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Background Spot blotch is a serious foliar disease of barley ( Hordeum vulgare L.) plants caused by Bipolaris sorokiniana, which is a hemibiotrophic ascomycete that has a global impact on productivity. Some Trichoderma spp. is a promising candidate as a biocontrol agent as well as a plant growth stimulant. Also, the application of nanomaterials in agriculture limits the use of harmful agrochemicals and helps improve the yield of different crops. The current study was carried out to evaluate the effectiveness of Trichoderma. cf . asperellum and the biosynthesized titanium dioxide nanoparticles (TiO 2 NPs) to manage the spot blotch disease of barley caused by B. sorokiniana and to assess the plant’s innate defense response. Results Aloe vera L. aqueous leaf extract was used to biosynthesize TiO 2 NPs by reducing TiCl 4 salt into TiO 2 NPs and the biosynthesized NPs were detected using SEM and TEM. It was confirmed that the NPs are anatase-crystalline phases and exist in sizes ranging from 10 to 25 nm. The T. cf. asperellum fungus was detected using morphological traits and rDNA ITS analysis. This fungus showed strong antagonistic activity against  B. sorokiniana (57.07%). Additionally, T. cf. asperellum cultures that were 5 days old demonstrated the best antagonistic activity against the pathogen in cell-free culture filtrate. Also, B. sorokiniana was unable to grow on PDA supplemented with 25 and 50 mg/L of TiO 2 NPs, and the diameter of the inhibitory zone increased with increasing TiO 2 NPs concentration. In an in vivo assay, barley plants treated with T. cf. asperellum  or TiO 2 NPs were used to evaluate their biocontrol efficiency against  B. sorokiniana,  in which  T. cf. asperellum  and TiO 2 NPs enhanced the growth of the plant without displaying disease symptoms. Furthermore, the physiological and biochemical parameters of barley plants treated with T. cf. asperellum or TiO 2 NPs in response to B. sorokiniana treatment were quantitively estimated. Hence,  T. cf. asperellum and TiO 2 NPs improve the plant’s tolerance and reduce the growth inhibitory effect of B. sorokiniana . Conclusion Subsequently, T. cf. asperellum and TiO 2 NPs were able to protect barley plants against B. sorokiniana via enhancement of chlorophyll content, improvement of plant health, and induction of the barley innate defense system. The present work emphasizes the major contribution of T. cf . asperellum and the biosynthesized TiO 2 NPs to the management of spot blotch disease in barley plants, and ultimately to the enhancement of barley plant quality and productivity. Key points • T. cf. asperellum showed strong antagonistic activity against  B. sorokiniana invitro . • Plant- based synthesis of TiO 2 NPs (10- 25 nm) using Aloe vera L. aqueous leaf extract. • B. sorokiniana triggers morphological and biochemical changes in barley plants, causing spot blotch disease. • T. cf. asperellum or green synthesized TiO 2 NPs positively increased the host plant's tolerance against this disease by inducing of osmolytes and antioxidant defense-related enzyme production.

Background S pot blotch caused by Bipolaris sorokiniana (Sacc.) Shoemaker significantly impedes global barley production by impacting grain, fodder yield, and malt quality. Host resistance presents a sustainable, cost-effective, and eco-friendly method for disease management. The extent of resistance and the number of resistant accessions are limited within barley genetic resources. Therefore, the present studies on the evaluation of the selected barley core collection consisting of 678 genotypes under the multi-environmental conditions have paramount importance. To identify stable resistance resources, the trial was conducted at Varanasi, India. This location is known as the hot spot of spot blotch. Results The analysis of variance (ANOVA) for determining varying levels of spot blotch resistance among the examined genotypes revealed a significant genotypic variation among the accessions against the disease based on the area under the disease progress curve (AUDPC). After correlating the disease severity with the elevated minimum temperatures and humidity levels, it was found to be higher during the first cropping season (2021–2022) with a mean AUDPC value of 852.89 ± 6.48 over the second cropping season (2022–2023) that showed a mean AUDPC of 761.10 ± 6.78. Average AUDPC scores across four test environments revealed that none of the evaluated genotypes showed a completely resistant reaction (AUDPC < 285) to spot blotch. Two genotypes (EC0667513-sel and EC0667512-sel) of six-row barley exhibited moderately resistant (MR) reaction (AUDPC < 355) under the natural field conditions; however, among these two, only EC0667513-sel was found to be MR during the validation under the artificial epiphytotic conditions. Further comparison of the performance and stability among these two MR genotypes through GGE biplot analysis indicated that EC0667512-sel was specifically adapted to certain environments, but was inconsistent overall. In contrast, EC0667513-sel indicated a good mean performance and higher stability across all environments. Conclusion The GGE biplot effectively analyzed genotype-environment interactions and identified optimal evaluation sites and stable resistant genotypes for spot blotch resistance. These findings provide valuable insights for future breeding programs focused on integrating resistance traits into new barley varieties.

Spot blotch caused by Bipolaris sorokiniana is a destructive disease of wheat worldwide. This study investigated the aggressiveness of B. sorokiniana isolates from different wheat-growing areas of Bolu province in Turkey on the cultivar Seri-82. Host susceptibility of 55 wheat cultivars was evaluated against the most aggressive isolate. Our results indicated that the cultivars Anafarta and Koç-2015 were the most resistant. A specific and sensitive qPCR assay was developed for detecting the pathogen in plant tissues and evaluating wheat plants with different resistance levels. Three primer sets, BsGAPDHF/BsGAPDHR, BsITSF/BsITSR, and BsSSUF/BsSSUR, were designed based on glyceraldehyde-3-phosphate dehydrogenase, internal transcribed spacers, and 18S rRNA loci of B. sorokiniana with detection limits of 1, 0.1, and 0.1 pg of pathogen DNA, respectively. The qPCR assay was highly sensitive and did not amplify DNA from the other closely related fungal species and host plants. The protocol differentiated wheat plants with varying degrees of resistance. The assay developed a useful tool for the quantification of the pathogen in the early stages of infection and may provide a significant contribution to a more efficient selection of wheat genotypes in breeding studies. In the present study, expression levels of PR proteins, phenylalanine ammonia-lyase, catalase, ascorbate peroxidase, and superoxide dismutase enzymes were upregulated in Anafarta (resistant) and Nenehatun (susceptible) cultivars at different post-infection time points, but more induced in the susceptible cultivar. The results showed considerable variation in the expression levels and timing of defense genes in both cultivars.

Net blotches caused by Pyrenophora teres are important foliar fungal diseases of barley and result in significant yield losses of up to 40%. The two types of net blotch, net-form net blotch and spot-form net blotch, are caused by P. teres f. teres (Ptt) and P. teres f. maculata (Ptm), respectively. This study is the first to use a cross between Ptt and Ptm to identify quantitative trait loci (QTL) associated with virulence and leaf symptoms. A genetic map consisting of 1,965 Diversity Arrays Technology (DArT) markers was constructed using 351 progenies of the Ptt/Ptm cross. Eight barley cultivars showing differential reactions to the parental isolates were used to phenotype the hybrid progeny isolates. Five QTL associated with virulence and four QTL associated with leaf symptoms were identified across five linkage groups. Phenotypic variation explained by these QTL ranged from 6 to 16%. Further phenotyping of selected progeny isolates on 12 more barley cultivars revealed that three progeny isolates are moderately to highly virulent across these cultivars. The results of this study suggest that accumulation of QTL in hybrid isolates can result in enhanced virulence.

It is important to investigate the possibility of pathogen transmission between cultivated and uncultivated hosts due to the role of the latter in pathogen evolution and the creation of new pathotypes which may break resistance genes of cultivated hosts. Wild hosts can also act as a pathogen reservoir offseason and cause pathogen survival. Spot form of net blotch (SFNB), caused by the fungus Pyrenophora teres f. maculata ( PTM ), is an important foliar disease of barley worldwide. In this study, 19 isolates from barley and Hordeum murinum were identified as P. teres based on ITS regions and gpd sequence and 17 of these isolates were identified as the sub-species PTM based on PCR assay. In order to evaluate the pathogenicity of PTM isolates obtained from H. murinum on barley as well barley PTM isolates on H. murinum , three barley isolates and two H. murinum isolates were inoculated on one H. murinum line and four barley cultivars including Local, Jolge, Zahak and Oksin, which were previously identified as sensitive, semi-sensitive, semi-resistant and resistant to PTM , respectively. The net blotch severity was scored based on a 1–9 scale. ANOVA showed that interaction between hosts and isolates was not different significantly (Fisher’s test, P = 0.05) which means that each isolate had the same pathogenic behavior on both barley and H. murinum . Therefore, it is possible to transfer pathogens from wild barley to barley as well as in the opposite direction and H. murinum can be considered a threat to barley because of its potential as a PTM reservoir between two growing seasons as well as creating new pathotypes.

Fungal plant diseases driven by weather factors are common in European wheat and barley crops. Among these, septoria tritici blotch (Zymoseptoria tritici), tan spot (Pyrenophora tritici-repentis), and stagonospora nodorum blotch (Parastagonospora nodorum) are common in the Nordic-Baltic region at variable incidence and severity both in spring and winter wheat fields. In spring barley, net blotch (Pyrenophora teres), scald (Rhynchosporium graminicola, syn. Rhynchosporium commune) and ramularia leaf spot (Ramularia collo-cygni) are common yield limiting foliar diseases. We analysed data from 449 field trials from 2007 to 2017 in wheat and barley crops in the Nordic-Baltic region and explored the differences in severity of leaf blotch diseases between countries and years, and the impact of the diseases on yield. In the experiments, septoria tritici blotch dominated in winter wheat in Denmark and southern Sweden; while in Lithuania, both septoria tritici blotch and tan spot were common. In spring wheat, stagonospora nodorum blotch dominated in Norway and tan spot in Finland. Net blotch and ramularia leaf blotch were the most severe barley diseases over large areas, while scald occurred more locally and had less yield impact in all countries. Leaf blotch diseases, with severity >50% at DC 73–77, caused an average yield loss of 1072 kg/ha in winter wheat and 1114 kg/ha in spring barley across all countries over 5 years. These data verify a large regional and yearly variation in disease severity, distribution and impact on yield, emphasizing the need to adapt fungicide applications to the actual need based on locally adapted risk assessment systems.

Wheat is a crop of historical significance, as it marks the turning point of human civilization 10,000 years ago with its domestication. Due to the rapid increase in population, wheat production needs to be increased by 50% by 2050 and this growth will be mainly based on yield increases, as there is strong competition for scarce productive arable land from other sectors. This increasing demand can be further achieved using sustainable approaches including integrated disease pest management, adaption to warmer climates, less use of water resources and increased frequency of abiotic stress tolerances. Out of 200 diseases of wheat, 50 cause economic losses and are widely distributed. Each year, about 20% of wheat is lost due to diseases. Some major wheat diseases are rusts, smut, tan spot, spot blotch, fusarium head blight, common root rot, septoria blotch, powdery mildew, blast, and several viral, nematode, and bacterial diseases. These diseases badly impact the yield and cause mortality of the plants. This review focuses on important diseases of the wheat present in the United States, with comprehensive information of causal organism, economic damage, symptoms and host range, favorable conditions, and disease management strategies. Furthermore, major genetic and breeding efforts to control and manage these diseases are discussed. A detailed description of all the QTLs, genes reported and cloned for these diseases are provided in this review. This study will be of utmost importance to wheat breeding programs throughout the world to breed for resistance under changing environmental conditions.

Apple trees face various challenges during cultivation. Apple leaves, as the key part of the apple tree for photosynthesis, occupy most of the area of the tree. Diseases of the leaves can hinder the healthy growth of trees and cause huge economic losses to fruit growers. The prerequisite for precise control of apple leaf diseases is the timely and accurate detection of different diseases on apple leaves. Traditional methods relying on manual detection have problems such as limited accuracy and slow speed. In this study, both the attention mechanism and the module containing the transformer encoder were innovatively introduced into YOLOV5, resulting in YOLOV5-CBAM-C3TR for apple leaf disease detection. The datasets used in this experiment were uniformly RGB images. To better evaluate the effectiveness of YOLOV5-CBAM-C3TR, the model was compared with different target detection models such as SSD, YOLOV3, YOLOV4, and YOLOV5. The results showed that YOLOV5-CBAM-C3TR achieved mAP@0.5, precision, and recall of 73.4%, 70.9%, and 69.5% for three apple leaf diseases including Alternaria blotch, Grey spot, and Rust. Compared with the original model YOLOV5, the mAP 0.5increased by 8.25% with a small change in the number of parameters. In addition, YOLOV5-CBAM-C3TR can achieve an average accuracy of 92.4% in detecting 208 randomly selected apple leaf disease samples. Notably, YOLOV5-CBAM-C3TR achieved 93.1% and 89.6% accuracy in detecting two very similar diseases including Alternaria Blotch and Grey Spot, respectively. The YOLOV5-CBAM-C3TR model proposed in this paper has been applied to the detection of apple leaf diseases for the first time, and also showed strong recognition ability in identifying similar diseases, which is expected to promote the further development of disease detection technology.

Wheat is among the ten top and most widely grown crops in the world. Several diseases cause losses in wheat production in different parts of the world. Bipolaris sorokiniana (teleomorph, Cochliobolus sativus ) is one of the wheat pathogens that can attack all wheat parts, including seeds, roots, shoots, and leaves. Black point, root rot, crown rot and spot blotch are the main diseases caused by B. sorokiniana in wheat. Seed infection by B. sorokiniana can result in black point disease, reducing seed quality and seed germination and is considered a main source of inoculum for diseases such as common root rot and spot blotch. Root rot and crown rot diseases, which result from soil-borne or seed-borne inoculum, can result in yield losses in wheat. Spot blotch disease affects wheat in different parts of the world and cause significant losses in grain yield. This review paper summarizes the latest findings on B. sorokiniana , with a specific emphasis on management using genetic, chemical, cultural, and biological control measures.

The fungal genus Alternaria is a pan-global pathogen of > 100 crops, and is associated with the globally expanding Alternaria leaf blotch in apple ( Malus x domestica Borkh.) which leads to severe leaf necrosis, premature defoliation, and large economic losses. Up to date, the epidemiology of many Alternaria species is still not resolved as they can be saprophytic, parasitic or shift between both lifestyles and are also classified as primary pathogen able to infect healthy tissue. We argue that Alternaria spp. does not act as primary pathogen, but only as a necrosis-dependent opportunist. We studied the infection biology of Alternaria spp. under controlled conditions and monitored disease prevalence in real orchards and validated our ideas by applying fungicide-free treatments in 3-years field experiments. Alternaria spp. isolates were not able to induce necroses in healthy tissue, but only when prior induced damages existed. Next, leaf-applied fertilizers, without fungicidal effect, reduced Alternaria-associated symptoms (− 72.7%, SE: ± 2.5%) with the same efficacy as fungicides. Finally, low leaf magnesium, sulphur, and manganese concentrations were consistently linked with Alternaria-associated leaf blotch. Fruit spot incidence correlated positively with leaf blotch, was also reduced by fertilizer treatments, and did not expand during storage unlike other fungus-mediated diseases. Our findings suggest that Alternaria spp. may be a consequence of leaf blotch rather than its primary cause, as it appears to colonize the physiologically induced leaf blotch. Taking into account existing observations that Alternaria infection is connected to weakened hosts, the distinction may appear slight, but is of great significance, as we can now (a) explain the mechanism of how different stresses result in colonization with Alternaria spp. and (b) substitute fungicides for a basic leaf fertilizer. Therefore, our findings can result in significant decreases in environmental costs due to reduced fungicide use, especially if the same mechanism applies to other crops.