Search Results (10)

Potatoes are a staple food crop consumed worldwide, with their significance extending from household kitchens to large-scale food processing industries. Their market value and quality are often compromised by various internal defects such as pythium, bruising, internal browning, hollow heart, gangrene, blackheart, internal sprouting, and dry rot. This study aimed to classify internal-based defects and investigate the quantification of internal defective areas in potatoes using visible and short-wavelength near-infrared spectroscopy. The acquisition of the spectral data of potato tubers was performed using a spectrometer with a wavelength range of 400–1100 nm. The classification of internal-based defects was performed using partial least squares discriminant analysis (PLS-DA), while the quantification of the internal defective area was based on partial least squares regression (PLSR). The PLS-DA double cross-validation accuracy for the distinction between non-defective and all internally defective potatoes was 90.78%. The double cross-validation classification accuracy achieved for pythium, bruising, and non-defective categories was 91.03%. The internal defective area model based on PLSR achieved a correlation coefficient of double cross-validation of 0.91 and a root mean square error of double cross-validation of 0.85 cm². This study makes a valuable contribution to advancing nondestructive techniques for evaluating internal defects in potatoes. Full article

Gastrodia elata, commonly known as Tian Ma, is a perennial mycoheterotrophic orchid. Qianyang Tian Ma (QTM), a geographical indication agricultural product from Hongjiang City, Hunan Province, China, is primarily characterized by the red variety, G. elata f. elata. A severe outbreak of tuber brown rot disease was documented in QTM during the harvesting season in Hunan. The fungal pathogen associated with the disease was isolated on potato saccharose agar (PSA) and identified through morphological and phylogenetic analyses. Pathogenicity tests were performed on healthy tubers of G. elata f. elata. The results showed that the representative isolate, named TMB, produced white hyphal colonies with a ring structure, broom-like phialides, partially curved ellipsoidal conidia, and orange–yellow spherical ascocarps on PSA. Phylogenetic analysis of the ITS, LSU, rpb2 and tub2 sequences using Bayesian and maximum-likelihood methods identified the isolate TMB as Clonostachys rosea, based on morphological and phylogenetic data. Pathogenicity tests revealed typical disease symptoms on healthy G. elata tubers 15 days post-inoculation with the isolate TMB. C. rosea is known to cause diseases in economically important crops, but there are no reports of its occurrence on G. elata f. elata in China. This study provides valuable insights into the occurrence, prevention, and control of brown rot disease in G. elata f. elata. Full article

Heat treatment is a widely applied technique in the preservation of fruits and vegetables, effectively addressing issues such as disease management, rot prevention, and browning. In this study, we investigated the impact of heat treatment at 35 °C for 24 h on the quality characteristics and disease resistance of two sweet potato varieties, P32/P (Ipomoea batatas (L.) Lam. cv ‘Pushu13’) and Xinxiang (Ipomoea batatas (L.) Lam. cv ‘Xinxiang’). The growth in vitro and reproduction of Rhizopus stolonifer were significantly inhibited at 35 °C. However, it resumed when returned to suitable growth conditions. The heat treatment (at 35 °C for 24 h) was found to mitigate nutrient loss during storage while enhancing the structural characteristics and free radical scavenging capacity of sweet potato. Additionally, it led to increased enzyme activities for APX, PPO, and POD, alongside decreased activities for Cx and PG, thereby enhancing the disease resistance of sweet potato against soft rot. As a result, the heat treatment provided a theoretical basis for the prevention of sweet potato soft rot and had guiding significance for improving the resistance against sweet potato soft rot. Full article

Light represents a powerful signal for the regulation of virulence in many microbial pathogens. Monilinia fructicola is the most virulent species causing brown rot in stone fruit crops. To understand the influence of light on M. fructicola, we measured the effect of white light and photoperiods on the colonial growth and sporulation of the model M. fructicola strain 38C on solid cultures. Searches in the M. fructicola 38C genome predicted a complete set of genes coding for photoreceptors possibly involved in the perception of all ranges of wavelengths. Since white light had an obvious negative effect on vegetative growth and the asexual development of M. fructicola 38C on potato dextrose agar, we studied how light influences photoresponse genes in M. fructicola during early peach infection and in liquid culture. The transcriptomes were analyzed in “Red Jim” nectarines infected by M. fructicola 38C and subjected to light pulses for 5 min and 14 h after 24 h of incubation in darkness. Specific light-induced genes were identified. Among these, we confirmed in samples from infected fruit or synthetic media that blue light photoreceptor vvd1 was among the highest expressed genes. An unknown gene, far1, coding for a small protein conserved in many families of Ascomycota phylum, was also highly induced by light. In contrast, a range of well-known photoreceptors displayed a low transcriptional response to light in M. fructicola from nectarines but not on the pathogen mycelium growing in liquid culture media for 6 days. Full article

The sulfur-containing salts, classified as food additives, sodium metabisulfite (SMBS), potassium metabisulfite (PMBS), aluminum sulfate (AlS), and aluminum potassium sulfate (AlPS), were evaluated for their activity against Monilinia fructicola, Rhizopus stolonifer, and Geotrichum candidum, the most economically important fungal pathogens causing postharvest disease of stone fruit. In in vitro tests with potato dextrose agar (PDA) Petri dishes amended with different concentrations of the salts (0, 10, 20, 30, 50, and 100 mM), SMBS and PMBS at all concentrations, AlS above 20 mM, and AlPS above 30 mM, completely inhibited the mycelial growth of the three fungi after incubation at 25 °C for up to 10 days. In in vivo primary screenings with artificially inoculated nectarines, aqueous solutions of the four salts reduced the incidence and severity of brown rot (BR) at concentrations of 10 and 50 mM, whereas only AlS and AlPS reduced Rhizopus rot (RR), and none of the salts was effective against sour rot (SR). Solutions at 100 mM were phytotoxic and injured the fruit peel. In small-scale trials, 1 min dip treatments at 20 °C in SMBS or PMBS at 10 mM significantly reduced the incidence and severity of BR after incubation at 20 °C for up to 8 days. Conversely, dips in AlS and AlPS reduced neither BR nor RR. Results highlight the potential of SMBS and PMBS as new nonpolluting tools for the integrated control of BR, but not RR and SR, on stone fruit. Full article

Fusarium dry rot on potato, caused by the fungal pathogen Fusarium solani, is characterized by an internal light to dark brown or black and usually dry rot of potato tubers. The disease progresses noticeably faster during the latter half of the storage season. Biological control of dry rot is an intriguing concept, but currently, no products are available commercially. It was found that the essential oil of a number Lamiaceae species, including oregano, have strong biocidal properties. A significant antifungal activity of Origanum vulgare ssp. hirtum essential oil against different phytopatogens in in vitro experiments has been demonstrated. In this study, the effect of oregano essential oil on potato tubers infected with Fusarium solani was evaluated. For this purpose, potato slices cut at thicknesses of 8–10 mm were inoculated with mycelium plugs of F. solani in the center of the slices. The oregano oil was tested using two approaches: contact and air impact. In the first approach, the essential oil was applied as an aqueous solution with a concentration range of 1–3 µg/mL on the potato tuber slices. In the second approach, the essential oil was placed in the Petri dishes with tuber slices in amounts from 5 to 50 µL without contact between them. A strong reduction in micellar growth on tuber tissue was observed at air impact during application of the essential oil in amounts of 25 μL and higher. The result showed that the Origanum vulgare ssp. hirtum essential oil shows antifungal activity against Fusarium solani and has the potential for application in storage rooms of potato tubers, especially during the last half of the storage season. Full article

The bacterial wilt pathogen, first known as Bacillus solanacearum, has undergone numerous taxonomic changes since its first description in 1896. The history and significance of this pathogen is covered in this review with an emphasis on the advances in technology that were used to support each reclassification that finally led to the current separation of Ralstonia solanacearum into three genomic species. Frequent name changes occurred as methodology transitioned from phenotypic, biochemical, and molecular studies, to genomics and functional genomics. The diversity, wide host range, and geographical distribution of the bacterial wilt pathogen resulted in its division into three species as genomic analyses elucidated phylogenetic relationships among strains. Current advances in phylogenetics and functional genomics now open new avenues for research into epidemiology and control of the devastating bacterial wilt disease. Full article

Lateral flow immunoassay (LFIA) is a convenient tool for rapid field-based control of various bacterial targets. However, for many applications, the detection limits obtained by LFIA are not sufficient. In this paper, we propose enlarging gold nanoparticles’ (GNPs) size to develop a sensitive lateral flow immunoassay to detect Ralstonia solanacearum. This bacterium is a quarantine organism that causes potato brown rot. We fabricated lateral flow test strips using gold nanoparticles (17.4 ± 1.0 nm) as a label and their conjugates with antibodies specific to R. solanacearum. We proposed a signal enhancement in the test strips’ test zone due to the tetrachloroauric (III) anion reduction on the GNP surface, and the increase in size of the gold nanoparticles on the test strips was approximately up to 100 nm, as confirmed by scanning electron microscopy. Overall, the gold enhancement approach decreased the detection limit of R. solanacearum by 33 times, to as low as 3 × 10⁴ cells∙mL^–1 in the potato tuber extract. The achieved detection limit allows the diagnosis of latent infection in potato tubers. The developed approach based on gold enhancement does not complicate analyses and requires only 3 min. The developed assay together with the sample preparation and gold enlargement requires 15 min. Thus, the developed approach is promising for the development of lateral flow test strips and their subsequent introduction into diagnostic practice. Full article

Brown rot fungus Fibroporia radiculosa (Peck) Parmasto grown in decayed wood and non-wood material, potato dextrose agar (PDA) media, deterred Reticulitermes speratus (Kolbe) feeding. Decayed wood and PDA media were extracted and tests were performed to assess termite feeding behavior towards the extracts. We found that the extract from PDA media also suppressed termite feeding, although it did not induce mortality. Using gas chromatography and mass spectrometry analysis, two bioactive compounds were detected from the decayed wood extract, and one was detected from the PDA extract. Based on National Institute of Science and Technology (USA) Mass Spectral library match and compound fragmentation, both of the compounds belong to the sesquiterpenes family. Full article

Potato is the most important root crop in Bangladesh. The field production is very much lower compared to other developed countries. Pests and diseases hampered the production due to the prevailing climatic condition, which favors the development in Bangladesh of specific diseases. Among them Brown rot (Ralstonia solanacearum) is the most alarming disease at present and previous time. The major areas of Bangladesh have faced many hampers on this disease. The potato growers and businessmen of Bangladesh are facing much problems on this disease especially in case of export to other countries as Russia, Malaysia, Singapore, Indonesia, Sri Lanka, Thailand, Hong Kong, Vietnam, Maldives, Turkey, Azerbaijan, Ethiopia and Nigeria. But during last year Russian Government banned import potatoes from Bangladesh. So, from these perspectives, this concept paper was studied to evaluate the most appropriate status of this disease caused by organisms and its best control strategies to impart better production thinking for Bangladeshi potato growers, exporters and other related personnels. Full article