Journal of Plant Diseases and Protection最新文献

Significant economic losses are inflicted by plant viruses, which pose a risk to sustainable agriculture. The proliferation of novel viral diseases is predominantly attributable to factors such as climate change, international trade, and the rapid evolutionary capabilities of viruses. Begomoviruses are a major group of plant-infecting viruses that pose an imminent threat to global agriculture by causing devastating viral diseases in many crop species. The transcriptional start sites (TSSs) of many plant viruses are typically found in the intergenic region (IR), which is the non-coding (NC) area between the viral genes. The promoters play a crucial role in initiating the transcription process by aiding in the recruitment of cellular transcription machinery. The TSSs are precise nucleotide sequences where RNA polymerase initiates the transcription process. The primary objective of this study was to determine the total number of TSSs for two devastating begomoviruses, family: Geminiviridae, Cotton leaf curl Multan virus (CLCuMuV) and Ageratum yellow vein mosaic virus (AYVMV), using the cap-snatching method in conjunction with one heterologous plant virus. These two begomoviruses, along with their infectious clones, were intentionally infected with selected heterologous plant virus in N. benthamiana plants. The identification of the 5′ ends of heterologous viral mRNA was accomplished by employing high-throughput sequencing to assess the capped RNA leaders (CRLs). The determination of the 5′ termini of suspected begomoviral mRNAs was achieved by aligning the collected CRLs of heterologous virus with the genome of each begomovirus, taking into account only those that were a perfect match with the begomoviral genome. In this study, the TSSs of both begomoviruses were identified via complementary approach. The utilization of high-throughput sequencing for both begomoviruses has facilitated the acquisition of millions of sequences. Comprehending the TSSs and promoter components of begomoviruses is crucial for understanding their ability to cause disease, their interactions with host organisms, and for developing effective methods to manage and control the diseases, they inflict on economically significant crop plants.

Field experiments were conducted in the summers of 2019 and 2020 to study the effects of soil solarization, biofumigants derived from cauliflower leaves and combinations of those treatments on population densities of soil pathogens Pythium ultimum, Fusarium oxysporum, Rhizoctonia solani, and Sclerotium rolfsii causing damping-off disease in major solanaceous crops. Nylon mesh bags containing mass culture of P. ultimum, F. oxysporum, R. solani, and S. rolfsii were buried underneath the soil at 5 and 10 cm depth. Soil solarization was performed over a 40-day period using thin transparent polythene sheet of 25 µm (100 gauge) thickness. Maximum soil temperatures recorded at depth of 5 cm were 41.8 °C in solarized soil, respectively; this temperature was 5.4 °C higher than in corresponding non-solarized plot. These nylon sieve bags containing culture of the different pathogens were retrieved after 15, 30 and 40 days of solarization and brought to the laboratory to find out the viability of the pathogens. Integration of soil solarization with cauliflower leaves as soil amendment for the period of 40 days at 5 cm soil depth was found most effective in reducing the viability of P. ultimum, F. oxysporum, R. solani, and S. rolfsii to 5.3, 2.6, 4.6, and 3.6% in comparison with 92.6, 77.3, 83.3, and 80.3 in control, respectively. With the increase in the duration of soil solarization from 15 to 40 days, the potential of the pathogens to cause the disease reduced significantly at 5 cm soil depth and incidence of the damping-off reduced from 63.3 to 16.6% in tomato; 66.6 to 20.0% in chilli and 70.0 to 23.3% in capsicum. Through this integrated approach, the viability of soil-borne pathogens can be minimized, thereby improving the overall plant health.

Peanut (Arachis hypogaea L.) holds significant commercial and dietary importance as a major source of edible oil and protein in Turkey. Stem, collar or root rot, caused by several fungal disease agent, are serious soil-borne diseases of peanut. Accurate and precise identification of the disease agent provides fundamental and precise information for integrated plant management. During the period from June to September 2021, symptoms consistent with collar rot disease, including dark-brown stem rot, chlorotic leaves, wilting, and eventual whole plant death, were observed on peanut plants cultivated in the different districts of Osmaniye Province of Turkey. The disease incidence ranged from 8.0 to 45.0% in the inspected fields with an average of 3.4% overall. Twenty-four single-spore representative isolates were obtained from surface-disinfected symptomatic tissues. Morphological characteristics of fungal mycelium, conidial and pycnidial structures on potato sucrose agar (PSA) and water agar (WA) closely resembled those described for Lasiodiplodia spp. All isolates caused typical collar rot symptoms upon artificial inoculation of peanut seedlings. Morphological identification of Lasiodiplodia spp. isolates was corroborated by MALDI-TOF and molecular analyses utilizing sequences from the internal transcribed spacer (ITS), β-tubulin 2 (tub2) and translation elongation factor-1 alpha (TEF1-α) loci. Phylogenetic analysis confirmed that the representative fungal isolates (MKUBK-B1 and MKUBK-K22) belong to Lasiodiplodia pseudotheobromae. To the best of our knowledge, this is the first report of L. pseudotheobromae infecting peanut plants in Turkey. This work is expected to contribute to previously limited knowledge regarding the host range, incidence and prevalence of L. pseudotheobromae as a soilborne pathogen of peanuts. Due to the potential destructiveness and broad host range of this pathogen, it is essential to develop new strategies to establish more reliable, environmentally sustainable, and cost-effective management approaches for this disease.

Dates maintain prime importance as sources of income and as symbols of cultural heritage in Saudi Arabia. Ephestia cautella (Walker) is one of the most important insects that attack stored dates. In an effort to safeguard small-scale producers, temperatures of 5 °C (representing typical house refrigerator temperatures), − 14 °C (representing in-house freezer temperatures), and − 25 °C (representing temperatures in small factory freezers) were applied to samples of dates previously infested with E. cautella larvae. Exposure periods of 1, 12, 48, 120, and 240 h were considered to assess the effectiveness of freezing temperatures against stored product insect pests. The temperature of − 25 °C proved to be the most effective, resulting in 100% mortality across all stages after just 1 h of exposure. At 5 °C, the pupal stage exhibited the highest tolerance, with only a mean mortality of 11% after 240 h of exposure. Conversely, at the same temperature, mean mortalities of 89% and 97% were recorded for eggs and larvae, respectively. However, when larvae were placed inside the dates, the mean mortality was only 65% after 240 h at 5 °C, complete larval mortality was achieved in 12 h at − 14 °C and 1 h at − 25 °C. This information can guide strategies for managing E. cautella in storage facilities with limited available resources.

The pathogens are reduced by volatile organic compounds (VOCs) generated by yeasts play an important role in controlling postharvest diseases. The yeast HXMG-1, which works effectively against the grey mould pathogen of grapes (Botrytis cinerea), was evaluated for its potential to generate volatile organic compounds as one of its modes of action. A double Petri dish assay was used to evaluate the effect of VOCs produced by HXGM-1 on mycelial and spore development of the target pathogens. Compared to the control, the VOCs produced by yeast HXMG-1 significantly reduced the growth of mycelium and spore germination of Botrytis cinerea. Specifically, the mycelial growth of Botrytis cinerea was completely restricted and the rate of spore germination of Botrytis cinerea was only 20.11% at a concentration of 1 × 10⁹ CFU/mL. It was also found that the VOCs could significantly inhibit mycelial growth with an inhibition of 82.46% at a concentration of 1 × 10⁸ CFU/mL. The VOCs caused the mycelium to grow curved, resulting in larger mycelial tips, fewer nuclei, and shorter mycelial septum spacing. In vivo tests, noninjure or injure grapes were artificially inoculated with the pathogen hyphal disc followed by biofumigation with VOCs produced by yeast HXMG-1, and the treatments (Wp2 and Wp3) significantly controlled pathogenic infection, confirming the results of in vitro tests. By molecular biological identification based on comparative sequence analysis of the 18S rDNA gene, the HXMG-1 strain was identified as Hanseniaspora uvarum. Through the creation of a phylogenetic tree, HXMG-1 was recognised as a member of the Ascomycota, Hemiascomycota, Yeasts, and Hanseniaspora sp. families. In conclusion, the yeast strain HXMG-1 created VOCs that significantly inhibited the development of Botrytis cinerea on grapes and is expected to be further developed and utilised. This study lays the foundation for the use of Hanseniaspora sp. for biological control of postharvest disease.

Cyclaneusma needle cast (CNC) is a needle disease which caused deterioration of vitality and reduction in the growth of pines. The disease is caused by the ascomycetous fungus Cyclaneusma minus, which has two well-described morphotypes; C. minus simile and C. minus verum. The distribution and host range of C. minus simile and verum was determined from needle samples and isolates collected throughout Slovakia from 2014 to 2020. Samples from 111 localities, 11 pine host species and 245 trees collected in different types of planting were analysed. It was found, that both morphotypes are present, but C. minus verum is predominantly responsible for CNC in urban and forest plantings in Slovakia. C. minus verum was positively detected in more than 88% of collected samples, whereas C. minus simile was only in four samples from three localities. Morphotype-specific primers were sufficiently sensitive even for new pine-host species. The host range of C. minus simile and C. minus verum was enriched worldwide. C. minus verum was observed in nine host species, whereas C. minus simile was identified only in one. Cyclaneusma niveum was also recorded and its presence was confirmed through DNA sequencing.

There is a high demand for natural agrochemicals to control postharvest phytopathogens in fruit. In this study, the Colletotrichum magnum strain was isolated from Maradol papaya fruits showing symptoms of anthracnose, identified based on its morphological characteristics and confirmed by an analysis of its 5.8S ribosomal DNA sequence. The antifungal activity of aqueous and ethanol extracts from Acacia pennatula, Acalypha gaumeri, Bonellia flammea, Calea urticifolia and Croton chichenensis was evaluated against Colletotrichum magnum by agar dilution bioassay at a concentration of 1 mg mL⁻¹ and recording mycelial growth inhibition (MGI), sporulation inhibition (SI) and spore germination inhibition (SGI) were recorded. The extracts that caused MGI of C. magnum by more than 30% were re-evaluated. It was concluded that the aqueous and ethanol extracts from B. flammea stem bark were the most effective in the MGI (91.53–94.49%), SI (99.32–99.65%), and SGI (91.65–100%) of C. magnum at a 3% (w/v) concentration. A serial dilution of the aqueous extract of B. flammea demonstrated that 2.35% and 3% (w/v) were highly effective against C. magnum in vitro, and both concentrations were randomly applied to postharvest Maradol papaya fruit by dip. The results found that both concentrations caused an anthracnose disease severity of 0.92–0.97% in papaya fruits, which was lower than the commercial fungicide Tecto 60®. The aqueous extract from B. flammea stem bark represents a promising opportunity for developing a natural biopesticide to effectively control anthracnose in papaya fruits induced by C. magnum.

Waitea circinata var. zeae, a pathogen with a relatively narrow host range, has recently been detected in cabbage and oilseed rape in Europe and worldwide. In this study, we developed specific conventional and real-time PCR protocols for direct detection of W. circinata var. zeae from mycelium and diseased plant tissue. The newly developed primer pair zeaefor1/zeaerew1, used in PCR protocols, specifically amplified only target isolates of W. circinata var. zeae when tested against isolates of 11 different binucleate and multinucleate anastomosis groups of Rhizoctonia spp. including AG-A, AG-G, AG-F, AG-U, AG-2-1, AG-2-2, AG-3, AG-4 HGI, AG-4 HGII, AG-4 HGIII, and AG-6 and common soil-borne pathogens. Total of nine previously published primer pairs designed for the detection of various Rhizoctonia spp. were also tested and did not amplify target isolates of W. circinata var. zeae. The detection limit of conventional and real-time PCR protocols was 10^–2 and 10^–5 (with starting concentration 9.5 ng/µl), respectively, and both methods are the first available tools for direct detection and identification of W. circinata var. zeae from mycelium and diseased oilseed rape seedlings. Both conventional and SYBR-Green-based real-time PCR protocols are cost-effective and provide a solid basis for further investigations of W. circinata var. zeae, particularly in relation to distribution, host range, and epidemiology.

Brazil is the largest coffee-producing nation in the world. Over 50% of the national production comes from the Minas Gerais state, with relevant contribution of the region covered by the Cerrado biome. Given the threat posed by root-knot nematodes (RKN, Meloidogyne spp.) to coffee production, we collected plant and soil samples from infested plantations across 16 counties and identified the species of this pathogen. Based on the female perineal patterns, male morphology, esterase phenotypes and SCAR markers, the species found were Meloidogyne exigua, Meloidogyne paranaensis, Meloidogyne incognita and Meloidogyne arenaria. The most prevalent species was M. exigua, occurring in 83.8% of the sampled sites, followed by M. paranaensis (19%) and M. incognita (4.9%). Mixed populations of RKN were observed in 7.7% of the sites, with the highest prevalence of M. exigua + M. paranaensis and M. paranaensis + M. incognita, followed by M. exigua + M. incognita. Meloidogyne arenaria was found in one site, in a mixed population with M. paranaensis + M. exigua. Strategies to prevent the spread of these nematodes to non-infested areas are highly recommended, particularly focusing on the most aggressive species such as M. paranaensis and M. incognita.

Camellia oleifera is an important edible oil woody plant in China. Anthracnose is a serious disease of C. oleifera, causing severe economic losses and posing a huge threat to the C. oleifera industry. The fungi Colletotrichum siamense is one of the main pathogens causing anthracnose of C. oleifera. In this study, antifungal activity of microorganisms isolated from garbage enzyme against C. siamense were investigated for the first time. 8 strains were isolated and purified from garbage enzyme. By morphological observation, gene sequence analysis, among the strains, 4 isolates were identified as Trichoderma harzianum and 4 isolates were identified as Bacillus subtilis. The result showed that 8 isolates displayed a relatively good potential on inhibiting the mycelial growth in C. siamense, but T. harzianum was more effective than B. subtilis as a biocontrol agent, with the best efficiency of 76.5%. In the vitro treatments, the combination of T. harzianum and B. subtilis were the most effective treatments in reducing the incidence and severity of anthracnose in C.oleifera, with the highest control efficiency of 77.56%. It can be concluded that T. harzianum and B. subtilis are promising biocontrol agents to manage anthracnose. These promising results provided valuable information on using garbage enzyme of wastes as a new source of antagonists to control fungi disease.