Antimicrobial activity of the edible mushroom Pleurotus eryngii (DC.) Quél grown in liquid medium

Edible mushrooms have a number of medicinal properties and this study aimed to investigate the antimicrobial activity of Pleurotus eryngii DPUA1816 in metabolic broths after being grown in submerged cultivation. Mycelial fragments of pure P. eryngii culture was inoculated in sweet potato culture medium and incubated at 150 rpm for 15 days at 25°C. Pleurotus eryngii was also cultivated for 18 days under the same conditions, the mycelial biomass was separated by filtration for quantification. The supernatant was used in the diffusion test in agar and performed against Escherichia coli CCCD-E005, Staphylococcus aureus CCCD-S009, Pseudomonas aeruginosa CCCD-P004, Candida albicans CCCD-CC001, Candida parapsilosis CCCD-CC004 and Candida tropicalis CCCD-CC002. The samples showed no inhibitory activity against bacteria, however they showed some activity against C. albicans (12.17 mm), C. parapsilosis (27.67 mm) and C. tropicalis (13.67 mm). After being cultivated for 18 days, P. eryngii was able to inhibit all yeasts after 12 days of culture, with an inhibition halo of 29.33 mm at 16 days against C. parapsilosis. This study demonstrates the antifungal potential filtered liquids from P. eryngii cultivated in purple-skinned sweet potato culture medium, which suggests the possibility of the use of this species by the pharmaceutical industry as a natural source of biological action.

Status of Paliga auratalis (Lepidoptera: Crambidae) as black potato pest and its control strategy using natural enemies: Paliga auratalis moth as black potato pest in Indonesia

Plectranthus rotundifolius is an edible tuber that widely distributed in Asia, covers India, Sri Lanka, Malaysia, and Indonesia. Plectranthus rotundifolius which commonly called as black potato in Indonesia is potential to be developed for national food diversification due to its high carbohydrates. However, one of challenges in black potato culture is the existence of moth pest infected the plants. This study was aimed to evaluate the status of Paliga auratalis moth as an insect pest in black potato plant and to develop the countermeasure strategy through its natural enemies. Observation and collection of P. auratalis and other potential insect pests was conducted in 12 black potato plantations located in five provinces of Java Island. The life cycle of P. auratalis was observed in the laboratory of Zoology Division, Research Center for Biology, Indonesian Institute of Science. Rearing of unhealthy P. auratalis larvae was also conducted to observe its natural enemies. We identified five species of moths infested black potato plants i.e.: Argyrograma sp., Pycnarmon cribat, Pleuroptya punctimarginalis, Rehimena diemenalis, and Paliga auratalis. Based on our observation, we confirmed that. P. auratalis is the main insect pest in Java Island with serious stack status. P. auratalis spend its lifecycle from eggs to adult between 25 – 32 days with the total eggs about 60-80 per female individual. We also identified two parasitic wasps as the natural enemies of P.auratalis i.e.: Aspanteles sp. and Cryptopimpla sp. which are potential to be a biological control agents of P. auratalis.

Use of growth inhibitor chlormequat chloride in potato culture in vitro

The publication presents data on the use of growth inhibitor chlormequat chloride in in vitro potato culture on varieties of different maturity groups: Meteor (early), Zekura (mid-early), and Northern Lights (mid-season). Five dosages of the investigational product were studied, ranging from 0.1125 to 1.8 g/l. It was found that in maximum doses of the product there was a strong inhibition of all growth processes in all varieties. The research results showed that the most optimal concentration of chlormequat chloride is 0.225 g per 1 liter of Murashige and Skoog medium. At this dose, on 30th day of cultivation, there was a decrease in the height of microplants from the control by 63.2-85.1%, in the root length - up to 15.0% and their number - up to 22.8% and an increase in the number of internodes by 6.5-22,0 % depending on the variety. The investigational product had an effect on formation of microtubers; in the Meteor variety, their largest number was 89.5% in the nutrient medium with a dose of 1.8 g/l, in the Zekura variety - 93.0% in the nutrient medium with a dose of 0.9 g/l. The new technique makes it possible to lengthen the periods between cuttings of test-tube plants by 2.3 times. This, in turn, reduces the cost of maintaining the in vitro collection material of potatoes in the summer-autumn period, and improves its quality, since each additional cutting cycle affects a more rapid degeneration of the variety. Also, microplants grown with growth inhibitor during subsequent relocation to a standard Murashige and Skoog medium did not show an aftereffect.

Dickeya dianthicola emerged from a potato culture area exhibiting a wide diversity of pectinolytic pathogens in northern Morocco

Background: Dickeya and Pectobacterium are pectinolytic pathogens that cause damage to many plants including major crops. Emergence of D. solani and re-emergence D. dianthicola were recently observed in potato fields in several continents. The purpose of this work was to describe the species diversity of Dickeya and Pectobacterium collected from potato fields in Northern Morocco, where Dickeya potato pathogens have not been isolated until recently. Results: Along three years, 119 pathogens belonging to Pectobacterium and Dickeya genera were isolated from three potato culture areas and characterized using selective PCR and gapA gene sequencing. Out of them, 19% belonged to P. versatile, 3% to P. carotovorum, 5% to P. polaris, 56% to P. brasiliense, while 17% to D. dianthicola. The taxonomic assignations were confirmed by draft genome analyses of representative isolates belonging to the collected species. D. dianthicola were isolated from a unique area where a wide species diversity of pectinolytic pathogens was also observed. In potato maceration assay, D. dianthicola isolates were more aggressive than Pectobacterium isolates, a feature that should alert stakeholders of a potential threat linked to the emergence of D. dianthicola in this country. By combining Oxford Nanopore Technologies (ONT) and Illumina technologies, the sequence of the complete genome of D. dianthicola LAR.16.03.LID was obtained. A unique circular chromosome of 4,976,211 bp codes for 4,223 predicted proteins. Comparison of the three complete genomes of D. dianthicola strains RNS049, ME23 and LAR.16.03.LID revealed a highly conserved synteny and the occurrence of strain-specific regions associated with the presence of mobile elements. Conclusion: By combining population sampling and genomics, this study highlighted the ecological context from which D. dianthicola emerged in Morocco. Furthermore, the first complete genome of a D. dianthicola strain isolated in Northern Morocco will constitute a reference genome for investigating the dynamics of the emerging D. dianthicola pathogens in this country.

Productivity and establishment of DRIS indexes for cultivation of potato cultivar Asterix tubers in a dystrophic Red Latosol

The potato culture has the highest relative demand for fertilizers per unit area, around 2.3 to 2.8 t ha-1. The objective of this study was to evaluate the productivity of a potato Asterix cultivar subjected to different doses of nitrogen, phosphorus, and potassium, and to establish the DRIS index according to productivity results. The experimental design was randomized blocks, with 5 rates and 4 replicates for each nutrient totalizing 20 plots per experiment. The rates of nutrients were: nitrogen (0, 70, 140, 210 and 240 Kg ha-1); phosphorus (0, 200, 400, 600 and 800 kg ha-1) and potassium (0, 150, 300, 450 and 600 kg ha-1). For leaf diagnosis by the DRIS index, 10 complete leaves of the third expanded trifoliate were collected. The DRIS standards calculations were based on populations of high productivity (or reference) and low productivity. Plants whose productivities were greater than 22 t ha-1 represented the groups of reference. It was concluded that productivity was not influenced by the P and K doses studied, with an increase in yield of tubers as a function of the N rates applied, up to the dose of 173 kg ha-1 of N. According to the DRIS index, it is possible to establish the order of limiting nutrients for failure in descending order in areas with high productivity Ca> Mn> P> S> Zn = Cu> K> N> B> Fe> Mg, and the order of limiting nutrients in areas of low productivity Ca> Cu> Mg> P> S> Mn> Zn> K> Fe = B> N. The results showed that productions above 22 t ha-1 need adjustments of the soil fertility managements.

WEEDS IN POTATO CULTURE AND THEIR OUTCOME IN SPREADING OF Alternaria spp.

The aim of this study was to determine whether the weeds accompanying potato crops can be a source of Alternaria spp. causing Alternaria leaf blight and to determine the genetic similarities of Alternaria alternata isolates infecting selected weeds: Chenopodium album, Cirsium arvense and tested potato cultivar. Three-year field experiment was conducted on the potato cultivar ‘Vineta N’. The isolates were classified into different species on the basis of macro- and microscopic features. In each year of the study, A. alternata dominated among the isolated fungi colonizing the leaves of potato plants and the selected weeds. The genetic similarities of A. alternata isolates was determined by the RAPD-PCR method. Tested genetic forms of A. alternata were closely related; only small differences in the pattern of the separated amplification products was evidenced. The dominance of A. alternata on the weeds accompanying potato crops suggests that if weed infestation is extensive, the pathogen is very likely to spread and its population to increase.