Leaf rust is one of the most devastating wheat diseases worldwide, to which many resistance genes have been ‎successfully introgressed ‎from wheat wild relatives. Though the Thinopyrum ‎ponticum-derived leaf rust resistance gene Lr19, is widely effective worldwide and previous studies ‎have shown its likely presence in Aegilops tauschii, no ‎thorough investigation has been conducted to confirm this. The present study aimed to ‎examine the presence of Lr19 in Ae. tauschii using a collection of molecular and bioinformatic analysis. Accordingly, the Thatcher line was used as susceptible, and a Thatcher+Lr19 (TcLr19) and Agatha were used as resistant lines. CDHLQ pathotyping coupled with DNA markers genotyping verified the presence of an Lr19 orthologue on Ae. tauschii 7DL (AtLr19). Sequencing of the GB marker products from Ae. tauschii and TcLr19 showed 99% homology in these fragments, confirming phenotyping and genotyping results. Both isolated segments were matched to a putative melatonin biosynthesis gene, namely O-methyltransferase-2 (OMT2) mapped to 7DL, with 100% identity. A hierarchical gene network was reconstructed using all identified putative genes within a genomic region containing 2.5 cM upstream and downstream of the OMT2 gene. Results indicated that several numbers of important biotic stress-responsive genes such as RPM1, RGA2, TRIUR3, BURP12, and myosin-11, were located downstream of melatonin as a master regulator molecule through the OMT2 node. To our knowledge, this is the first report of finding an orthologue for ‎Lr19 in Ae. tauschii, which provides insights into the possible regulatory route of LR19.

Leaf rust caused by Puccinia triticina Eriks. is the most prevalent wheat rust worldwide and occurs annually wherever wheat is grown. The most economical and environmentally friendly method to control this fungal disease is genetic resistance, which is achieved through deploying effective resistance genes. Tightly-linked molecular markers facilitate gene tagging and their deployment with other resistance genes which in turn contribute to durable leaf rust resistance. The leaf rust resistance gene Lr36 derived from Aegilops speltoides Taush and introgressed into hexaploid wheat by backcrossing, is located on chromosome 6BS. Despite detection of low frequencies of virulence for this gene, no molecular markers are available for marker-assisted selection in disease resistance breeding. Therefore, this research aimed at analysis of simple sequence repeat (SSR) markers linked with Lr36 in an F 2 population from a cross between the Lr36-carrying line (ER84018) and the susceptible cultivar; Boolani. Of 36 primer pairs on chromosome 6BS tested for polymorphism in parents and resistant and susceptible bulks, eight were polymorphic of which the markers Xgwm88 and Xcfd13 anked Lr36 by 3.8 and 5.2 cM, respectively. Evaluation of these markers on 35 genotypes from different backgrounds including few Australian wheat leaf rust differential sets, Iranian landraces and cultivars, and several cultivars and/or breeding lines from Switzerland and Afghanistan, con rmed that they can be used in selection for Lr36 in wheat breeding programs.

Wheat as a staple food source faces multiple biotic and abiotic stresses that pose major concerns for increasing its production (Mondal et al., 2016). In particular, the three rusts, that is leaf rust (Puccinia triticina, Pt), stripe rust (P. striiformis f. sp. tritici, Pst) and stem rust (P. graminis f. sp. tritici, Pgt), are the most devastating wheat diseases, which cause substantial yield losses worldwide (Huerta-

Yellow or stripe rust is one of the most important and destructive wheat diseases all over the world. The best strategy to control this disease is genetic resistance through combining several resistance genes which results in achieving long lasting resistance. Marker assisted selection has provided a suitable means towards this strategy. The aim of this study was to identify the race specific seedling genes Yr5 and Yr10 and the race nonspecific APR gene Yr29 in a selection of 40 Iranian genotypes using STS and SSR markers. Therefore, genomic DNA was extracted from these genotypes, the susceptible cultivar Avocet 'S' as negative control, and the genotypes with corresponding resistance gene (positive controls). PCR was performed using YrSTS7/8, Xpsp3000 and Xwmc44 markers for Yr5, Yr10 and Yr29, respectively. The results indicated the presence of Yr5 in only 6 genotypes. The presence of a 260 bps band also showed that Yr10 was present in 12 genotypes while Yr29 was present in 13 cultivars. As all these three genes are effective against yellow rust pathogen in Iran, it will be an advantage to transfer them to promising lines and develop durable resistance.

Leaf rust caused by Puccinia triticina Eriks. is the most prevalent wheat rust worldwide and occurs annually wherever wheat is grown. The most economical and environmentally friendly method to control this fungal disease is genetic resistance, which is achieved through deploying effective resistance genes. Tightly-linked molecular markers facilitate gene tagging and their deployment with other resistance genes which in turn contribute to durable leaf rust resistance.‎ The leaf rust resistance gene Lr36 derived from Aegilops speltoides Taush and introgressed into hexaploid wheat by backcrossing, is located on chromosome 6BS. Despite detection of low frequencies of virulence for this gene, no molecular markers are available for marker-assisted selection in disease resistance breeding. Therefore, this research aimed at analysis of simple sequence repeat (SSR) markers linked with Lr36 in an F2 population from a cross between the Lr36-carrying line (ER84018) and the susceptible cultivar; Boolani. Of 36 primer pairs on chromosome 6BS tested for polymorphism in parents and resistant and susceptible bulks, eight were polymorphic of which the markers Xgwm88 and Xcfd13 flanked Lr36 by 3.8 and 5.2 cM, respectively. Evaluation of these markers on 35 genotypes from different backgrounds including few Australian wheat leaf rust differential sets, Iranian landraces and cultivars, and several cultivars and/or breeding lines from Switzerland and Afghanistan, confirmed that they can be used in selection for Lr36 in wheat breeding programs.