Elimination of Plant Pathogenic Bacteria by Solar Ultraviolet Radiation in Hydroponic Systems

Removing plant pathogens with the sun as a free, available, clean, and sustainable source of energy is interesting. However, there is no data for disinfecting major plant pathogenic bacteria such as Pseudomonas syringae and Clavibacter michiganensis subsp. michiganensis by solar ultraviolet radiation. To obtain the required time for killing these bacteria at different temperatures, a bacterial suspension of active growing cells (approximately 107 CFU mL-1) was prepared and subjected to heat inside a water bath. The minimum required time for killing both of the bacteria was achieved 420, 45, and 15 min at 50, 55, and 60 °C, respectively. To examine the effect of solar ultraviolet radiation, the bacteria suspensions inside a quartz tube were exposed to the sun on a horizontal surface at the constant temperature of 50 °C within the water bath (water depth: 0.1 m). Both of the bacteria were killed after one hour by receiving 95.481 kJ m-2 ultraviolet and 2.79315 MJ m-2 solar radiation doses. The synergy of heat and solar UV could considerably reduce the killing time of the bacteria (7 to 1 hours) at 50 °C. The recommended solar UV dose is 95.481 kJ m-2 for this condition

QTL mapping of partial resistance to basal stem rot in sunflower using recombinant inbred lines

Basal stem rot, caused by Sclerotinia sclerotiorum (Lib.) de Bary, is an important cause of yield loss in sunflower (Helianthus annuus L.). Quantitative trait loci (QTLs) implicated in partial resistance to basal stem rot disease was identified using the 116 recombinant inbred lines (RILs) from the cross between the sunflower parental lines PAC2 and RHA266. RILs and their parents were arranged in a completely randomized design with six replications and inoculated with a moderately aggressive isolate (SSU107) of S. sclerotiorum under controlled conditions. QTLs were mapped using a recently developed high-density single sequence repeat/ amplified fragment length polymorphism (SSR/AFLP) sunflower linkage map. Analysis of variance showed highly significant differences among the sunflower genotypes for susceptibility to basal stem rot. The frequency distribution of genotypes for susceptibility to disease showed continuous patterns, suggesting that resistance is controlled by a polygenic system. Transgressive segregation for resistance occurred in this cross. Composite interval mapping analysis revealed 7 QTLs for percentage necrotic area, localized on 7 linkage groups. The effects of QTLs were small to moderate indicating a polygenic control of the studied character. However, like any other quantitative trait, it is necessary to confirm the position of the QTLs and carry out fine-scale mapping before marker assisted selection (MAS). LG8 and LG16 are good candidates for further analysis to develop molecular markers for resistance to Sclerotinia disease

Morphological and phylogenetic analyses of Bipolaris species associated with Poales and Asparagales host plants in Iran

Bipolaris species exhibit various ecological roles, including plant pathogens, epiphytes, saprophytes, or endophytes, primarily associated with poaceous hosts, including cultivated cereals. Iran is known for its diverse climates and rich flora, which serve as a hotspot for fungal diversity. In this study, to determine the species diversity of Bipolaris associated with members of the Poales and Asparagales plant orders, samples with leaf and stem lesion symptoms were collected from these plants across various locations in Iran between 2010 and 2022. Based on the morphological characteristics and multi-locus phylogeny (ITS−rDNA, GAPDH, and TEF1), nine Bipolaris species were identified: Bipolaris avrinica sp. nov., Bipolaris azarbaijanica sp. nov., Bipolaris banihashemii sp. nov., Bipolaris hedjaroudei sp. nov., Bipolaris hemerocallidis sp. nov., Bipolaris iranica sp. nov., Bipolaris persica sp. nov., Bipolaris crotonis, and Bipolaris salkadehensis. B. crotonis represents a new record for Iran’s funga, while B. salkadehensis has been documented on several new hosts globally. The study provides detailed morphological descriptions and illustrations of all identified species, along with insights into their habitats, distributions, and phylogenetic relationships within the Bipolaris genus. This study also emphasizes the need for further research into fungal biodiversity in Iran and provides significant data on the distribution and host range of Bipolaris species

Fungal diversity notes 1611-1716: taxonomic and phylogenetic contributions on fungal genera and species emphasis in south China

243 p.This article is the 15th contribution in the Fungal Diversity Notes series, wherein 115 taxa from three phyla, nine classes, 28 orders, 48 families, and 64 genera are treated. Fungal taxa described and illustrated in the present study include a new family, five new genera, 61 new species, five new combinations, one synonym, one new variety and 31 records on new hosts or new geographical distributions. Ageratinicolaceae fam. nov. is introduced and accommodated in Pleosporales. The new genera introduced in this study are Ageratinicola, Kevinia, Pseudomultiseptospora (Parabambusicolaceae), Marasmiellomycena, and Vizzinia (Porotheleaceae). Newly described species are Abrothallus altoandinus, Ageratinicola kunmingensis, Allocryptovalsa aceris, Allophoma yuccae, Apiospora cannae, A. elliptica, A. pallidesporae, Boeremia wisteriae, Calycina papaeana, Clypeococcum lichenostigmoides, Coniochaeta riskali-shoyakubovii, Cryphonectria kunmingensis, Diaporthe angustiapiculata, D. campylandrae, D. longipapillata, Diatrypella guangdongense, Dothiorella franceschinii, Endocalyx phoenicis, Epicoccum terminosporum, Fulvifomes karaiensis, F. pannaensis, Ganoderma ghatensis, Hysterobrevium baoshanense, Inocybe avellaneorosea, I. lucida, Jahnula oblonga, Kevinia lignicola, Kirschsteiniothelia guangdongensis, Laboulbenia caprina, L. clavulata, L. cobiae, L. cosmodisci, L. nilotica, L. omalii, L. robusta, L. similis, L. stigmatophora, Laccaria rubriporus, Lasiodiplodia morindae, Lyophyllum agnijum, Marasmiellomycena pseudoomphaliiformis, Melomastia beihaiensis, Nemania guangdongensis, Nigrograna thailandica, Nigrospora ficuum, Oxydothis chinensis, O. yunnanensis, Petriella thailandica, Phaeoacremonium chinensis, Phialocephala chinensis, Phytophthora debattistii, Polyplosphaeria nigrospora, Pronectria loweniae, Seriascoma acutispora, Setoseptoria bambusae, Stictis anomianthi, Tarzetta tibetensis, Tarzetta urceolata, Tetraploa obpyriformis, Trichoglossum beninense, and Tricoderma pyrrosiae. We provide an emendation for Urnula ailaoshanensis Agaricus duplocingulatoides var. brevisporus introduced as a new variety based on morphology and phylogeny.Ministerio de Ciencia, Innovación y UniversidadesAgencia Estatal de InvestigaciónFEDE

Insecticidal activity and sublethal effects of Beauveria bassiana (Bals.-Criv.) Vuill. isolates and essential oils against Aphis gossypii Glover, 1877 (Hemiptera: Aphididae)

&lt;p&gt;The cotton aphid, &lt;em&gt;Aphis gossypii&lt;/em&gt; Glover, 1877, is a polyphagous species and one of the most important pests of cucumber crops in Iran. In this study, virulence of three &lt;em&gt;Beauveria bassiana &lt;/em&gt;(Bals.-Criv.) Vuill isolates, IRAN 108, IRAN 429C and LRC 137, as well as insecticidal activity of two essential oils extracted from &lt;em&gt;Matricaria chamomilla&lt;/em&gt; L. and &lt;em&gt;Cuminum cyminum &lt;/em&gt;L. were evaluated against adult stage of &lt;em&gt;A. gossypii &lt;/em&gt;under laboratory conditions. The data for life table were analyzed using the age-stage, two-sex life table theory. Results showed that all isolates were pathogenic on aphid, but their virulence was varied in different isolates. The lowest calculated LC&lt;sub&gt;50&lt;/sub&gt; was belonged to IRAN 429C (3.9 × 10&lt;sup&gt;4&lt;/sup&gt;conidia ml&lt;sup&gt;-1&lt;/sup&gt;). The lowest LT&lt;sub&gt;50&lt;/sub&gt; was obtained at concentration of 10&lt;sup&gt;8&lt;/sup&gt; and 10&lt;sup&gt;7&lt;/sup&gt; conidia ml&lt;sup&gt;-1&lt;/sup&gt; for IRAN 429C (2.9 and 3.55 days, respectively). &lt;em&gt;M. chamomilla&lt;/em&gt; essential oil had the lowest LC&lt;sub&gt;50&lt;/sub&gt; and LT&lt;sub&gt;50&lt;/sub&gt; values (19 µl l&lt;sup&gt;-1&lt;/sup&gt; air and 11.4 h), respectively. Longevity and population growth parameters, including the intrinsic rate of increase (&lt;em&gt;r&lt;sub&gt;m&lt;/sub&gt;&lt;/em&gt;), gross reproduction rate (&lt;em&gt;GRR&lt;/em&gt;), net reproductive rate (&lt;em&gt;R&lt;/em&gt;&lt;sub&gt;0&lt;/sub&gt;), generation time (&lt;em&gt;T&lt;/em&gt;) and finite rate of population increase (&lt;em&gt;λ&lt;/em&gt;), were affected negatively by both agents. According to the results obtained in this study, both entomopathogenic fungi and essential oils could be used as an alternative to chemical insecticides in aphid IPM programs.&lt;/p&gt;</jats:p

Apple crown and collar canker and necrosis caused by Cytospora balanejica sp. nov. in Iran

Abstract Apple is the most important fruit tree in West Azarbaijan province of Iran. In a survey of apple orchards, a disease with crown and collar canker and necrosis symptoms was observed in three young apple orchards in Urmia, affecting 15% and 1% of ‘Red Delicious’ and ‘Golden Delicious’ cultivars, respectively. A fungus with typical characteristics of the asexual morph of Cytospora was regularly isolated from the diseased tissues. Morphological characteristics and phylogenetic analyses inferred from the combined dataset of the ITS-rDNA, parts of LSU, tef1-α, rpb2, and act1 genes revealed that the isolates represent a new species of Cytospora, described herein as Cytospora balanejica sp. nov.. The pathogenicity of all isolates was confirmed on apple cv. ‘Red Delicious’ based on Koch’s postulates. Also, the reaction of 12 other apple cultivars was assessed against five selected isolates with the highest virulence. The results showed that except for cv. ‘Braeburn’, which did not produce any symptoms of the disease, the other 11 cultivars showed characteristic disease symptoms including sunken and discolored bark and wood. The mean length of the discolored area was different among the 11 so-called susceptible cultivars, hence cvs. ‘M4’ and ‘Golden Delicious’ showed the highest and the lowest lesion length, respectively. Moreover, the aggressiveness of the five tested isolates was different, and the isolates BA 2-4 and BA 3-1 had the highest and lowest aggressiveness, respectively. Based on our observations on the potential ability of the fungus to cause disease on young and actively growing apple trees, it will be a serious threat to apple cultivation and industry

Genetic structure of Sclerotinia sclerotiorum populations from sunflower and cabbage in West Azarbaijan province of Iran

AbstractSclerotinia sclerotiorum is one of the most destructive fungal pathogens infecting a wide array of plant species worldwide. Management of this pathogen relies on the coordinated use of fungicides and resistant host cultivars with other control measures, but the effectiveness of these methods requires knowledge of the genetic variability and structure of the fungal populations. To provide insight into the genetic diversity and structure of this pathogen in West Azarbaijan province of Iran, a total of 136 isolates were collected from symptomatic sunflower and cabbage plants within fields in three regions and analysed using inter-simple sequence repeat (ISSR) markers and intergenic spacer (IGS) region of the rRNA gene sequences. A total of 83 ISSR multilocus genotypes (MLGs) were identified, some of which were shared among at least two regional or host populations but in a low frequency. High genotypic diversity, low levels of clonal fraction, and random association of ISSR loci in a region indicated a low level of clonal reproduction, and possibly a high level of sexually recombining life cycle for the pathogen in the province. Marker analyses revealed that the pathogen was spatially homogeneous among fields, and thus similar control measures, such as the choice of resistant cultivars and fungicides, may effectively manage S. sclerotiorum within the region. Four IGS haplotypes (IGS1–IGS4) were detected within populations with IGS3 being the most prevalent haplotype. The low IGS haplotype diversity, the absence of spatial structure, and shared MLGs among populations may suggest a single introduction and subsequent dispersal of S. sclerotiorum within West Azarbaijan province.</jats:p