scholarly journals Diploid Potato Germplasm with Resistance to Dickeya solani

2020 ◽  
Author(s):  
Renata Lebecka ◽  
Iwona Wasilewicz-Flis ◽  
Dariusz Mańkowski

AbstractPotato growers suffer losses due to potato soft rot and blackleg caused by pectinolytic bacteria of different species. These bacteria cause yield loss during cultivation and storage, and can be transmitted to the next generations through seed tubers. The prevalence of Pectobacterium atrosepticum has decreased over the last 20 years in Europe in favour of Dickeya solani and P. carotovorum subsp. brasiliense. Twenty-six diploid interspecific Solanum hybrids, previously selected for tuber resistance to P. atrosepticum, were screened for resistance to a highly aggressive D. solani strain in terms of tuber and blackleg reaction. The bacterial strain used for inoculation was characterised by a relatively high optimal growth temperature in vitro, ranging from 33 to 35 °C. Twenty-four diploid clones did not differ in terms of tuber reaction to inoculation with this strain of bacteria in comparison with the clone USA 249, which is the somatic hybrid of S. brevidens (+) S. tuberosum with proven resistance to Pectobacterium. Seventeen clones performed significantly better in terms of blackleg resistance than the resistant potato cultivar Glada. Eleven of the selected diploids produced unreduced gametes, which allows their use in improving the resistance of tetraploid potatoes to diseases caused by bacteria of both Pectobacterium and Dickeya.

Agronomy ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 46
Author(s):  
Cristina Mihaescu ◽  
Daniel Dunea ◽  
Adrian Gheorghe Bășa ◽  
Loredana Neagu Frasin

Phomopsis juglandina (Sacc.) Höhn., which is the conidial state of Diaporthe juglandina (Fuckel) Nitschke, and the main pathogen causing the dieback of branches and twigs of walnut was recently detected in many orchards from Romania. The symptomatological, morphological, ultrastructural, and cultural characteristics, as well as the pathogenicity of an isolate of this lignicolous fungus, were described and illustrated. The optimum periods for infection, under the conditions prevailing in Southern Romania, mainly occur in the spring (April) and autumn months (late September-beginning of October). Strong inverse correlations (p < 0.001) were found between potential evapotranspiration and lesion lengths on walnut branches in 2019. The pathogen forms two types of phialospores: alpha and beta; the role of beta phialospores is not well known in pathogenesis. In Vitro, the optimal growth temperature of mycelial hyphae was in the range of 22–26 °C, and the optimal pH is 4.4–7. This pathogen should be monitored continuously due to its potential for damaging infestations of intensive plantations.


2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
M. M. Rahman ◽  
A. A. Khan ◽  
M. E. Ali ◽  
I. H. Mian ◽  
A. M. Akanda ◽  
...  

Extracts from eleven different plant species such as jute (Corchorus capsularisL.), cheerota (Swertia chiraitaHam.), chatim (Alstonia scholarisL.), mander (Erythrina variegata), bael (Aegle marmelosL.), marigold (Tagetes erecta), onion (Allium cepa), garlic (Allium sativumL.), neem (Azadiracta indica), lime (Citrus aurantifolia), and turmeric (Curcuma longaL.) were tested for antibacterial activity against potato soft rot bacteria,E. carotovorasubsp.carotovora (Ecc)P-138, underin vitroand storage conditions. Previously,EccP-138 was identified as the most aggressive soft rot bacterium in Bangladeshi potatoes. Of the 11 different plant extracts, only extracts from dried jute leaves and cheerota significantly inhibited growth ofEccP-138in vitro. Finally, both plant extracts were tested to control the soft rot disease of potato tuber under storage conditions. In a 22-week storage condition, the treated potatoes were significantly more protected against the soft rot infection than those of untreated samples in terms of infection rate and weight loss. The jute leaf extracts showed more pronounced inhibitory effects onEcc-138 growth both inin vitroand storage experiments.


2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
M. M. Rahman ◽  
M. E. Ali ◽  
A. A. Khan ◽  
A. M. Akanda ◽  
Md. Kamal Uddin ◽  
...  

A total of 91 isolates of probable antagonistic bacteria of potato soft rot bacteriumErwinia carotovorasubsp.carotovora(Ecc) were extracted from rhizospheres and endophytes of various crop plants, different soil varieties, and atmospheres in the potato farming areas of Bangladesh. Antibacterial activity of the isolated probable antagonistic bacteria was testedin vitroagainst the previously identified most common and most virulent soft rot causing bacterial strain Ecc P-138. Only two isolates E-45 and E-65 significantly inhibited thein vitrogrowth of Ecc P-138. Physiological, biochemical, and carbon source utilization tests identified isolate E-65 as a member of the genusBacillusand the isolate E-45 asLactobacillussp. The stronger antagonistic activity against Ecc P-138 was found in E-65in vitroscreening and storage potatoes. E-65 reduced the soft rot infection to 22-week storage potatoes of different varieties by 32.5–62.5% in model experiment, demonstrating its strong potential to be used as an effective biological control agent for the major pectolytic bacteria Ecc. The highest (62.5%) antagonistic effect of E-65 was observed in the Granola and the lowest (32.7%) of that was found in the Cardinal varieties of the Bangladeshi potatoes. The findings suggest that isolate E-65 could be exploited as a biocontrol agent for potato tubers.


Processes ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 482 ◽  
Author(s):  
Nader A. Ashmawy ◽  
Said I. Behiry ◽  
Asma A. Al-Huqail ◽  
Hayssam M. Ali ◽  
Mohamed Z. M. Salem

Phenolic acids and natural extracts, as ecofriendly environmental agents, can be used as bio bactericides against the growth of plant pathogenic bacteria. In this study, isolation trails from infected potato tubers and stems that showed soft rot symptoms in fields revealed two soft rot bacterial isolates and were initially identified through morphological, physiological, and pathogenicity tests. The molecular characterization of these isolates via PCR, based on the 16S rRNA region, was carried out by an analysis of the DNA sequence via BLAST and Genbank, and showed that the soft rot bacterial isolates belong to Pectobacterium carotovorum subsp. carotovorum (PCC1) and Dickeya solani (Ds1). The in vitro results of the tested phenolic acids against the cultured bacterial isolates proved that concentrations of 800, 1600, and 3200 μg/mL were the most effective. Ferulic acid was the potent suppressive phenolic acid tested against the Ds1 isolate, with an inhibition zone ranging from 6.00 to 25.75 mm at different concentrations (25–3200 μg/mL), but had no effect until reaching a concentration of 100 μg/mL in the PCC1 isolate, followed by tannic acid, which ranged from 7.00 to 25.50 mm. On the other hand, tannic acid resulted in a significant decrease in the growth rate of the PCC1 isolate with a mean of 9.11 mm. Chlorogenic acid was not as effective as the rest of the phenolic acids compared with the control. The n-hexane oily extract (HeOE) from Bougainvillea spectabilis bark showed the highest activity against PCC1 and Ds1, with inhibition zone values of 12 and 12.33 mm, respectively, at a concentration of 4000 μg/mL; while the HeOE from Citharexylum spinosum wood showed less activity. In the GC/MS analysis, nonanal, an oily liquid compound, was found ata percentage of 38.28%, followed by cis-2-nonenal (9.75%), which are the main compounds in B. spectabilis bark HeOE, and 2-undecenal (22.39%), trans-2-decenal (18.74%), and oleic acid (10.85%) were found, which are the main compounds in C. spinosum wood HeOE. In conclusion, the phenolic acids and plant HeOEs seem to raise the resistance of potato plants, improving their defense mechanisms against soft rot bacterial pathogens.


2016 ◽  
Vol 30 (1) ◽  
pp. 198-206 ◽  
Author(s):  
Angela R. Post ◽  
David S. McCall ◽  
Shawn D. Askew

Silvery threadmoss naturally reproduces through spore and bulbil production, both of which have potential to be controlled prior to establishment. Studies have not evaluated effects of turf protection products on moss protonema or gametophyte growth from spores or bulbils; consequently, most moss is controlled POST on putting greens. Initial studies were performed to determine the optimal growth temperature for spores and bulbils in sterile culture. Protonemata from spores grew optimally at 29.5 C and gametophytes from bulbils grew optimally at 22.5 C. Three subsequent in vitro studies were conducted to evaluate effects of turf protection products on moss development from spores or bulbils in axenic culture at a constant 24 C. Carfentrazone, which effectively controls mature silvery threadmoss gametophytes POST, also reduced green cover of moss protonemata and gametophyte production from spores and bulbils. All combinations with carfentrazone reduced area under the progress curve (AUPC) for green cover of moss for both spores and bulbils by 80% or more by 3 wk after treatment. Sulfentrazone, oxyfluorfen, oxadiazon, saflufenacil, flumioxazin, and pyraflufen-ethyl reduced AUPC of moss equivalent to carfentrazone for both propagule types. The two fosetyl-Al products, phosphite, and mineral oil caused an increase in silvery threadmoss cover between 22 and 113% of the nontreated for spores; however, only methiozolin positively influenced AUPC (90.2%) compared to the nontreated for bulbils. Though silvery threadmoss is typically targeted POST on putting greens, there are products that can provide PRE control, including the industry standard of carfentrazone. These data suggest that differences may occur between turf protection products in their ability to suppress silvery threadmoss establishment from spores or bulbils.


1994 ◽  
Vol 72 (6) ◽  
pp. 808-817 ◽  
Author(s):  
Pierre DesRochers ◽  
G. B. Ouellette

An unknown fungus isolated from an elm branch and inhibitory against Ophiostoma ulmi in vitro is described as Phaeotheca dimorphospora sp.nov. This dematiaceous deuteromycete propagates by endoconidia released after exfoliation of chlamydospore outer wall, as in mother cells of the type species Phaeotheca fissurella. However, P. dimorphospora differs from the type species by producing hyaline secondary ameroconidia between the endoconidial masses. Other ameroconidia, similar to the secondary ameroconidia, are produced through the chlamydospore outer wall. The optimal growth temperature of P. dimorphospora is 23 °C, whereas it is 15.5 °C for the type species. On media containing a high dextrose concentration (30 g ∙ L−1), colonies of P. dimorphospora are gray and crustose and grow slowly, at least initially. Conversely, on media with a low dextrose concentration (5 or 10 g ∙ L−1) colonies have a faster growth rate and appear whitish or ivory and fluffy. Key words: Phaeotheca dimorphospora, diagnosis, inhibition, Ophiostoma ulmi, Dutch elm disease.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Tamilarasan Thangavel ◽  
Robert Steven Tegg ◽  
Calum Rae Wilson

Multiple disease resistance is an aim of many plant breeding programs. Previously, novel somatic cell selection was used to generate potato variants of “Russet Burbank” with resistance to common scab caused by infection with an actinomycete pathogen. Coexpression of resistance to powdery scab caused by a protozoan pathogen was subsequently shown. This study sought to define whether this resistance was effective against additional potato tuber diseases, black scurf, and tuber soft rot induced by fungal and bacterial pathogens. Pot trials andin vitroassays with multiple pathogenic strains identified significant resistance to both tuber diseases across the potato variants examined; the best clone A380 showed 51% and 65% reductions in disease severity to tuber soft rot and black scurf, respectively, when compared with the parent line. The resistance appeared to be tuber specific as no enhanced resistance was recorded in stolons or stem material when challengedRhizoctonia solanithat induces stolon pruning and stem canker. The work presented here suggests that morphological characteristics associated with tuber resistance may be the predominant change that has resulted from the somaclonal cell selection process, potentially underpinning the demonstrated broad spectrum of resistance to tuber invading pathogens.


2021 ◽  
Vol 9 (11) ◽  
pp. 2270
Author(s):  
Patrice de Werra ◽  
Christophe Debonneville ◽  
Isabelle Kellenberger ◽  
Brice Dupuis

Pectobacterium and Dickeya species are the causal agents of blackleg and soft rot diseases in potatoes. The main pathogenic species identified so far on potatoes are Dickeya dianthicola, Dickeya solani, Pectobacterium atrosepticum, Pectobacterium brasiliense, Pectobacterium carotovorum, and Pectobacterium parmentieri. Ten years ago, the most prevalent Soft Rot Pectobacteriaceae in Europe were the Dickeya species, P. atrosepticum and P. carotovorum, with some variations among countries. Since then, a drastic increase in the abundance of P. brasiliense has been observed in most European countries. This shift is difficult to explain without comparing the pathogenicity of all Dickeya and Pectobacterium species. The pathogenicity of all the above-mentioned bacterial species was assessed in field trials and in vitro tuber slice trials in Switzerland. Two isolates of each species were inoculated by soaking tubers of cv. Desiree in a suspension of 105 CFU/mL, before planting in the field. For all trials, the Dickeya species were the most virulent ones, but long-term strain surveys performed in Switzerland indicate that P. brasiliense is currently the most frequent species detected. Our results show that the pathogenicity of the species is not the main factor explaining the high prevalence of P. brasiliense and P. parmentieri in the Swiss potato fields.


1983 ◽  
Vol 3 (4) ◽  
pp. 693-698
Author(s):  
F Wunderlich ◽  
G Giese ◽  
H Falk

The in vitro export of ribosomal ribonucleoprotein (rRNP) from Tetrahymena nuclei was investigated at the optimal growth temperature of 28 degrees C and at the nonlethal temperature of 8 degrees C. At both temperatures, nuclei exported ribosomal precursor particles that revealed the same physical qualities of size, appearance in negative-staining electron microscopy, sedimentation coefficient, buoyant density, and rRNA pattern. Surprisingly, fewer rRNP particles were exported at 8 than at 28 degrees C, as was revealed by a lower saturation plateau in the export kinetics from nuclei prelabeled with [3H]uridine. Upon a temperature increase from 8 to 28 degrees C, additional rRNP particles were exported. We conclude that nuclei export only a defined portion of rRNP particles at a given temperature, although enough potentially transportable rRNP particles are present in nuclei. Obviously, the reactivity of at least one of the reactants involved directly or indirectly in rRNP export changes with temperature.


1983 ◽  
Vol 3 (4) ◽  
pp. 693-698 ◽  
Author(s):  
F Wunderlich ◽  
G Giese ◽  
H Falk

The in vitro export of ribosomal ribonucleoprotein (rRNP) from Tetrahymena nuclei was investigated at the optimal growth temperature of 28 degrees C and at the nonlethal temperature of 8 degrees C. At both temperatures, nuclei exported ribosomal precursor particles that revealed the same physical qualities of size, appearance in negative-staining electron microscopy, sedimentation coefficient, buoyant density, and rRNA pattern. Surprisingly, fewer rRNP particles were exported at 8 than at 28 degrees C, as was revealed by a lower saturation plateau in the export kinetics from nuclei prelabeled with [3H]uridine. Upon a temperature increase from 8 to 28 degrees C, additional rRNP particles were exported. We conclude that nuclei export only a defined portion of rRNP particles at a given temperature, although enough potentially transportable rRNP particles are present in nuclei. Obviously, the reactivity of at least one of the reactants involved directly or indirectly in rRNP export changes with temperature.


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