Search Results (18)

Apple (Malus domestica Borkh.) production is increasingly threatened by fungal diseases under conditions of intensive horticulture and ongoing climate change. In southeastern Kazakhstan, symptoms associated with Alternaria spp. have become more frequent in commercial orchards; however, molecularly confirmed data on the pathogen associated with these symptoms remain limited. This study aimed to identify, using multigene molecular phylogenetic analysis, an Alternaria isolate obtained from infected apple leaves and fruits, to confirm its pathogenicity experimentally, and to compare the susceptibility of apple cultivars to this pathogen. For molecular identification, nucleotide sequences of four genetic markers—the ITS region of rDNA, SSU, tef1-α, and RPB2—were obtained by PCR and sequencing. The sequences were compared with reference data from the GenBank database using BLASTn, and phylogenetic relationships were inferred using the maximum likelihood method based on a concatenated dataset of the four loci. The isolate KZ17 clustered within the A. alternata clade, with the broader node uniting this group with A. gossypina and A. longipes receiving a bootstrap value of 78%. A total of 20 fungal isolates were obtained from 112 symptomatic apple leaf and fruit samples. Among them, one representative isolate, KZ17, was selected for multilocus molecular identification and pathogenicity testing. The pathogenicity of isolate KZ17 was confirmed in inoculation experiments on apple microshoots under controlled conditions. Artificial inoculation of detached leaves and ripe fruits of 14 apple cultivars revealed significant cultivar-dependent differences in susceptibility. Lesion diameters ranged from 12.3 ± 0.20 to 19.2 ± 0.35 mm on detached leaves and from 15.0 ± 1.2 to 30.0 ± 2.4 mm on ripe fruits. The least susceptible cultivars were ‘Granny Smith’, ‘Zaman’, and ‘Maksat’, whereas ‘Voskhod’, ‘Saltanat’, and ‘Kamila’ showed the greatest susceptibility. These differences were statistically significant (p < 0.001). This study provides the first multigene-based confirmation of the association of A. alternata with apple leaf and fruit lesions in southeastern Kazakhstan and demonstrates cultivar-dependent differences in susceptibility to this pathogen. These findings contribute to improved pathogen diagnostics, germplasm screening for resistance, and the development of plant protection strategies for commercial apple orchards. Full article

Plant growth-promoting (PGP) bacteria are beneficial microbes that can help plants mitigate various biotic and abiotic stresses through different PGP functions. Flavins (FLs) are involved in flavoprotein-mediated reactions essential for plant metabolism and could act as PGP molecules. The aim of this study was to isolate and characterize potential FLs secreting bacteria from apple (Malus domestica [Suckow] Borkh) roots based on their fluorescence and to evaluate their PGP properties, including FLs secretion. A total of 26 bacteria with increased fluorescence in liquid culture were isolated from the apple roots. Based on 16S rRNA sequencing analysis, 11 genetically different strains mostly from Burkholderia and Rhizobia spp. were identified. All isolates secreted considerable amounts of riboflavin. In vitro plant assays showed that under nitrogen (N) limitation, inoculated alfalfa (Medicago sativa) plants yielded at least 25% more dry mass than non-inoculated plants, and inoculation with AK7 and FL112 enriched plant tissue N content compared to non-inoculated plants. This improved N acquisition was not linked to symbiotic N fixation. Additionally, the isolates exhibited some other PGP properties. However, no specific PGP functions were linked to improved plant N acquisition but could potentially be linked to the FLs secretion. For future investigation, the mechanisms underlying improved plant N uptake should be assessed to gain a more in-depth understanding. Full article

The objective of this study was to evaluate the impact of two nitrogen doses in combination with strong creeping fescue (Festuca rubra L. ssp. rubra Gaudin) and Chewing’s red fescue (Festuca rubra L. ssp. commutata Gaudin) used as living mulches on the weed community in an apple tree (Malus domestica Borkh.) orchard. The cover grasses were sown in the tree rows, and herbicide fallow served as the control. Grass living mulches effectively reduced the number and share of annual weed cover and limited the spread of perennial plants compared with herbicide fallow. Use of F. rubra L. subspecies did not favor the biodiversity of the orchard agroecosystem flora, due to the effective soil surface coverage by sod in the tree rows. Living mulch sod was characterized by lower variability in weed taxa compared with the abundant weed composition in the herbicide fallow, which also exhibited the highest number of weed taxa each year. Dominant species in the orchard across all treatments included Trifolium repens L. and Taraxacum spp. Doubling the nitrogen fertilization rate, while limiting the application area to the tree canopy, did not increase the perennial weed population in the living mulch sod. Both subspecies are useful as living mulch in a young apple orchard, but from the perspective of sod durability and weed control, strong creeping red fescue offers better prospects. Full article

The Manchurian fruit moth, Grapholita inopinata (Heinrich) (Lepidoptera: Tortricidae), is an important pest of fruit crops, particularly apples (Malus spp., Rosaceae), and is classified as a quarantine pest in many European countries and other world regions. Until recently, this species was known only in Northeastern China, Japan, and Russia (from Eastern Siberia and the Far East). To determine the westernmost distribution of G. inopinata and assess its abundance, we conducted nine-year pheromone monitoring across 13 administrative regions of Russia from 2014 to 2018 and 2021 to 2024. A total of 1866 traps were deployed, capturing 31,962 G. inopinata specimens in 1811 traps. The species was newly detected in eight regions—seven in Asian Russia and one in European Russia (Perm Krai). These findings doubled the moth’s known range on the Asian continent and extended its western boundary to 56° E in European Russia. Between 2021 and 2024, G. inopinata was generally found at low densities across the surveyed regions (≤10 males per trap per week), with the exception of Perm Krai, Omsk, and Novosibirsk Oblasts, where moderate abundance (up to 38 males per trap per week) was recorded. In contrast, from 2014 to 2018, moderate to high population densities (up to 94 males per trap per week), including mass occurrences (over 100 males per trap per week), were observed in Krasnoyarsk Krai, with an absolute peak capture of 303 males in one trap in June 2017. Notably, in 2015–2017, male flight activity in southern Krasnoyarsk Krai exhibited two distinct peaks: one in mid-to-late June and another from late July to mid-August, indicating the development of two generations. This is the first-ever record of a bivoltine seasonal cycle for G. inopinata in Siberia. These findings are critical for improving pest risk assessments and developing early detection strategies, supporting more effective monitoring and management approaches of this orchard pest. Full article

Extending the shelf life of perishable food, such as apples, and storing them in cold conditions and/or controlled atmospheres have been of great interest in the last decades. Apples are very valuable fruits with many health benefits, but during storage at ambient conditions, they ripen quickly and lose moisture, causing lower crispness or other negative effects, resulting in waste problems. There has been growing attention to protective edible coatings or active packaging films based on biopolymers and natural bioactive substances. Edible coatings and films allow for combination with functional ingredients or compounds, affecting the maintenance of the postharvest quality of fruits and vegetables. They also ensure the preservation of the sensory characteristics of food, and they can have antimicrobial or antioxidant properties. All these aspects play a significant role in the storage of apples, which can also help prevent waste, which is in line with the circular economy approach. The functionality of coatings and films is closely related to the type, content, and composition of active compounds, as well as their interaction with biopolymers. Active coatings with the addition of different functional compounds, such as plant extracts, phenolic acids, and nanoparticles, can be an alternative solution affecting the postharvest quality of apples during storage, maintaining the fruit’s stability, and thus minimising their waste. The most important issues related to the latest reports on improving the postharvest quality of apples using edible coatings incorporated with various active substances were evaluated. Agricultural conditions and factors that affect the postharvest quality of apples were described. The requirements for protective coatings for apples should be focused on low-cost materials, including waste-based resources, good miscibility, and compatibility of components. Those factors combined with the storage conditions may result in shelf life extension or retention of the postharvest quality of apples, regardless of the variety or cultivation techniques. Full article

For this article, we evaluated whether wounds would affect the pathogenicity and virulence of Colletotrichum sp. isolates on Musa spp. banana cultivars. We further assessed the potential of cross-colonization with other fruit species and investigated the molecular and phylogenetic characterization of the most virulent isolates. Firstly, we collected dwarf bananas showing anthracnose symptoms from commercial markets in the city of Gurupi, Tocantins State, Brazil, and isolated Colletotrichum sp. under controlled conditions prior to identification. The virulence was assessed on wounded and unwounded banana fruits, identifying the most virulent isolate by exposure tests on fruits of the “prata”, “maçã”, “marmelo”, and “terra” banana cultivars. We also subjected specimens of mango (Mangifera indica), papaya (Carica papaya), and apple (Malus domestica) fruits to the exposure tests. Our results indicated that pathogenicity varies with the isolate (with C2, C8, and C10 as the most virulent), fruit condition (wounded fruits are the most susceptible), and cultivars (terra, marmela, and maça are the most susceptible). All isolates were more virulent on wounded bananas, while those on unwounded ones showed lower virulence. Among the banana cultivars, “prata” fruits were the most susceptible, regardless of wounding. Additionally, Colletotrichum isolates from dwarf bananas were pathogenic to mango, papaya, and apple fruits. Furthermore, our results demonstrated that the most virulent isolates belong to the species C. musae. Collectively, our findings reinforce the relevance of minimizing post-harvest wounds on banana fruits and highlight the risks of cross-infection when storing bananas alongside other fruit species. Full article

Species of the genus Colletotrichum are among the most important plant pathogens globally, as they are capable of infecting many hosts—apple (Malus spp.) and other fruit and woody plant species—but also vegetable crops, cereals, legumes, and other annual and perennial herbaceous plants. The apple (Malus spp.) is attacked by various species from the genus Colletotrichum, whereby 27 different species from this genus have been described as the causative agents of apple bitter rot (ABR) and 15 as the cause of Glomerella leaf spot (GLS). These species generally belong to one of three species complexes: Colletotrichum acutatum, Colletotrichum gloeosporioides, and Colletotrichum boninense. The largest number of apple pathogens of the genus Colletotrichum belong to the species complex C. acutatum and C. gloeosporioides. However, further data on these species and the interactions between the species complexes of the genus Colletotrichum that cause these two apple diseases is needed for the development of effective control measures, thus ensuring successful and profitable apple cultivation. To contribute to this endeavor, a comprehensive review of the causative agents of ABR and GLS from the genus Colletotrichum is provided. In addition to presenting the species’ current names, distribution, economic significance, and the symptoms they cause in apple, their development cycle, epidemiology, and molecular detection strategies are described, with a particular emphasis on control measures. Full article

Apple canker disease, also named as apple Valsa canker, is one of the most destructive diseases for apples (Malus domestica Borkh.). Cytospora/Valsa spp. are the dominant causal agent of this disease, but many studies have revealed that fungi from some other genus can also cause typical apple canker symptoms. In this study, we performed fungal pathogen isolation from cankered ‘Fuji’ apple barks. Six representative morphologically different fungi (Strain 1–6) were further subjected to ITS sequencing and evolutionary analysis. Molecular identification results revealed that Strains 1–6 are Cytospora mali, Fusarium cf. solani, Alternaria alternata, C. mali, Diplodia seriata and F. proliferatum, respectively. All these fungi have been reported to be causal agents of apple diseases. By inoculating fungal plugs onto trunks of ‘Fuji’ apple trees, the pathogenicity of the six fungi were accessed. Only the inoculations of the two C. mali strains (Strain 1 and Strain 4) and the A. alternata strain (Strain 3) resulted in typical apple canker symptoms in trunks. It is worth noting that Strain 1 caused much more severe canker symptoms and higher pathogenicity incidence than the other two fungi. A. alternata has been identified as a pathogen causing diseases on apple fruits and leaves. By further assessing its pathogenicity on apple fruits and leaves, we verified that it can also cause typical fruit rot and leaf spot symptoms. To the best of our knowledge, this is the first report on apple canker disease caused by A. alternata in China. Our present study can provide a theoretical foundation for the prevention and control of apple canker disease. Full article

Sixty-seven apple tree accessions from the Centre for the Conservation of Agricultural Biodiversity of Tenerife (CCBAT) were molecularly characterised for the first time with 13 simple sequence repeats (SSRs). Additionally, previously studied genotypes from the Canary Islands (Tenerife, La Palma and Gran Canaria), Galicia, Asturias and commercial reference varieties were studied to identify possible synonymies and genetic structures, in order to improve the conservation of this genus in the germplasm bank. Thirty-three different genotypes were found in the new accessions analysed (51% clonality): sixteen of them (48%) exclusive to Tenerife, with no genetic coincidence with previous studies, making a total of thirty-three genotypes unique to Tenerife and sixty-five in the whole of the Canary Islands. The analysis of the population structure grouped the apple genotypes into two reconstructed panmictic populations (RPPs), one formed by local varieties or traditional ones (‘Peros’), RPP1, from all the regions studied, and the other formed by local and commercial varieties, RPP2. The RPP1 genotypes identified in Tenerife seem to show better adaptation to low chill, with a positive and significant correlation (0.388, p < 0.01), highlighting the importance of local varieties and the need for their conservation. This is the first study reporting significant correlation between genetic structure and chilling requirements. Full article

The tree fruit industry in Nova Scotia, Canada, is dominated by the apple (Malus domestica) sector. However, the sector is faced with numerous challenges, including apple replant disease (ARD), which is a well-known problem in areas with intensive apple cultivation. A study was performed using 16S rRNA/18S rRNA and 16S rRNA/ITS2 amplicon sequencing to assess soil- and root-associated microbiomes, respectively, from mature apple orchards and soil microbiomes alone from uncultivated soil. The results indicated significant (p < 0.05) differences in soil microbial community structure and composition between uncultivated soil and cultivated apple orchard soil. We identified an increase in the number of potential pathogens in the orchard soil compared to uncultivated soil. At the same time, we detected a significant (p < 0.05) increase in relative abundances of several potential plant-growth-promoting or biocontrol microorganisms and non-fungal eukaryotes capable of promoting the proliferation of bacterial biocontrol agents in orchard soils. Additionally, the apple roots accumulated several potential PGP bacteria from Proteobacteria and Actinobacteria phyla, while the relative abundances of fungal taxa with the potential to contribute to ARD, such as Nectriaceae and plant pathogenic Fusarium spp., were decreased in the apple root microbiome compared to the soil microbiome. The results suggest that the health of a mature apple tree can be ascribed to a complex interaction between potential pathogenic and plant growth-promoting microorganisms in the soil and on apple roots. Full article

Background: Traditional dyeing methods are practically forgotten in Poland. Józef Rostafiński included questions on the use of dyes in his ethnobotanical survey from 1883. Methods: 126 questionnaires contained information on dye plants. They were identified by the respondents using folk names or sometimes even Latin names. Folk names were analyzed by comparison with other literature. Several voucher specimens were also present. Results: 74 plant taxa were identified to genus or species level. The most commonly used were: onion (Allium cepa), brazilwood (Caesalpinia brasiliensis or Paubrasilia echinata), winter corn (mainly rye Secale cereale), black alder (Alnus glutinosa), safflower (Carthamus tinctorius), apple (Malus domestica), birch (Betula pendula), oak (Quercus robur), and violet flowering spring flowers (mainly Hepatica nobilis and Pulsatilla spp.). Conclusions: Most species are well known in the literature about plant dyeing, but the paper provides extra details on the picture of dyeing traditions in Eastern Europe. Full article

Apples are one of the most popular crops in the world, grown for fresh consumption, processing, and ornamental purposes. In the present study, the seeds of thirty crab apple (Malus spp.) genotypes were analyzed to evaluate the tocopherol composition and find a crop-specific profile. The mean proportion (%) of tocopherol (T) homologues (α, β, γ, and δ) was as follows: α-T (45.8%), β-T (21.8%), γ-T (24.3%), δ-T (8.1%) with a mean content of 22.41, 10.89, 12.35, and 4.08 mg/100 g dry weight, respectively. The coefficient of variation was higher in γ-T (0.748), δ-T (0.648) and β-T (0.540), and about two times lower for α-T (0.320). The total content of tocopherols varied much less in studied genotypes (coefficient of variation 0.164). α-T was the predominant tocopherol homologue in twenty-four genotypes (33.4–79.0%), while γ-T (36.4–64.9%) was the predominant in the remaining six studied genotypes. Principal component analysis identified six groups based on the tocopherol profile. Variety, purpose (ornamental vs. edible), and species appear to be associated with tocopherol profile. Most Malus sp., M. × prunifolia, and edible genotypes were located in two groups characterized by twice the content of α-T over β-T, and similar content of both (α-T and β-T), respectively. In both cases the sum of α-T and β-T constituted about 80% of total tocopherols. Significant correlations among tocopherol homologues were obtained: positive between α-T vs. β-T and γ-T vs. δ-T, and negative between α-T vs. γ-T, α-T vs. δ-T, and γ-T vs. β-T. These can be explained by the biosynthetic pathway of those lipophilic bioactive compounds. Full article

The synthesis of anthocyanin pigments in plants is known to be regulated by multiple mechanisms, including epigenetic regulation; however, the contribution of the RNA-directed DNA methylation (RdDM) pathway is not well understood. Here, we used bisulfite sequencing and Real Time (RT)-quantitative (q) PCR to analyze the methylation level of the promoter of constitutively photomorphogenic 1 (McCOP1) from Malus cv. spp, a gene involved in regulating anthocyanin biosynthesis. The CHH methylation level of the McCOP1 promoter was negatively correlated with McCOP1 RNA expression, and inhibiting DNA methylation caused decreased methylation of the McCOP1 promoter and asymmetric cytosine CHH methylation. We observed that the McCOP1 promoter was a direct target of the RdDM pathway argonaute RISC component 4 (McAGO4) protein, which bound to a McCOP1 promoter GGTTCGG site. Bimolecular fluorescence complementation (BIFC) analysis showed that RNA-directed DNA methylation (McRDM1) interacted with McAGO4 and another RdDM protein, domains rearranged methyltransferase 2 (McDRM2), to regulate the CHH methylation of the McCOP1 promoter. Detection of CHH methylation and COP1 gene expression in the Arabidopsis thalianaatago4, atdrm2 and atrdm1 mutants showed that RDM1 is the effector of the RdDM pathway. This was confirmed by silencing McRDM1 in crabapple leaves or apple fruit, which resulted in a decrease in McCOP1 CHH methylation and an increase in McCOP1 transcript levels, as well as in anthocyanin accumulation. In conclusion, these results show that the RdDM pathway is involved in regulating anthocyanin accumulation through CHH methylation of the McCOP1 promoter. Full article

Apple proliferation is an economically important disease and a threat for commercial apple cultivation. The causative pathogen, the bacterium ‘Candidatus Phytoplasma mali’, is mainly transmitted by Cacopsylla picta, a phloem-feeding insect that develops on the apple tree (Malus spp.). To investigate the feeding behavior of adults of the phytoplasma vector Cacopsylla picta in more detail, we used deep sequencing technology to identify plant-specific DNA ingested by the insect. Adult psyllids were collected in different apple orchards in the Trentino-South Tyrol region of northern Italy. DNA from the whole body of the insect was extracted and analyzed for the presence of plant DNA by performing PCR with two plant-specific primers that target the chloroplast regions trnH-psbA and rbcLa. DNA from 23 plant genera (trnH) and four plant families (rbcLa) of woody and herbaceous plant taxa was detected. Up to six and three plant genera and families, respectively, could be determined in single specimens. The results of this study contribute to a better understanding of the feeding behavior of adult Cacopsylla picta. Full article

Effector proteins play an important role in the virulence of plant pathogens such as phytoplasma, which are the causative agents of hundreds of different plant diseases. The plant hosts comprise economically relevant crops such as apples (Malus × domestica), which can be infected by ‘Candidatus Phytoplasma mali’ (P. mali), a highly genetically dynamic plant pathogen. As the result of the genetic and functional analyses in this study, a new putative P. mali effector protein was revealed. The so-called “Protein in Malus Expressed 2” (PME2), which is expressed in apples during P. mali infection but not in the insect vector, shows regional genetic differences. In a heterologous expression assay using Nicotiana benthamiana and Nicotiana occidentalis mesophyll protoplasts, translocation of both PME2 variants in the cell nucleus was observed. Overexpression of the effector protein affected cell integrity in Nicotiana spp. protoplasts, indicating a potential role of this protein in pathogenic virulence. Interestingly, the two genetic variants of PME2 differ regarding their potential to manipulate cell integrity. However, the exact function of PME2 during disease manifestation and symptom development remains to be further elucidated. Aside from the first description of the function of a novel effector of P. mali, the results of this study underline the necessity for a more comprehensive description and understanding of the genetic diversity of P. mali as an indispensable basis for a functional understanding of apple proliferation disease. Full article