Surveillance and monitoring the cereal rust diseases in Lebanon, Morocco, and Tunisia in 2022

Tracking the movement of the wheat rust pathogens and monitoring their pathogenic variabilities are the main pillars in successful breeding for durable rust resistance and disease management programs. Despite the severe drought conditions in wheat growing areas in CWANA in 2022, the rust surveillance was coordinated by the Regional Cereal Rust Research Center-Turkey in Lebanon, Morocco, and Tunisia, following the BGRI rust surveillance protocols. The national rust surveillance teams at the Lebanese Agricultural Research Institute, Institut National de la Recherche Agronomique (Morocco), and INSTITUT NATIONAL DES GRANDES CULTURES-TUNISIA (Tunisia) conducted the rust surveys in target countries. The GPS coordinates of survey sites, the status of rust diseases, and crop phenology were collected and shared with the online Global Cereal Rust Surveillance and Monitoring System (https://rusttracker.cimmyt.org) following the BGRI standard rust surveillance protocol (https://rusttracker.cimmyt.org/wp-content/uploads/2011/11/2013-Updated-BGRI-protocols-v2-web.pdf)

Identification of sources of resistance to scald (Rhynchosporium commune) and of related genomic regions using genome-wide association in a mapping panel of spring barley

Barley is an important crop worldwide known for its adaptation to harsh environments and used in multiple forms as feed, food and beverages. Its productivity is affected by major abiotic and biotic stresses. Scald caused by hemibiotrophic fungus Rhynchosporium commune is a major foliar disease in many parts of the world. Host plant resistance is targeted by breeders to efficiently control this disease. An association mapping panel of 316 spring barley genotypes (AM2017) was screened for seedling resistance in greenhouse against three R. commune isolates and for adult plant resistance in three field locations in Morocco. The phenotyping results showed different numbers of entries with resistant and moderately resistant reactions at both seedling and adult plant stages. The reactions differed between the isolates with the highest percentage of resistant genotypes observed for isolate SC-S611 (49.4%) and highest percentage of susceptible genotypes (73.8%) for isolate SC-1122. At adult plant stage, the highest percentage of scald resistant genotypes (64.5%) was observed at Rommani site compared to 56% at Guich site and only 28.8% at Marchouch site. Seven genotypes were resistant at the seedling and adult plant stages. Genome wide association study (GWAS) revealed 102 MTA (15 QTL) at the seedling stage, and 25 MTA (12 QTL) associated with scald resistance at the adult plant stage. In addition, the sequences of 92 out of 102 at SRT, and 24 out of 25 significant SNP markers at APR were located in genomic regions enriched with functional proteins involved in diverse cellular processes including disease resistance. These markers span over all chromosomes with the majority of SNPs located on 3H and 7H. This study has verified 18 QTL reported in previous studies. In addition, it was successful in identifying new sources of resistance and novel genomic regions which could help in enhancing scald resistance in barley breeding programs

STUDY REGARDIND THE ROLES OF HUMAN BETA-DEFENSIN 3 IN MONITORING OF PERI-IMPLANTITIS

Aim of the study Our study objective was to identify a possible association between the hBD-3 level from peri implant crevicular fluid and clinical status in post dental implant patients. Material and methods In this study we comprised 16 patients with dental implants that were examined after 7 and 21 days since dental implant installation and were included in our study based on probing depth (PD) and bleeding on probing (BOP) measurements as follows: 12 subjects with healthy implants and 4 patients with peri-implantitis. The periimplantar crevicular fluid samples were collected by using sterile paper points and the levels of hBD-3 were assayed by using an ELISA kit. Results Our study results show that there are highly significant statistically differences regarding the value of peri-implantar pocket depth between healthy and peri-implantitis patients evaluated after 7 and 21 days after insertion of dental implants (p<0.0001). Also, we obtained highly significant statistically differences regarding the hBD-3 values between healthy and peri-implantitis patients evaluated after 7 and 21 days after insertion of dental implants (p<0.0001). The study results show that there is a high inverse correlation between peri-implantar pocket depth and hBD-3 value in peri-implantitis patients evaluated after 7 days (r=-0.904) and a moderate positive correlation to the same patients evaluated after 21 days (r=0.400). Conclusions Within the limit of the study group, we can conclude that hBD-3 quantified in peri-implant crevicular fluid can be used as a biomarker in post-implant patient assessment and in peri-implantitis diagnosis

Genome-Wide Association Study of Leaf Rust Resistance at Seedling and Adult Plant Stages in a Global Barley Panel

Barley leaf rust caused by Puccinia hordei (Ph) is one of the major limiting biotic stresses of barley production worldwide and causes yield losses of up to 60%. A diversity panel of 316 barley genotypes (AM2017) composed of released cultivars, advanced breeding lines and landraces was screened for Ph resistance at the seedling stage using two isolates (SRT-SAT and SRT-MRC), while the adult plant stage resistance screening was conducted at the disease hotspot location of Sidi Allal Tazi (SAT) for the cropping seasons of 2017 and 2019. The phenotypic responses were combined with 36,793 single nucleotide polymorphism (SNP) markers in a genome-wide association study (GWAS) using the general linear model (GLM), mixed linear model (MLM), settlement of MLM under progressively exclusive relationship (SUPER), multiple-locus MLM (MLMM), fixed and random model circulating probability unification (FarmCPU), and Bayesian-information and linkage-disequilibrium iteratively nested keyway (BLINK) in GAPIT3, and MLM (K+Q), MLM (K+PCA), and GLM (Q) models in TASSEL to identify genomic regions linked to Ph resistance. Fourteen barley genotypes were resistant (R) at the seedling stage to both Ph isolates, SRT-SAT and SRT-MRC, and twelve genotypes were either resistant (R) or moderately resistant (MR) at the adult plant stage, whereas only one genotype was resistant at the seedling stage, and moderately resistant at the adult plant stage. The genome scan revealed 58 significant marker trait associations (MTA) among which 34 were associated with seedling resistance (SR) and 24 with adult plant resistance (APR). Common genomic regions conferring resistance to Ph were identified at both stages on chromosome 2H (106.53 cM and at 107.37 cM), and on chromosome 7H (126.7 cM). Among the 58 MTA identified, 26 loci had been reported in previous studies, while the remaining 32 loci were regarded as novel. Furthermore, the functional annotation of candidate genes (CGs) adjacent to 36 SNP markers with proteins involved in disease resistance further confirms that some of the SNP markers from our study could be associated with Ph resistance in barley. The resistant barley genotypes and some of the SNP markers from this study with high R2 and additive effects can be converted into high-throughput functional markers for accelerated selection and pyramiding of leaf rust resistance genes in North African barley germplasm