacteria against potato dry rot, 30 of 32 bacteria reduced the symptoms of the disease at the higher bacterial concentration tested. The combined in vitro and in vivo studies indicated Bacillus subtilis B9–8, Pseudomonas moraviensis F9–6, Pseudomonas koreensis F9–9, and Pseudomonas gessardii M9–16 were the most effective strains. Extracts from these four bacteria were able to inhibit mycelial growth and/or conidial germination of the fungal mold. Results from this study suggests that multiple antagonistic bacteria may be useful in controlling Fusarium dry rot on potato tubers. Extracts from the four most effective bacteria indicated that antibiosis was a main mode of action against F. sambucinum.

First report of Neoscytalidium dimidiatum causing tuber rot of potato in Turkey

First report of Neoscytalidium dimidiatum causing tuber rot of potato in Turkey

Screening of quorum-quenching bacteria associated with rhizosphere as biocontrol agents of Pectobacterium carotovorum subsp. carotovorum

The communication system in bacteria is mediated by chemical signal molecules in a process that is known as quorum sensing. Inactivation of this process, called quorum quenching (QQ), could be a potential strategy for controlling plant pathogenic bacteria. This study aimed to identify QQ bacteria as biocontrol agents against Pectobacterium carotovorum subsp. carotovorum (Pcc). For this purpose, the ability of obtained isolates from the rhizosphere to degrade acyl-homoserine lactone signalling molecules was investigated in the presence of gamma-caprolactone. In vitro and GC-MS analyses confirmed the consumption of GCL by some isolates which identified as species of Pseudomonas, Bacillus and Erwinia based on their phenotypic characteristics and partial 16S rRNA gene sequences and, Pseudomonas rhizosphaerae was introduced as QQ agent. Also, in vivo evaluation, Bacillus pumilus, Pseudomonas fluorescens and Pseudomonas sp. reduced soft rot in potato tubers by 98% as compared to the control inoculated with Pcc.

First report of Enterobacter cloacae as a causative agent of soft rot disease in dragon fruit (Hylocereus undatus) stems in Peru

The objective of the present research was to identify the causal agent of soft rot disease in the stems of pitahaya plants (Hylocereus undatus (Haw.) Britton & Rose), also known as dragon fruit, in two production areas of Peru. Typical symptoms observed include rotting and soft consistency in stems, as well as yellowish colourations, which usually begin at the tips and outer edges of the stems and extend until they are completely decomposed. Symptomatic samples of pitahaya stalks were collected from two commercial fields, the first from the district of Independencia, Pisco, Ica, and the second from the district of Naranjos, Rioja, San Martin. The collected samples were transferred to the phytopathology laboratory of the National Agrarian University – La Molina where 19 bacterial colonies isolated from symptomatic stem tissue were processed. Nine bacterial colonies were selected from the initial 19 for further analysis. The nine selected colonies were gram negative, positive for the catalase enzyme, negative for the enzyme oxidase, and positive for pectinase production, which causes soft rot in potato tubers. These results indicated that these isolates correspond to the Enterobacteriaceae family. According to molecular tests and analysis of the 16s region of ribosomal DNA, all bacteria corresponded to a single taxonomic genus, Enterobacter. This bacterium presented a 99.85% homology with Enterobacter cloacae (accession number MH788982.1). The sequences from the nine selected isolates were entered into GenBank under accession number MN784371. In the pathogenicity test, 100% infection was obtained in the pitahaya stems and plants inoculated with E. cloacae, and the symptomatology that developed was the same as that observed in the two fields from where the samples were collected. Given these results, it can be concluded that E. cloacae is a causative agent of soft rot disease of the stems of H. undatus in the districts of Independencia and Naranjos, and this is also the first report of this bacterium as a pathogen of pitahaya in Peru.

Efficacy of potent antagonistic yeast Wickerhamiella versatilis against soft rot disease of potato caused by Pectobacterium carotovorum subsp. carotovorum

In this study, an antagonistic yeast isolate, Wickerhamiella versatilis was considered as a promising biocontrol agent against Pectobacterium carotovorum subsp. Carotovorum (Pcc) the causal agent of soft rot disease of potato. Antagonistic yeast inhibited the growth of Pcc in vitro, and reducing the soft rot severity of infected potato tubers (cv. Diamant) under greenhouse conditions. Consequently, cellulase and pectinase hydrolytic activities in infected potato tubers with yeast + Pcc were decreased compared with infected tubers with Pcc. The histological characterization of treated potato tubers with antagonistic yeast W. versatilis using scanning electron microscope showed the accumulation of extracellular substances that may induce plant resistant and protects potato tubers from hydrolysis and damages. This study may introduce the possibility of using the antagonistic yeast isolate, as a biocontrol agent against soft rot of potato tubers.

Симптоматика фузаріозної сухої гнилі бульб картоплі

Симптоматика фузаріозної сухої гнилі бульб картоплі

First Report of Potato Tuber Rot Caused by Ditylenchus destructor in Liaoning, China

First Report of Potato Tuber Rot Caused by <i>Ditylenchus destructor</i> in Liaoning, China

First Report of Pseudomonas viridiflava Causing Bacterial Blight on Globe Artichoke in Turkey

The production of globe artichoke (Cynara scolymus L.), which is a major part of Mediterranean cuisine and packs an abundance of nutritional value, has been increasing over recent decades in Turkey. In the spring of 2018, globe artichoke (cv. Sakiz) plants with blight symptoms on outer bracts, dark brown sunken lesion on inner sides, red-brown areas on margins, and small and malformed buds were found in artichoke-growing areas in the Karaburun district of Izmir, Turkey. In some areas, disease incidence was up to 5% of the plants. Several buds in harvest stage exhibiting symptoms were collected from 30-ha artichoke production fields that have heavy soil texture and humid weather conditions and processed to identify the causal agent on 15 artichoke samples. Symptomatic outer bracts showing characteristics of bacterial blight symptoms as well as spines were surface sterilized with 1% NaOCl, rinsed in sterilized distilled water (SDW), and cultured on King’s medium B (KB) for 24 h at 28°C. After incubation, a predominant bacterium was isolated from all samples. Fifteen isolates from independent samples were subjected to biochemical and pathogenicity tests. Round, flat, and blue-green translucent colonies fluorescing under 360-nm UV light when grown on KB medium were observed in all samples taken. The isolates caused soft rot of potato tubers, induced a hypersensitive reaction in tobacco leaves, gave a reaction in the anaerobe respiratory test, and were negative for levan, oxidase, arginine dihydrolase, gelatin hydrolysis, aesculin hydrolysis, and starch hydrolysis. The isolated strains presented the following LOPAT profile: – – + – +. Acid was produced from mannitol, erythritol glycerol, D-sorbitol, D-mannose, and inositol but not from L-tyrosine, D-cellobiose, D-arabinose, and D-trehalose, all of which are typical characteristics of Pseudomonas viridiflava (Lelliott et al. 1966; Schaad et al. 2001). The bacterial identity was further confirmed by amplifying the 16S rRNA gene using the universal bacterial primers 8F and 1492R (Galkiewicz and Kellogg 2008) and gyrase subunit B (gyrB) gene using primers gyrB-Rps/gyrB-Fps (Sawada et al. 1999). The sequences were submitted to GenBank under accession numbers MH763694 for 16S and MK546431 for gyrB. BLASTn analysis of the 1,042-bp amplicon for 16S and 545-bp amplicon for gyrB indicated that it had 99% similarity with P. viridiflava strain 4G1113 (accession no. MG972916) and 100% similarity with P. viridiflava ATCC 13223 strain (accession no. KY612187), respectively. Pathogenicity tests were conducted twice on outer bracts and main stems of artichoke cultivar Sakiz by inoculating 20 µl of bacterial suspension of a 24-h culture in KB medium (1.9 × 10⁹ CFU/ml in SDW). The inoculated plants were placed in a transparent box for 7 days and kept at 25°C and 70% relative humidity. The bract leaves inoculated with only SDW did not develop symptoms; however, the bracts treated with isolated bacterial suspension developed blight symptoms similar to those observed in the field, 7 days postinoculation. The stems inoculated with the isolate also exhibited soft rot symptoms, and the same bacterium was consistently reisolated from both bracts and stems but not from parts of negative control plants. Reisolated bacteria exhibited the same biochemical profile with our isolate, thereby fulfilling Koch’s postulates. P. viridiflava causing a bacterial blight of artichoke bracts was previously reported in Greece (Sarris et al. 2012). To our knowledge, it is the first report of this bacterium causing bacterial blight on leaves and soft rot on stems of globe artichoke in Turkey. Given the availability of climatic conditions, the potential of disease spreading can cause a serious reduction in yield and marketability of this vegetable, which has increasing popularity owing to having high nutritional value, leading to substantial economic losses.

The mechanism of induced resistance against Fusarium dry rot in potato tubers by the T-2 toxin

Potato (Solanum tubersosum L) is the most important non-grain source of human diet for the people living at poverty line. Potato suffers from many notorious biotic stresses, including dry rot caused by Fusarium spp. Treatments of potato tubers with 1 mg L−1 of T-2 toxin produced by Fusarium spp. induced resistance against Fusarium sulphureum by new elicitor-like activity. To investigate the mechanism of induced resistance by T-2 toxin against dry rot of potato, tuber slices were treated with T-2 toxin, followed by the inoculation with F. sulphureum spores. Results in this study showed that the reduction of disease area was linked with higher abundance of reactive oxygen species (ROS) and new phenylpropanoid metabolites. T-2 toxin treatment increased ROS accumulation and induced the activities of enzymes involved in ROS and phenylpropanoid metabolism. At the same time, T-2 toxin treatment also up-regulated proteins involved in ROS and phenylpropanoid metabolism determined by iTRAQ (isobaric tags for relative and absolute quantitation) assay, as well as genes encoding proteins involved ROS and phenylpropanoid metabolism. Taken together, this study provides substantial evidences that T-2 toxin induced resistance related proteins and genes in potato tuber slices to suppress the dry rot severity of F. sulphureum.

Ring Rot Bacterium: An Overview of Its General Characteristics, Pathogenicity Factors and Detection Methods

The aim of this literature review is to provide an overview of recent advances in our understanding of known pathogenicity factors implicated in ring rot disease caused by Clavibacter michiganensis sepedonicus (Cms). Several genetic determinants with possible functions in plant-pathogen interaction were identified. Functional analysis of genes involved in pathogenicity offered us some clues regarding the infectious process. Successful eradication of the ring rot disease relies on prevention by the exclusive use of certified, ring rot-free seed potatoes, sanitation and early detection. An important factor that contributed to the persistence of the ring rot disease in potato cultivation areas in northern Europe and North America is the occurrence of latent infections and limitation of detection technique. Early detection of the bacterium is a fundamental element of eradication program; however, screening tests do not provide the needed information about the potential pathogenicity or virulence of the detected bacteria. Recently developed molecular based detection protocols were demonstrated to be fast, sensitive and specific. Their use could improve the first line screening for ring rot in potato tubers. We anticipate that further genomic studies will allow the identification of pathogenicity or virulence markers useful in the advancement of new diagnostic tools as alternative strategies to the time-consuming pathogenicity tests.

Biological and chemical control for some fungi associated with potato tuber rot

Isolation results from the potato tuber showed appearance of fungi Rhizoctonia solani , Phoma sp (1) and Phoma sp (2) the result also showed great antagonism ability of T.harzianum against isolated fungi under laboratory conditions and Bacillus subtilis showed effective mycelium growth inhibition against isolated fungi bio-pesticides bioassay of Cryptanol and Tobsin _M showed non-significant differences between the fungi in the rates of inhibition percentage .The results of potato disc treated with controlling factors revealed developing dry rot, The biggest inhibition significantly in the development of rot in potatoes disc test was with R. solani and Phoma sp. When they treated with Cryptanol 86.6%, which did not differ significantly from Phoma sp. (2) with Tobsin –M and Phoma sp. (2) and R. solani Phoma sp. (1) When Its treated with T. harzianum 80 % and the lowest percentage of inhibition with R. solani when treated with B. subtilis 53.4% . The results of potato tubers treated with controlling factors reveal that biggest inhibition developing dry rot was with Phoma sp. (2) When Its treated with Cryptanol 95 % which did not differ significantly from the treatment of % sp. (1) with Tobsin-M or Phoma sp. (1) with Cryptanol and Phoma sp. (2) Tobsin –M 92, 90 and 89.1 %, respectively the lowest percentage of inhibition was with Phoma sp. (2) when Its treated with B. subtilis 25 %.

VISUAL QUALITY AND PHYSICAL-CHEMICAL CHARACTERISTICS IN POTATO TUBERS TREATED WITH HYDROGEN PEROXIDE

Unconventional techniques such as the use of visible ultraviolet light (UV-C) and physical treatments have been used to combat post-harvest diseases. Attention has been focused on the use of hydrogen peroxide, but little is known about its effects on the control of bacteria causing soft rot. The objective of this study was to evaluate the incidence of soft rot and physical-chemical and visual characteristics in potato tubers (Solanum tuberosum L.) treated with hydrogen peroxide. The experiment was conducted following a completely randomized design in subdivide plots scheme with four treatments: 0, 50, 100 and 150ppm of hydrogen peroxide whit an inoculated plot and a non inoculated. The visual aspects were evaluated by for to the incidence of soft rot appearance of shoots. pH, titratable acidity (% citric acid), soluble solids content, pulp firmness and total sugar content were used to determine post-harvest quality. Hydrogen peroxide was not effective in controlling soft rot in potato tubers, but increased the metabolic activity of tubers leading to an increase in soluble solids content and reduced in titratable acidity.

Effects of harvest injuries on storage rot of potato tubers infected with Phytophthora infestans

We explored the effects of harvest damage on potatoes infected with Phytophthora infestans in 2015 and 2016. Injured tubers were inoculated with zoosporangia suspensions and incubated at 18°C in the dark for 4 weeks. In 2015 and 2016, 38.5% and 74.4%, respectively, of injured tubers inoculated with P. infestans rotted and hyphal masses were apparent on the tuber surfaces. Tubers in the uninjured group rarely rotted even when there were numerous P. infestans zoosporangia on the inoculated tuber surface. The percentage of rotten tubers in the injured/no inoculation group caused by other types of fungi or bacteria increased rapidly, to approximately 20% within one week; however, there was very little increase during the subsequent incubation. Conversely, the percentage of rotten tubers increased with incubation time in the injured/inoculation group and this phenomenon was significant in 2015. These results imply that not only the presence of P. infestans but also surface harvest injuries affect potato storage rot. Storage rot can be minimized by reducing surface injuries and/or decreasing blighted plant material and the population density of P. infestans in the soil at the time of harvest during commercial potato production.

Isolation, Identification and Preservation of Fusarium Spp. Causing Dry Rot of Potato Tubers

Abstract Fungi of the genus Fusarium cause dry rot, a potato disease which develops during long-term storage of tubers. The disease-inducing capabilities differ among Fusarium spp., but may also vary within species universally considered main dry rot agents. Identification of Fusarium spp. present on diseased tubers in a surveyed area can help minimize crop losses and mycotoxin contamination by, for example, applying proper fungicides or planning crop rotation. Here, we present a procedure of obtaining single spore colonies of Fusarium spp. from potato tubers infected by dry rot, their identification using molecular methods and ways of preservation.

Soft rot of potatoes caused by Bacillus amyloliquefaciens in Guangdong province, China

Potato tubers exhibiting symptoms of soft rot were observed in a field in Baiyun District, Guangzhou, Guangdong Province, China, in March 2016. Bacteria were isolated from the diseased potato tubers. Using morphological and molecular (16S rDNA and gyrB) characterization and pathogenicity tests, a representative isolate of the bacterium was identified as Bacillus amyloliquefaciens. Inoculating the isolate onto healthy potato tubers led to soft rot with the same symptoms as displayed in the field, which confirmed Bacillus amyloliquefaciens as the causal agent. Further testing of the bacterial isolate on other hosts showed that it could also cause soft rot on tomato, onion and pepper. To our knowledge, this is the first report of soft rot of potato tubers caused by Bacillus amyloliquefaciens in the field.

Effects of chlorine dioxide on morphology and ultrastructure of Fusarium sulphureum and its virulence to potato tubers

The inhibitory effect and its virulence of chlorine dioxide (ClO2) against dry rot of potato were investigated. Potatoes were treated by ClO2, then observed for indoor bioassay, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the morphology and ultrastructure of hyphae, and evaluated the control efficiency of ClO2 on potato tuber (LK99) dry rot by F. sulphureum pre-treatment. The results showed that the pathogen of potato dry rot was sensitive to ClO2, the virulence of regression of y = 5.05 + 7.308x, EC50 and EC90 were 0.3490 and 0.6261 respectively, the treatment of ClO2 could significantly inhibit the spore germination and mycelium growth of F. sulphureum, which was in a concentration-dependent manner, SEM and TEM observed that the morphology and ultrastructure of F. sulphureum hyphae were regularly damaged by ClO2, in vivo experiment further indicated that ClO2 could effectively control the dry rot of potato tubers with F. sulphureum, and ClO2 at the concentration of 0.75 ug/mL could significantly reduce the incidence of potato tuber dry rot and lesion expansion rate. The study showed that ClO2 could greatly against the pathogen of F. sulphureum, which could provide a scientific theoretical basis for the safe and efficient application of ClO2 in the prevention and control of potato diseases after harvest. Keywords: potato, dry rot, chlorine dioxide, Fusarium sulphureum, virulence, morphology and ultrastructure DOI: 10.25165/j.ijabe.20171005.2403 Citation: Li M, Tian S L, Shen J, Wang X Z, Cheng J X, Li S Q, et al. Effects of chlorine dioxide on morphology and ultrastructure of Fusarium sulphureum and its virulence to potato tubers. Int J Agric & Biol Eng, 2017; 10(5): 242–250.

Application of an entomopathogenic fungus (Beauveria bassiana) increases potato nematodes reproduction and potato tubers damage caused by Ditylenchus destructor and D. dipsaci

Two greenhouse experiments were conducted to investigate the influence of Beauveria bassiana inoculated in the soil together with potato tuber rot nematode (Ditylenchus destructor) and stem and bulb nematode (Ditylenchus dipsaci). Data on nematode reproduction and consequently damage caused on potato tubers by these nematodes was investigated. In both experiments, the growing medium was inoculated with B. bassiana singly or in combination with D. destructor or D. dipsaci. B. bassiana alone did not negatively influence potato growth or tuber development. However, when B. bassiana was inoculated together with nematodes, higher nematode reproduction and tuber damage was observed at the end of the experiments. Tuber numbers and above ground fresh weight were not influenced by nematodes or a combination of B. bassiana and nematodes. Tuber weight was significantly reduced when nematodes were present together with B. bassiana. Although B. bassiana is an effective bio-control agent against some Meloidogyne spp., the application B. bassiana strain Naturalis in the presence of D. destructor and D. dipsaci might result in a detrimental interaction leading to higher nematode population densities and higher potato tuber damage.

Dryopteris crassirhizomaDryocrassinABBAfor Postharvest Control of the Potato Dry Rot PathogenFusarium solanivar. coeruleum

AbstractDryopteris crassirhizomadryocrassinABBAtreatment was tested for its effectiveness in controllingFusarium solanivar. coeruleumgrowthin vitroand for prevention of postharvest dry rot of potato tubers and slices. DryocrassinABBAstrongly inhibited mycelial growth, resulting in reductions in both mycelium dry weight and per cent spore germination ofF. solanivar.coeruleumat concentrations of 2.0, 0.5 and 0.1 mg/ml. Scanning electron microscopy (SEM) observations showed that treatment induced abnormal, tightly twisted morphological changes in hyphae. Moreover,in vivoexperiments demonstrated that dryocrassinABBAtreatment at 2 mg/mleffectively controlled dry rot of potato tubers inoculated with mycelial discs ofF. solanivar.coeruleum. After dryocrassinABBAtreatment, the content of soluble proteins, peroxidase (POD) and superoxide dismutase (SOD) activity increased, and malondialdehyde (MDA) content remained the stable situation. In addition, the expression level of plant lipid‐transfer proteins (LTPs) genes –StLTPa1,StLTPa7,StLTPb1andStLTPb3 –was upregulated. These results collectively demonstrate that dryocrassinABBAcan inhibit growth ofFusariumpathogens to induce disease resistance. On the other side, dryocrassinABBAmaybe induce potato defence responses.

First Report of Sclerotium rolfsii Causing Soft Rot of Potato Tubers in Spain

First Report of <i>Sclerotium rolfsii</i> Causing Soft Rot of Potato Tubers in Spain

Genetic Diversity of Pathogenic Fusarium semitectum Isolates from Potato Tubers, Using PCR-IGS-RFLP Markers

Fusarium semitectum is one of the important causal agents of dry rot of potato tubers in the world. In order to determine genetic variability among 41 isolates of F. semitectum, morphological and molecular studies were carried out. All F. semitectum isolates were recovered from infected potato tubers with dry rot symptoms collected from four provinces in Iran. According to macroscopic and microscopic characteristics, 41 isolates of F. semitectum were classified in two morphotypes (morphotypes I and II). All 41 isolates were evaluated for their pathogenicity on healthy potato tubers. Tuber rot symptoms were observed on the 21st day after inoculation of Fusarium isolates on the tubers tested. The measurement was done by comparing the depth and width of lesion expansion among the isolates. Molecular characterization through PCR-IGS-RFLP analysis by six restriction enzymes (AluI, BsuRI, Eco88I, MspI, TaqI and PstI) divided the 41 isolates of F. semitectum into two separated clusters that were in accordance with the morphological characterization.