The etiology and epidemiology of European Blackberry (Rubus anglocandicans) decline in South-West of Western Australia

European Blackberry (Rubus anglocandicans A. Newton) is one of the top 20 Weeds of National Significance in Australia. It is a major weed of conservation areas, particularly in wetter regions, and is also a major weed of forestry and agriculture. Rubus anglocandicans is the most abundant and widespread species of European blackberry in the south-west of Western Australia (WA). Herbicides and cultural control methods are generally ineffective, or require multiple applications; however, this weed is often located within inaccessible areas, which limits control options. Therefore, biological control has been identified as the main option for the control of blackberry in Australia. Biocontrol started in the 1980s, initially with the appearance a strain of the host-specific rust Phragmidium violaceum in Victoria. This, so called “illegal strain” and later the official strain of the rust were eventually spread to WA, but they failed to provide control. The blackberry species specifically targeted was R. anglocandicans – the main species in the Manjimup-Pemberton area and along the Warren and Donnelly Rivers in the south-west of Western Australia. New strains of the rust were released in 2004 and 2005. In some areas the levels of rust developed on blackberry was high, at least initially. While monitoring for rust control, the presence of blackberry decline was noticed. The extent of the disease, with noticeable changes to vegetation structure, from an impenetrable tangle of vegetation to a parklike setting of trees and grass, following the disappearance of dense blackberry infestations, has lead to it being called “blackberry decline”. More detailed examination of the decline sites suggested that the decline was not due to the inoculated rust, but possibly due to a root pathogen. Surveys between 2010 and 2012 led to the recovery of ten different Phytophthora, nine Pythium species and Cylindrocarpon species. The surveys also identified other abiotic and biotic factors such as landforms and grazing that appear to be associated with the decline of blackberry. The Phytophthora species isolated included a new species from Phytophthora clade 6 which was described as P. bilorbang as a part of this study. The other Phytophthora species included P. cinnamomi from decline-free sites, and P.amnicola, P. cryptogea, P. inundata, P. litoralis, P. multivora, P. taxon personii, P. thermophila, and a P. thermophila-amnicola hybrid from decline sites. Primocane under-bark inoculations and pot infestation trials in the glasshouse provided evidence of the pathogenicity of P. bilorbang and P. cryptogea to R. anglocandicans. In a dual combination trial to examine synergistic effects between Phytophthora species, disease severity increased by combining at least two to three species including P. amnicola, P. bilorbang, and P. cryptogea under a regime of regular waterlogging. In an in planta under-bark inoculation trial in the field to confirm the pathogenicity of Phytophthora species in the blackberry decline with and without application of phosphite, phosphite reduced the size of lesions caused by all Phytophthora species. Extensive ‘on-ground’ surveys showed the “decline” to extend along at least 64 km of riverbank, and at present is only known from the Warren and Donnelly River Catchments. In this project, the etiology and epidemiology of the decline distribution have been investigated and a conceptual model, a “blackberry decline spiral” is proposed to describe the key factors that are hypothesised to be involved in the decline phenomenon of R. anglocandicans. This model includes predisposing, inciting and contributing factors. It is assumed that predisposing or stress factors such as periodic flooding set the stage for inciting factors (e.g. lack of genetic potential in R. anglocandicans and grazing by animals). Whilst contributing factors (e.g. Phytophthora species as root pathogens and leaf rust) included in the blackberry decline spiral all have a role in this syndrome, the involvement of the hypothesized predisposing and inciting factors are also essential for the expansion of the decline. This thesis has shown blackberry decline to be a complex syndrome made up of a number of factors, most significant of which are periodic flooding and damage to the roots by at least two Phytophthora species, P. bilorbang and P. cryptogea

The possibility for improvement of flowering, corm properties, bioactive compounds, and antioxidant activity in saffron (Crocus sativus L.) by different nutritional regimes

Saffron as one of the most precious spices and medicinal plants, is highly valued for its bioactive compounds. Quantity and quality in spices and medicinal plants can be improved by the plant nutrition. In this field study the sole and integrated application of various fertilizers types and arbuscular-mycorrhizal fungus (AM), Glomus mosseae with respect to the flower-related traits, corm properties, quality, bioactive compounds and antioxidant activity of saffron at Kerman region, Iran was examined over a three years period. The fertilizer treatments comprised control (non-amended soil); 20 Mg ha −1 compost; 10 Mg ha −1 compost+ 8 Mg ha −1 biochar and chemical fertilizers. In each fertilizer treatment, planting bed was inoculated or non-inoculated with AM. The results showed that during the first flowering period (2015–16), neither AM nor fertilizer types affected flowering. Inoculation with AM particularly in the application of fertilizer treatments through positive effects on different corm properties during the vegetative growing seasons of 2015–16 and 2017–18, improved flower-related traits in the next flowering periods of 2016–17 and 2017–18. Picrocrocin and safranal content as well as total phenolic content and total flavonoid content in tepals were considerably enhanced by organic amendments and chemical fertilizers compared with the control. While the total phenolic content in stigmata was reduced by AM-inoculation, the total flavonoid content and antioxidant activity of stigmata and tepals were not significantly influenced. Principal Component Analysis clearly discriminated the integrated nutritional treatments from the sole ones based on flower-related traits and corm properties which were positively related with integrated treatments. Organic amendments were characterized by a higher total phenolic content and antioxidant activity in stigmata. Chemical fertilizers alone or in AM-inoculation associated with quality attributes and total flavonoid content in tepals. Research findings confirmed that the integrated application of mycorrhizal fungus, organic, and chemical fertilizers significantly influences the overall production of saffron. </p

Evaluation of Phoma sp. Biomass as an Endophytic Fungus for Synthesis of Extracellular Gold Nanoparticles with Antibacterial and Antifungal Properties

The aim of our study was to examine the different concentrations of AuNPs as a new antimicrobial substance to control the pathogenic activity. The extracellular synthesis of AuNPs performed by using Phoma sp. as an endophytic fungus. Endophytic fungus was isolated from vascular tissue of peach trees (Prunus persica) from Baft, located in Kerman province, Iran. The UltraViolet-Visible Spectroscopy (UV&ndash;Vis spectroscopy) and Fourier transform infrared spectroscopy provided the absorbance peak at 526 nm, while the X-ray diffraction and transmission electron microscopy images released the formation of spherical AuNPs with sizes in the range of 10&ndash;100 nm. The findings of inhibition zone test of Au nanoparticles (AuNPs) showed a desirable antifungal and antibacterial activity against phytopathogens including Rhizoctonia solani AG1-IA (AG1-IA has been identified as the dominant anastomosis group) and Xanthomonas oryzae pv. oryzae. The highest inhibition level against sclerotia formation was 93% for AuNPs at a concentration of 80 &mu;g/mL. Application of endophytic fungus biomass for synthesis of AuNPs is relatively inexpensive, single step and environmentally friendly. In vitro study of the antifungal activity of AuNPs at concentrations of 10, 20, 40 and 80 &mu;g/mL was conducted against rice fungal pathogen R. solani to reduce sclerotia formation. The experimental data revealed that the Inhibition rate (RH) for sclerotia formation was (15, 33, 74 and 93%), respectively, for their corresponding AuNPs concentrations (10, 20, 40 and 80 &mu;g/mL). Our findings obviously indicated that the RH strongly depend on AuNPs rates, and enhance upon an increase in AuNPs rates. The application of endophytic fungi biomass for green synthesis is our future goal

In vitro and in vivo antifungal properties of silver nanoparticles against Rhizoctonia solani, a common agent of rice sheath blight disease

Sheath blight disease in rice has caused major crop losses worldwide. Managing the causal agent of disease Rhizoctonia solani Kuhn is difficult because of its broad host range and formation of sclerotia which can survive in harsh environmental conditions; therefore developing innovative disease management methods without application of hazardous chemicals has been considered as the main concern to maintain sustainable agriculture. This presented research has revealed the negative impact of silver nanoparticles (SNPs) on R. solani and disease progress both in vitro and in vivo. The adverse effects of the SNPs on R. solaniare significantly dependent on the quantity of SNPs, sprayed at different concentrations in vitro. The highest inhibition level against sclerotia formation and mycelia growth are 92 and 85%, respectively, at a SNPs concentration of 50 ppm. In vivo glasshouse experiments also showed that SNPs at the same concentration favourably affects both the fresh and dry weight of rice plants with a remarkable suppressive effect on the lesion development in leaves

Evaluation of Phoma sp. Biomass as an Endophytic Fungus for Synthesis of Extracellular Gold Nanoparticles with Antibacterial and Antifungal Properties

The aim of our study was to examine the different concentrations of AuNPs as a new antimicrobial substance to control the pathogenic activity. The extracellular synthesis of AuNPs performed by using Phoma sp. as an endophytic fungus. Endophytic fungus was isolated from vascular tissue of peach trees (Prunus persica) from Baft, located in Kerman province, Iran. The UltraViolet-Visible Spectroscopy (UV–Vis spectroscopy) and Fourier transform infrared spectroscopy provided the absorbance peak at 526 nm, while the X-ray diffraction and transmission electron microscopy images released the formation of spherical AuNPs with sizes in the range of 10–100 nm. The findings of inhibition zone test of Au nanoparticles (AuNPs) showed a desirable antifungal and antibacterial activity against phytopathogens including Rhizoctonia solani AG1-IA (AG1-IA has been identified as the dominant anastomosis group) and Xanthomonas oryzae pv. oryzae. The highest inhibition level against sclerotia formation was 93% for AuNPs at a concentration of 80 µg/mL. Application of endophytic fungus biomass for synthesis of AuNPs is relatively inexpensive, single step and environmentally friendly. In vitro study of the antifungal activity of AuNPs at concentrations of 10, 20, 40 and 80 µg/mL was conducted against rice fungal pathogen R. solani to reduce sclerotia formation. The experimental data revealed that the Inhibition rate (RH) for sclerotia formation was (15, 33, 74 and 93%), respectively, for their corresponding AuNPs concentrations (10, 20, 40 and 80 µg/mL). Our findings obviously indicated that the RH strongly depend on AuNPs rates, and enhance upon an increase in AuNPs rates. The application of endophytic fungi biomass for green synthesis is our future goal. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Application of Biosynthesized Silver Nanoparticles from Oak Fruit Exudates against <i>Pectobacterium carotovorum</i> subsp. <i>carotovorum</i> Causing Postharvest Soft Rot Disease in Vegetables

The main goal of our study was to determine whether biosynthesized silver nanoparticles (SNPs) could be used as a novel antibacterial material in order to control soft rot in vegetables. Exudates from oak fruit were used in the green synthesis of SNPs. Postharvest soft rot disease in vegetables has resulted in significant crop losses all over the globe. Because managing Pectobacterium carotovorum subsp. carotovorum (Pcc), the causal agent of soft rot disease, is difficult due to its wide host range, developing innovative disease-management methods that do not involve the use of hazardous chemicals is a top priority for maintaining sustainable agriculture. The current research has found that silver nanoparticles (SNPs) have a detrimental effect on the progression of Pcc and soft rot disease in in vitro conditions. At SNPs’ sub-MIC, the greatest levels of inhibition against tissue maceration were 22, 19.8, 21.5, and 18.5 percent in potato, zucchini, carrot, and eggplant, respectively. SNP treatment of tubers and fruits had a noteworthy suppressive impact on soft rot disease symptoms as compared to controls. SNPs may be able to replace chemical pesticides in the management and prevention of soft rot disease in vegetables in postharvest settings, according to this study

Investigating the Potential of Streptomyces spp. in Suppression of Rhizoctonia solani (AG1-IA) Causing Rice Sheath Blight Disease in Northern Iran

A study was conducted in the Guilan Province of Iran, using a variety of Actinomycetes species isolated from the rice fields, with the intention of identifying useful biocontrol agents to lessen rice sheath blight disease. The antagonistic effects against the rice pathogen agent were also assessed both in vitro and in vivo. The antifungal abilities of more than 30 Actinomycetes isolates against the Rhizoctonia solani K&uuml;hn (AG1-IA) were used. The biocontrol abilities of the most active isolates were studied in a greenhouse. The size of the inhibition zone against pathogen development and the most potent antagonist Actinomycetes isolates were determined based on the dual culture screening test findings. The ability to create hydrolytic enzymes including amylase, chitinase, protease, and lipase were shown by hydrolytic enzyme assays on the putative antagonists. Antifungal activities of Streptomyces isolates against fungus mycelia were also studied using SEM since, compared to the control grown mycelia and mycelia adjacent to the inhibition zone in the plate, tests revealed an unusual and deformed structure; in our opinion, the chitinase secreted can destroy fungal mycelium. Chloroform test showed that its antifungal effect persists upon exposure to chloroform. All possible isolates belonged to the Streptomyces species, according to the 16S rDNA molecular analysis of the majority of active isolates. Comparing isolates, G had the highest impact in reducing sheath blight disease. The Iranian strain of the Streptomyces has antifungal capabilities, highlighting its potential as a viable biocontrol agent to be used in an Integrated Disease Management (IDM) program to control the rice sheath blight disease