Resistant Accessions Research Articles

Genotyping-by-sequencing shows high genetic diversity in Corylus avellana germplasm resistant to eastern filbert blight

European hazelnut (Corylus avellana) is an anemophilous, dichogamous, self-incompatible tree nut species. It is native to a large portion of Europe, Turkey, and the Caucasus region, across which a wealth of plant genetic resources is present. The objective of this study was to evaluate the genetic diversity of a core set of C. avellana representing the world’s germplasm using genotyping-by-sequencing derived single nucleotide polymorphism (SNP) markers and to classify novel eastern filbert blight (EFB) resistant or tolerant accessions. Two-hundred-twenty-two accessions underwent next-generation sequencing (NGS) to generate SNP markers. From this, 1,250 SNP markers were used to construct a neighbor-joining (NJ) dendrogram and perform a STRUCTURE and discriminant analysis of principal coordinates (DAPC) analyses. In the dendrogram, five major groups were established, which generally corresponded to geographic origins of the plant materials studied. In STRUCTURE, support was found for groupings at (K) = 3, (K) = 6, and (K) = 10 populations, with the greatest Δ-(K) value occurring at (K) = 10. Although the three different analyses indicated slightly different solutions, the overall results were generally consistent from the standpoint of identifying similar accession groupings. For many of the accessions, recorded origins tended to correspond with their genetic grouping, although there was also evidence of intermixing and likely movement of plant materials. Interestingly, in all three analyses, a vast majority of the new accessions from the Republic of Georgia formed their own distinct group, highlighting this geographic region as a unique pool of C. avellana genetic resources. Overall, EFB resistant/tolerant accessions were placed across a wide range of genetic backgrounds. Thus, our results indicate EFB resistance/tolerance is present across a wide spectrum of C. avellana genetic resources, with the Georgian accessions representing a new and relatively unique germplasm pool that can be incorporated into hazelnut breeding programs.

Resistance of barley cultivars and accessions to pathotypes of the spot blotch causative agent

Background. The spot blotch disease caused by the hemibiotrophic fungus Bipolaris sorokiniana has become a serious problem for barley. Utilization of resistant or tolerant barley cultivars ensures sustainable diversity conservation and environmentfriendly crop production. Thus, supplying barley breeders with sources of resistance to harmful diseases is an urgent task. Materials and methods. A set of 100 barley accessions, earlier selected for different levels of resistance to B. sorokiniana, served as the material for this study. Eleven isolates of B. sorokiniana of various geographic origin, belonging to 4 pathotypes, were used for testing. The resistance of barley seedlings was assessed under controlled laboratory conditions, and that of adult plants under artificial infection pressure in the field. Responses to B. sorokiniana were scored using the 0–9 rating scale.Results and conclusions. Barley genotypes with race-specific resistance to the spot blotch causative agent were identified. The percentage of barley genotypes resistant to five isolates of B. sorokiniana pathotype 1 averaged 24.2%; two isolates of pathotype 3, 29.5%; three isolates of pathotype 7, 18.3%; and one isolate of pathotype 0, 37%. Barley accessions manifesting resistance in their seedlings, but susceptible in the phase of milk-wax ripeness, and vice versa, with seedling susceptibility and adult resistance, were identified. Six (6) barley genotypes showed seedling and adult resistance to pathotype 1, nine (9) to pathotype 3, and two (2) to pathotype 7. No barley accessions resistant to all isolates of the pathogen were found.

Comparative analysis of international and Malaysia approaches to the treatment of patients with chronic gastritis from the point of view of evidence-based medicine

Background: Chronic gastritis, often resulting from *Helicobacter pylori* infection, is a widespread gastrointestinal disorder. The condition requires evidence-based treatment approaches to ensure effective management and improved patient outcomes. This study conducts a comparative analysis of the treatment approaches for chronic gastritis in Malaysia and internationally, focusing on adherence to evidence-based medicine (EBM) practices. Understanding the similarities and differences in these approaches is critical for enhancing Malaysia's healthcare strategies. Methods and Materials: The study employed a systematic review of relevant literature sourced from global medical databases, including PubMed, Embase, and Cochrane Library. The review focused on therapeutic options, diagnostic standards, and evidence-based protocols for managing chronic gastritis, with emphasis on both international and Malaysian healthcare systems. Studies included in the review primarily focused on adult patients diagnosed with chronic gastritis and treated using evidence-based methodologies. Results: The analysis revealed significant parallels in the treatment protocols between Malaysia and international guidelines, particularly in the use of proton pump inhibitors (PPIs) and antibiotic regimens for *H. pylori* eradication. However, differences emerged in the implementation of advanced diagnostic tools, accessibility of healthcare services, and the influence of local antibiotic resistance patterns. While Malaysia follows global best practices, rural-urban healthcare disparities impact the consistency of treatment delivery and patient outcomes. Conclusion: Both international and Malaysian approaches to chronic gastritis prioritize evidence-based medicine. The findings suggest that Malaysia effectively adapts international guidelines to its local healthcare context, though improvements are needed in addressing healthcare accessibility and antibiotic resistance. Enhanced implementation of EBM practices, particularly in rural areas, and personalization of treatment based on resistance patterns, could further optimize patient outcomes in Malaysia.

“I Was in a Position to Enact Change:” College Athletes’ Use of Social Media for Racial and Social Justice

Recent shifts in societal activism have prompted an exploration of athlete activism, particularly within higher education, where social media has become a pivotal platform for social impact. This paper investigates Division I college athletes’ engagement in athlete activism through the lens of self-authorship and self-presentation on social media for racial and social justice. Existing research underscores the significance of social media in athlete activism, focusing on access barriers, advocacy efforts, and resistance against inequalities. Through an exploratory study, we investigate how college athletes’ processes of self-authorship and selfpresentation relate to social media activism. Our findings reveal three overarching themes: social media as an activist tool, empowerment, and a starting point for advocacy. The findings suggest avenues for college sports administrators to facilitate dialogue, comprehend the strategic utilization of social media in athlete activism, and acknowledge college athletes’ aspiration for increased involvement in effecting meaningful change within their communities. These insights contribute to a deeper understanding of college athletes’ contributions to social discourse and racial and social justice initiatives.

Genetic diversity of naked barley accessions from the VIR collection for resistance to powdery mildew in the North-West Region of the Russian Federation

BACKGROUND: Barley is an important grain crop characterized by adaptability to various growing conditions. In recent years close attention has been paid to groups of naked barley which compared to covered barley is more susceptible to the influence of pathogens, that decreases the yield and quality of grain. Powdery mildew is the most harmful diseases of barley (caused by the biotrophic fungus Blumeria graminis (DC.) Golovin ex Speer f. sp. hordei Marchal). The search for new promising sources of resistance to powdery mildew is necessary for barley breeding. AIM: The aim is studying the powdery mildew resistance of naked spring barley accessions from the world collection of VIR and identifying promising sources for economically valuable traits. MATERIALS AND METHODS: In field and laboratory conditions 271 of naked barley accessions of different ecological and geographical origin were studied for powdery mildew resistance and other economically valuable traits (lodging resistance, duration of the vegetative period, yield). The pathogen inoculum for laboratory work was represented by the north-western population of the pathogen. The resistance of barley samples was assessed in the field using the VIR point scale, in the laboratory using the E.B. Mains, S.M. Dietz point scale. The highly effective to powdery mildew resistance allele mlo11 was identified using PCR. RESULTS: The diversity of barley of different origins in resistance to powdery mildew is shown. 16 samples mainly from Europe, local forms from Ethiopia, Japan and India, were found to be resistant in field condition. According to the results of the assessment at the juvenile stage, 1 highly resistant sample k-31058 and 5 moderately resistant (k-20923, k-25801, k-27165, k-29911, k-30231) were identified. The naked forms k-20923 from Germany and k-29911 from Poland were resistant at all stages of plant development. The mlo11 allele was detected in the Arabische variety (k-20923) and heterogeneous pathogen resistance accessions k-20921, k-25793, k-27080, k-29440, k-29820. CONCLUSIONS: As a result of the work the sources of resistance to powdery mildew with a complex of economically valuable traits were identified, which can be involve in the breeding.

Physical and chemical characterization of wild tomato Solanum habrochaites accessions for resistance to the sweetpotato whitefly

Sweetpotato whitefly Bemisia tabaci is a significant worldwide insect pest affecting tomato production, causing direct damage during feeding and transmitting multiple plant viruses to this crop. Continuing research to improve integrated pest management (IPM) of sweetpotato whitefly is required to maintain profitable tomato production for growers. This study evaluated the resistance of eight wild tomato accessions of Solanum habrochaites and four commercial tomato cultivars of Solanum lycopersicum to sweetpotato whitefly infestation. Field experiments were conducted at the Wiregrass Research and Extension Center at Auburn University, where whitefly populations were reported in vegetable crops. Accessions and cultivars were evaluated for resistance to whiteflies through the ability to reduce the insect population, analysis of the presence of glandular trichomes, and the profile and quantification of terpenes of each tomato species. Results indicated significant variations in whitefly population dynamics among the wild tomato accessions and commercial tomato cultivars. Wild tomato accessions of S. habrochaites had higher numbers of glandular trichomes and distinct terpene profiles, particularly sesquiterpenes, known for their pest-repellent properties. Multivariate analysis identified three clusters based on terpene profiles and trichome types correlating with whitefly resistance. Accessions of S. habrochaites PI127826, PI134418, and G29258 had prominent results. They significantly reduced whitefly nymph development compared to cultivars of S. lycopersicum. The GC-MS analysis of leaflet extracts revealed that accessions of S. habrochaites had higher levels of sesquiterpenes, including α-zingiberene, β-caryophyllene, and α-humulene, with PI127826 uniquely producing Ar-curcumene and 9-hydroxy-zingiberene. Results highlight the potential of wild tomato accessions of S. habrochaites in breeding programs to enhance whitefly resistance in tomatoes, which can support a sustainable IPM program.

Comprehensive Herpesviruses Antiviral drug Resistance Mutation Database (CHARMD)

A comprehensive and accessible Herpesvirus drug resistance database was designed to serve as an international reference for diagnosis and clinical studies. This database available at https://www.unilim.fr/cnr-herpesvirus/outils/codexmv/ includes both resistance-related mutations and natural polymorphisms. Initially designed for human cytomegalovirus, it will be expanded to include herpes simplex and varicella-zoster viruses. Newly published mutations and new mutations reported by users or collaborating expert laboratories will be reviewed by an international committee of reference laboratories before inclusion in the database. Coupled with the Herpesvirus Sequence Analysis tool (HSA) mutation reports from NGS or Sanger sequences, it will be an open source for researchers in the field of Herpesviruses. We hope to fill this unmet need for the development and standardization of resistance genotyping.

Source/Drain Epitaxy for Nanosheet-Based CFET Devices

This work reports the progress in source/drain (S/D) epitaxy development for nanosheet-based monolithic complementary field effect transistors (mCFET). S/D processes which were set-up for bulk finFET devices can be easily transferred to mCFET devices. Owing to the complicated integration and small dimensions of the highly scaled structures however, more attention is required for the pre-epi cleaning of the exposed channel interfaces and for the additional defectivity that arises from the merging of individual epitaxial growth fronts. Low-temperature epi processes can be structurally integrated in mCFET devices, to further reduce the transistor access resistance components and comply with thermal budget limitations.

Wild mungbean resistance to the nematode Meloidogyne enterolobii involves the induction of phenylpropanoid metabolism and lignification.

Root-knot nematodes (Meloidogyne spp.) are plant parasites causing annual economic losses amounting to several billion US dollars worldwide. One of the most aggressive species is M. enterolobii, a growing threat to agriculture due to its broad host range and ability to overcome many known resistance genes. Mungbean, a nutritionally and economically valuable crop, is particularly vulnerable to nematodes and pathogens. However, research focusing on mungbean resistance to M. enterolobii is scarce, and the corresponding defense mechanisms are poorly understood. Here, we screened mungbean accessions and identified an accession strongly resistant to M. enterolobii. Transcriptome analysis revealed 2730 differentially expressed genes (DEGs) in this resistant accession (CPI106939) compared to 1777 in the susceptible accession (Crystal) 7 days after nematode inoculation. The gene ontology (GO) upregulated in CPI106939 with functions related to plant-pathogen interactions, plant hormone signaling, oxidative stress, and plant immunity. Plant defense-related genes (WRKY, PAL, MAPK, POD and PR) were also significantly induced in CPI106939. Metabolome analysis showed that four secondary metabolites related to phenylpropanoid metabolism and lignification were significantly enriched in CPI106939. The induced immune response and secondary metabolites may underpin the enhanced resistance to M. enterolobii, providing insight into the resistance mechanisms in accession CPI106939 as well as candidate genes controlling the interaction between mungbean and its nematode parasite. Our study therefore provides foundations for the breeding of new varieties with intrinsic M. enterolobii resistance.

Rmg10, a Novel Wheat Blast Resistance Gene Derived from Aegilops tauschii.

Wheat blast, caused by Pyricularia oryzae (syn. Magnaporthe oryzae) pathotype Triticum (MoT), is a devastating disease that can result in up to 100% yield loss in affected fields. To find new resistance genes against wheat blast, we screened 199 accessions of Aegilops tauschii, the D genome progenitor of common wheat (Triticum aestivum), by seedling inoculation assays with Brazilian MoT isolate Br48 and found 14 resistant accessions. A synthetic hexaploid wheat line (Ldn/KU-2097) derived from a cross between the T. turgidum 'Langdon' (Ldn) and resistant A. tauschii accession KU-2097 exhibited resistance in seedlings and spikes against Br48. In an F2 population derived from 'Chinese Spring' × Ldn/KU-2097, resistant and susceptible individuals segregated in a 3:1 ratio, suggesting that the resistance from KU-2097 is controlled by a single dominant gene. We designated this gene Rmg10. Genetic mapping using an F2:3 population from the same cross mapped the RMG10 locus to the short arm of chromosome 2D. Rmg10 was ineffective against Bangladesh isolates but effective against Brazilian isolates. Field tests in Bolivia showed increased spike resistance in a synthetic octaploid wheat line produced from a cross between common wheat cultivar 'Gladius' and KU-2097. These results suggest that Rmg10 would be beneficial in farmers' fields in South America.

Identification and confirmation of powdery mildew (Erysiphe polygoni) resistance in pea germplasm

Erysiphe polygoni DC, the causative agent of powdery mildew, poses a significant threat to pea crop, resulting in substantial yield and economic losses. To address this menace, an exploration of intrinsic resistance within pea germplasm becomes imperative for effective disease management. In our study, phenotyping of 1095 pea accessions, sourced from both indigenous and exotic origins, under natural epiphytotic conditions during Rabi 2021-22, revealed a prevailing susceptibility, with over 60 per cent disease severity in majority of accessions. Remarkably, only 22 accessions, including IC208327, IC220109, IC220378, IC258401, IC262762, IC262849, IC267140, IC267174, IC267727, IC274039, IC274040, IC310074, IC311066, IC345548, IC424898, IC552779, IC613133, IC629544, IC629687, NC57793, IC220193 and EC598669, exhibited resistance with a disease score of <1. Subsequent, pot screening of these 22 resistant accessions under artificial epiphytotic conditions during Rabi 2022-23 confirmed their resistance showing disease severity ranging from 5.83 - 17.50 per cent. Recognizing the pivotal role of resistant varieties in disease management, these identified accessions hold immense potential as resistant donors in crop improvement programs.. KEYWORDS :Germplasm, pea, powdery mildew, resistance

Improved Conductance Blockage Modeling of Cylindrical Nanopores, from 2D to Thick Membranes.

The ionic current blockage from a nanopore sensor is a fundamental metric for characterizing its dimensions and identifying molecules translocating through it. Yet, most analytical models predicting the conductance of a nanopore in both open and obstructed states remain inaccurate. Here, using an oblate spheroidal coordinate framework to study the electrical response of nanopore access regions, we reveal that the widely used model from Kowalczyk et al. significantly overestimates access region contributions when blocked by a cylindrical object, like DNA. To address this, we present an improved analytical model for the obstructed access resistance, which we establish as highly accurate through finite-element simulations, especially for ultrathin membranes and long narrow channels. Equipped with an improved nanopore conductance model, this work provides tools for more accurate calculation of the pore size and for the expected blockade from DNA, of high practical value for many biosensing applications.

Cryopreservation of zygotic embryos derived from BBTV resistant accessions of wild banana Musa acuminata

The wild banana species Musa acuminata encompasses numerous subspecies, some of which serve as ancestors of edible bananas. Preserving these subspecies is critical for food security, especially in regions where bananas are staple crops. While cryopreservation of M. acuminata subsp. burmanicoides zygotic embryos using air dehydration have shown high success rates, this method has not been effective for other subspecies. With at least 15 subspecies displaying various morphological traits, including seed morphology, alternative cryopreservation methods warrant exploration. In a recent study, successful cryopreservation using the droplet-vitrification method was achieved for mature zygotic embryos of accession of M. acuminata subspecies tomentosa, rutilifes, and malaccensis, all of which are resistant to the Banana bunchy top virus (BBTV). Using this approach, subjecting embryos to dehydration for 20 min in PVS2 solution and employing a regeneration medium comprising MS medium supplemented with benzyladenine and thidiazuron resulted in a success rate of 77.4 % (86 % survival rate × 90 % regrowth rate) for subsp. tomentosa and 50.4 % (70 % survival rate × 72 % regrowth rate) for subsp. malaccensis. Conversely, for subsp. rutilifes, dehydration for 10 min led to a success rate of 15.6 % (30 % survival rate × 52 % regrowth rate). Subspecies emerged as the primary factor influencing embryo regrowth, suggesting the need for protocol optimizations tailored to other subspecies. These findings highlight the potential of droplet-vitrification as a long-term preservation method for certain subspecies, while underscoring the necessity for further optimization for the other subspecies of M. acuminata.

Metabolome and Mycobiome of Aegilops tauschii Subspecies Differing in Susceptibility to Brown Rust and Powdery Mildew Are Diverse.

The present study demonstrated the differences in the seed metabolome and mycobiome of two Aegilops tauschii Coss accessions with different resistance to brown rust and powdery mildew. We hypothesized that the seeds of resistant accession k-1958 Ae. tauschii ssp. strangulata can contain a larger number of metabolites with antifungal activity compared with the seeds of susceptible Ae. tauschii ssp meyeri k-340, which will determine differences in the seed fungal community. Our study emphasizes the differences in the seed metabolome of the studied Ae. tauschii accessions. The resistant accession k-1958 had a higher content of glucose and organic acids, including pyruvic, salicylic and azelaic acid, as well as pipecolic acids, galactinol, glycerol and sitosterol. The seeds of Ae. tauschii-resistant accession k-1958 were found to contain more active substances with antifungal activity. The genera Cladosporium and Alternaria were dominant in the seed mycobiome of the resistant accession. The genera Alternaria, Blumeria and Cladosporium dominated in seed mycobiome of susceptible accession k-340. In the seed mycobiome of the resistant k-1958, a higher occurrence of saprotrophic micromycetes was found, and many of the micromycetes were biocontrol agents. It was concluded that differences in the seed metabolome of Ae. tauschii contributed to the determination of the differences in mycobiomes.

Fine mapping and identification of candidate genes associated with powdery mildew resistance in melon (Cucumis melo L.).

Powdery mildew (PM), a common disease of many major crop species, including melon (Cucumis melo L.), affects plant growth and fruit quality and seriously reduces production. Using a combined morphological and molecular approach, we attribute the PM pathogen that naturally occurs in melon to Podosphaera xanthii, and specifically to physiological race 1. An investigation into the genetic basis of PM resistance in melon using the resistant accession 'PI 164637' and susceptible counterpart 'HDZ' reveals dominant inheritance of PM resistance at the seedling stage, supported by F2 and backcross population segregation ratios. Adult plant assessments indicate a major gene with an additive effect for PM resistance. Bulk segregant analysis coupled with high-throughput sequencing identified a significant quantitative trait locus on chromosome 6 that is associated with PM resistance. Genetic mapping narrowed down the candidate region to 63.5kb using InDel molecular markers, harboring 12 candidate genes. The marker chr06_indel_5 047 127 demonstrated high accuracy in screening PM resistance in an F2 segregating population and 30 inbred lines as natural populations. Functional annotation and expression analysis of candidate genes revealed that MYB transcription factor MELO3C006700, GATA transcription factor MELO3C028829 and heparanase-like protein MELO3C006697 are promising candidate genes for PM resistance in melon. The genetic architecture underlying this resistance in melon offers valuable insights for breeding programs, and the identified markers, especially chr06_indel_5 047 127, may enable practical applications for marker-assisted selection in developing PM-resistant melon varieties.

Evaluation of Pepper (Capsicum spp.) Germplasm Collection for Bacterial Wilt (Ralstonia solanacearum) Resistance

This study was conducted to identify resistant pepper accessions against the destructive disease bacterial wilt (BW) caused by Ralstonia solanacearum. A total of 338 pepper (Capsicum species) germplasms collected from different countries and deposited in the National Agrobiodiversity Genebank, Rural Development Administration (RDA), Republic of Korea, were evaluated. The evaluated accessions comprise samples from five distinct species: Capsicum annuum (213), Capsicum baccatum (47), Capsicum chinense (45), Capsicum frutescens (31), and Capsicum chacoense (2). Disease severity scores were recorded over four consecutive weeks and showed an increase in severity from initial inoculation to the end of the evaluation period. A strong correlation was observed between week 1 and 2, as well as between week 3 and 4. Ten resistant pepper accessions were identified. All selected accessions consistently exhibited low disease scores ranging from 0 to 1 throughout the observation period. These accessions belong to C. chinense (2), C. annuum (6), C. chacoense (1), and C. frutescens (1). Accessions such as IT236738 (C. chinense) and IT283498 (C. chinense) were demonstrated to have high resistance, showing no symptoms over all four weeks. Other accessions belonging to C. annuum (IT247232 and IT236340) and C. chacoense (IT158713) maintained a disease score of 0 (no symptoms) for the first three consecutive weeks; however, they developed symptoms with a score of 1 in the fourth week. Other important characteristics of the resistant materials were evaluated, including carotenoids and fruit characteristics. These accessions have important traits beyond resistance to the destructive pepper disease. They will serve as promising resources for breeding resistant pepper varieties against BW to enhance productivity.

Comparative Analysis of Peroxidase and Catalase Isoenzymes via Native-PAGE Electrophoresis and SDS-PAGE Profiling of Leaf Proteins in Rice Varieties under Infection Stress

Rice (Oryza sativa L.) is a staple food for over half of the world's population. However, rice productivity is significantly hindered by various diseases, including sheath blight caused by Rhizoctonia solani. This study aims to evaluate the resistance of different rice varieties and wild rice accessions to sheath blight and to analyze the biochemical responses, specifically peroxidase and catalase activities, under infection stress. The results revealed that Kalanamak and Pusa Basmati were highly susceptible, with high disease indices and visual ratings. Conversely, wild rice accessions such as O. rufipogon and O. australiensis exhibited lower disease indices, indicating moderate resistance. Peroxidase activity varied significantly among the rice leaves, ranging from 148.83 to 182.44 mg/g fresh weight/min. Dhanya 748 showed the highest peroxidase activity, followed by O. australiensis and O. rufipogon. Native-PAGE electrophoresis of peroxidase isoenzymes demonstrated high-intensity bands in O. rufipogon, BPT 5204, and Swarna Sub-1, while minimal or no bands were observed in other genotypes, indicating varying levels of peroxidase activity. Catalase activity also showed significant variation, ranging from 138.18 to 152.14 mg/g fresh weight/min. BPT-5204 exhibited the highest catalase activity, followed by O. australiensis and Pusa Basmati. Isoenzyme analysis via Native-PAGE revealed high-intensity catalase bands in O. australiensis, Dhanya 748, NDR 118, and Pusa Basmati, while no bands were observed in O. rufipogon, CSR 13, Arize 6444, and Swarna Sub-1. SDS-PAGE analysis of leaf proteins showed variability in banding patterns. Non-infected leaves of Swarna Sub-1, Arize 6444, Kalanamak, and Pusa Basmati had minimal bands, while O. australiensis and Dhanya 748 showed maximum bands. Infected leaves of CSR 13, NDR 118, Arize 6444, Kalanamak, Dhanya 748, and Pusa Basmati had minimal bands, whereas O. australiensis exhibited maximum bands. Overall, the study highlights the potential of wild rice species in enhancing disease resistance and provides insights into the biochemical responses of rice varieties under pathogen stress.

Histological characterization of downy mildew infection in wild rocket (Diplotaxis tenuifolia)

AbstractWild rocket downy mildew (DM), caused by oomycete Hyaloperonospora sp., is a widely spread disease reducing crop production and quality. New productive wild rocket varieties resistant to DM are crucial to control disease and ensure high quality leaves. A histological characterization of Hyaloperonospora sp. infection was performed in 11 wild rocket (Diplotaxis tenuifolia) accessions with contrasting DM responses (R, resistant; PR, partially resistant; S, susceptible). Samples of infected cotyledons, first and second leaves of 14‐day‐old seedlings were collected at 3, 6, 9, 21 and 24 h post‐inoculation (hpi) and 7 days post‐inoculation (dpi) and stained for appressoria and haustoria observation and tissue necrosis evaluation. Occurrence of appressoria on host surfaces was higher in leaves compared with cotyledons but unrelated with DM resistance response. Haustoria growth in mycelium was delayed in R accessions from 3 hpi, and signs of cell hypersensitivity reaction were observed at 9 hpi. At 24 hpi, necrotic spots limited pathogen growth in resistant accessions, whilst mycelium invaded larger mesophyll areas and produced more haustoria in susceptible ones. At 7 dpi, sporulation was heavy in S, restricted to droplet deposition sites in PR, and did not occur in R hosts. A rapid response of R accessions resulted in slower mycelium growth and longer infection periods. These traits have important agronomic value and should be considered in germplasm selection for breeding programmes aimed at crop protection. A better understanding of the host response to DM infection will allow selection of more suitable wild rocket accessions in future breeding programmes.

Identification of Pathogen-Specific Novel Sources of Genetic Resistance Against Ascochyta Blight and Identification of Their Underlying Genetic Control.

Global chickpea production is restricted by Ascochyta blight caused by the necrotrophic fungi Ascochyta rabiei. Developing locally adapted disease-resistant cultivars is an economically and environmentally sustainable approach to combat this disease. However, the lack of genetic variability in cultivated chickpeas and breeder-friendly markers poses a significant challenge to Ascochyta blight-resistant breeding efforts in chickpeas. In this study, we screened the mini-core germplasm of Cicer reticulatum against a local pathotype of A. rabiei. A modified mini-dome screening approach resulted in the identification of five accessions showing a high level of resistance. The mean disease score of resistant accessions ranged between 1.75 ± 0.3 and 2.88 ± 0.4 compared to susceptible accessions, where the mean disease score ranged between 3.59 ± 0.62 and 8.86 ± 0.14. Genome-wide association study revealed a strong association on chromosome 5, explaining ∼58% of the phenotypic variance. The underlying region contained two candidate genes (Cr_14190.1_v2 and Cr_14189.1_v2), the characterization of which showed the presence of a DNA-binding domain (cl28899 and cd18793) in Cr_14190.1_v2 and its orthologs in C. arietinum, whereas Cr_14190.1_v2 carried an additional N-terminal domain (cl31759). qPCR expression analysis in resistant and susceptible accessions revealed ∼3- and ∼110-fold higher transcript abundance for Cr_14189.1 and Cr_14190.1, respectively.

Performance of cassava mosaic resistant accessions for tuber yield and starch content

Performance of cassava mosaic resistant accessions for tuber yield and starch content