Panjab University Chandigarh
Sterol 14?-Demethylase Cytochrome P450 (CYP51) protein involved in ergosterol biosynthesis pathways is a crucial target for efficient fungicidal compounds. However, the recognition mechanism and dynamic behavior of CYP51 in wheat leaf rust pathogen, Puccinia triticina is still obscure. Previously, a mutation at codon 134 (Y134F) was reported in five European isolates of P. triticina, the structural basis of this mutation remain unclear. To address this problem, CYP51 wild type protein and its variant proteins were successfully modeled using I-TASSER, an ab initio based structure prediction pipeline. To gain valuable insights into structure-function behavior for the binding wild-type and mutant-type proteins, individually generated protein models was subjected to 50ns molecular dynamics (MD) simulations run. Observably, this comparative protein-ligand interaction analysis and binding free energy results revealed that impact of mutation on the thermodynamics and conformational stability of the CYP51 protein is negligible. In present study, we carried out structure-based molecular docking and identified potent novel fungicidal compounds from four different databases and libraries. Consequently through MD simulation and thermodynamic integration, four novel compounds such as CoCoCo54211 (CoCoCo database),ZINC04089470(ZINC database), Allyl pyrocatechol 3,4 diacetate (Natural compound library) and 9-octadecenoic acid (Traditional Chinese Medicine database) has been predicted as potent fungicidal compound against CYP51 with XPGlidedocking score of -11.41, -12.52, -7.40 and -7.55 kcal/mol, respectively. These compounds were found to directly bond to heme group of CYP51, subsequently disturbing the stability and survival of fungus and can be used to control leaf rust in wheat.
Cereal Crops Research Institute Pirsabak Nowshera, Pakistan
Khilwat Afridi, Muhammad Ishaq, Irfan Shah, Ibne Khalil, Masood Jan
The Cereal Crops Research Institute (CCRI) is situated on the left bank of River Kabul, near village Pirsabak, 3 km east of Nowshera at an elevation of 288 m above sea level on the intersection of 74? E longitude and 32? N latitude. In July 2010, a devastating flood destroyed all the available germplasm, machineries, laboratories, and field equipment. After the flood research activities were restarted with full motivation, dedication and hard work in collaboration with PARC, ICARDA, CIMMYT, and with the help of wheat productivity enhancement program (WPEP). Developed new population of wheat via spring x spring, spring x facultative germplasm to elevate genetic diversity and lines selected from segregating populations for high yield and rust resistance are at advanced stage of testing.
Since the flood, the CCRI developed four new wheat cultivars: Pirsabak-2013 Pakhtunkhwa-2015 for irrigated areas and Shahkar-2013 and Pirsabak-2015 for rainfed areas of Khyber Pakhtunkhwa, Pakistan. Varietal maintenance and seed production of the released varieties has been undertaken by the wheat breeding team effectively. The seed of these newly developed wheat cultivars was multiplied on fast track basis through pre-released seed multiplication and now these four varieties are the most popular cultivars of Khyber Pakhtunkhwa, Pakistan. Three new candidate wheat lines (PR-106, PR-110 and PR-112) have been submitted to provincial seed council for approval as new wheat cultivars for Khyber Pakhtunkhwa, Pakistan. Two new candidate lines i.e. PR-115 and PR-118 got first position in National Uniform Wheat Yield Trials (NUWYT) on the basis of grain yield during 2016-17 under irrigated and rainfed conditions, respectively.
University of Delhi South Campus, New Delhi
Towards understanding the molecular mechanisms of heat stress tolerance, we have analyzed heat stressed substractive cDNA libraries and undertaken genome-wide transcriptome exploration for genes associated with spike photosynthetic efficiency during thermal stress. The photosynthetic efficiencies of Aegilops tauschii and Ae. speltoides were also compared. While the former displayed nearly complete recovery of PSII, the adverse effect was more pronounced in the latter. Functional characterization of heat stress-associated transcription factors and thermal stress-associated proteins was also undertaken e.g. TaHSF, TabZIP, TaZnF and TaMIPS, and TaLTPs in the Indian wheat germplasm. Functional characterization of the three heat stress transcription factors was upregulated under high temperatures and other abiotic stresses. They also showed early flowering and better performance with respect to their growth and yield after heat stress. Additionally, we have identified various interacting components associated with thermal stress-mediated plant signaling partners during thermal stress.
QAAFI, The University of Queensland
Robert McIntosh, Peng Zhang, Sami Hoxha, Adnan Riaz, Burkhard Steuernagel, Brande Wulff, Evans Lagudah, Lee Hickey, Sambasivam Periyannan
Wheat is one of the most important staple food and agricultural crop cultivated worldwide. To meet the demands of the raising human population, global wheat production has to be increased which is however declined due to appearance of highly virulent strains of Puccinia striiformis f. sp. tritici (Pst) fungus causing stripe rust disease. Globally, the incidence of stripe rust is effectively managed through the deployment of host plant mediated genetic resistance. But as the resistance present in the current wheat cultivars are ineffective, new sources of resistance particularly from pathogen unexposed genetic resources are of urgent need to prevent stripe rust epidemics. Landrace collections with rich genetic diversity and being less exposed to prevalent pathogen are of valuable source for resistance to new pathogens. In this study, a total of 295 landrace accessions collected by the famous Russian botanist Vavilov was screened for stripe rust resistance using the two predominant lineage Pst strains of Australia. Six accessions with good resistance against the two aggressive Pst strains were selected for genetic characterization and for utilization in global wheat breeding. Characterisation of these novel resistance were undertaken using combination of conventional and advanced genetic tools. While the conventional approach involves the traditional map based gene cloning, the other tool is the recently identified rapid method based on mutagenesis, targeted gene capture and next generation sequencing called "MutRenSeq". Subsequently, the identified novel resistant traits were transferred into elite wheat cultivars through the combination of linked molecular markers and speed breeding techniques. Thus along with the identification of novel resistance, elite wheat cultivars with broad spectrum stripe rust resistance were also generated through the use state of art techniques to sustain global wheat production from the rapidly evolving stripe pathogens.
Agriculture & Agri-Food Canada
Wheat cultivar McNair 701 carries resistance gene SrMcN and is used as a differential line to identify Pgt races using the international letter code nomenclature. The inheritance and location of the resistance gene has not been characterized. We developed a doubled haploid (DH) population from cross LMPG/McNair 701 to study the genetics and chromosomal location of SrMcN. A DH population inoculated with race QCCJB segregated 100 resistant : 94 susceptible, a 1:1 ratio (?2=0.186, P=0.666, NS) indicative of segregation at a single locus. This gene was mapped to chromosome 2DL using the Infinium 90k platform. The map position of SrMcN was similar to that of Sr54, one of two genes previously found in Norin 40. Comparison of stem rust seedling reactions using 12 diverse Pgt races indicated that McNair 701 and an Sr54 line derived from Norin 40 had an identical pattern of responses and similar low infection types (IT=12-) to races LCBNB and QCCJB. Based on the chromosomal location on 2DL and identical seedling responses to Sr54, it is likely that the resistance gene in McNair 701 formerly known as SrMcN is Sr54. This finding will be confirmed by a test of allelism.
James Winans, Julian Garcia, Kellie Damann, Gary Bergstrom
In addition to causing Fusarium head blight of wheat and other cereals, Fusarium graminearum is associated with dozens of wild or weedy grass species. Their role in the disease cycle and evolution of the pathogen has not been established despite their widespread distribution. A three-year survey of wild grasses in New York (USA) found that inflorescences and overwintered stems were frequently colonized by F. graminearum. Through a series of controlled laboratory experiments, wheat and five common grass species were compared for their potential to support inoculum production. Artificially infested stem tissue from several grasses both retained F. graminearum at higher rates through a single winter and supported greater ascospore production per dry gram than wheat. Susceptibility of these species to root and crown rot was measured with a modified seed germination assay and a diverse panel of F. graminearum isolates. Differences were seen between host species, and some grasses were resistant to infection. Our results indicate that wild grass species may support significant F. graminearum inoculum production while differing in their suitability for root and crown colonization. Studying interactions between F. graminearum and alternative host plants can improve our understanding of evolution in a broad host range pathogen and our ability to predict the risk of crop epidemics. We are currently evaluating isolates collected from wild grasses for mycotoxin production and aggressiveness on wheat.
National Institute of Agricultural Research
Nsarellah Nasserlhaq, Wuletaw Tadesse, Ahmed Birouk
In the context of climate change, drought is one of the most important and complex abiotic stresses affecting crop production worldwide. The adoption of an appropriate technological package, principally drought tolerant varieties, may overcome these challenges to meet global food security needs for the rapidly growing human population, particularly in developing countries. Therefore, this research was carried out to identify efficient phenotypic and genetic selection criteria to identify drought tolerant wheat varieties. In this perspective, 200 diverse elite bread wheat lines from ICARDA and CIMMYT were evaluated under four Moroccan environments during the 2015 and 2016 seasons for yield and 15 agro-physiological traits. The same set of genotypes was genotyped using 15k SNPs. Significant environment and genotype environment interaction effects were observed for yield. Average yield reached 3.18t/ha and ranged from 2.45 to 4.27t/ha. The secondary traits were mostly dominated by the environment effect (p<0.001). Based on correlation and regression analysis between grain yield and phenotypic data, the biomass, grain number per m<sup>2</sup> and to a lesser extent fertile spikes number and thousand kernel weights (depending of drought scenarios) can be more reliable traits than yield for the identification of drought tolerant genotypes. Moreover, the ground cover and canopy temperature depression can be used as supplementary criteria for more accurate selection. Slow selection on the basis of phenotypic traits may be accelerated and improved by using molecular markers. The genetic analysis highlighted significant SNPs and identified new QTLs linked to yield and the most efficient phenotypic traits under drought conditions. These findings could be useful for breeding drought-resistant wheat cultivars using marker-assisted selection to accumulate these favorable alleles of SNPs associated with yield-related traits to increase grain yield.
Jamal El Haddoury, Ahmed Amri
Malika', a hard red spring wheat (Triticum aestivum L.) cultivar developed using doubled haploid technology by the Institut National de la Recherche Agronomique (INRA), Morocco, and tested as 06DHBW48, was approved for release in 2016 by the Office National de S?curit? Sanitaire des Produits Alimentaires (ONSSA), Morocco. Malika was selected from the doubled haploids derived from the cross 'Achtar3*//'Kanz'/Ks85-8-4). Achtar and Kanz are Moroccan varieties originating from segregating populations from CIMMYT. Achtar and Kanz are a well adapted to Moroccan conditions but susceptible to the Hessian fly, yellow rusts and some races of leaf rust. 'Achtar' was crossed with it in order to incorporate the Hessian fly resistance, yellow rust resistance and leaf rust resistance and 'Achtar' was crossed with Kanz/Ks85-8-4 having resistance to Hessian fly, yellow rust and leaf rust. Backcrossed 3 times with 'Achtar', and selected lines having resistance to the Hessian fly, yellow rust and leaf rust from the population derived from each backcross. Finally the selected the resistant line was used develop doubled haploids. The doubled haploid lines produced were tested in the laboratory and field for Hessian fly and the rust resistance. The resistant lines were incorporated in the multi-local yield trials and three promising lines with the resistance to Hessian fly, yellow rust and leaf rust and better yield and quality were submitted for registration in the official catalog in 2014. After 2 years of testing (years 2014-15 and 2015-16), one line (06DHBW48) was accepted for the registration and designated as 'Malika'. 'Malika' is a semi-dwarf variety, well adapted to semi-arid regions, early maturing, high yielding, tolerant to drought and resistant to Hessian fly, leaf rust and yellow rust.
Sathguru Management Consultants
Kanan Vijayaraghavan, Venugopal Chintada, Rituparna Majumder, Richa Kapur, K. Aishwariya Varadan
South Asia has the highest "wheat dependent" low income community in the world. Stem rust and blast are recognized as the most damaging disease of wheat in the region producing 19% of the world's wheat. In order to combat the potential threat the national research centers were geared up to track the real time movement of wheat diseases, generate disease incidence data and create an enabling environment to boost wheat research in the region through streamlined efforts and enhanced SAARC tool box deployed six years ago.
Recent data (2016-17) from the tool box has shown a significant increase in the data records captured in this region compared to previous years. This has been possible because of heightened awareness amongst the scientists and with the continuous capacity building through pre-season and in-season surveillance trainings organized by Sathguru in collaboration with National Wheat Research Institutes at various levels.
The model is helping partner institutes to be self-sufficient for generating, maintaining wheat disease surveillance data in national and global databases and exchanging real time information with stakeholders. The application have been widely deployed and competently being used by 95% of rust surveillance teams in the wheat fields of SAARC region.
The study will focus on how national research center's judicious decision of carrying out diligent surveillance during the season contributed to safeguarding wheat crops in their respective nations through increased vigilance on emergence of new races and targeted introduction of regionally resistant varieties. Further using this data scientist's can aim to strategize their wheat research for identification of resistant varieties and eventually resulting in increased productivity addressing food security of the region.
Wheat Research Institute, AARI, Faisalabad, Pakistan
Ghulam Mahboob Subhani, Makhdoom Hussain, Mehvish Makhdoom
Rust is the single largest factor limiting wheat production in Pakistan. According to the FAO reports, countries in the predicted immediate pathway of Ug99 grow more than 65 million hectares of wheat, accounting for about 25% of global wheat harvest.
Rice, a member of the same family (Poaceae) is not attacked by any rusts. Wheat, an allo-hexaploid is responsive for wide crossing. It has previously been successfully crossed with its several wild relatives and different other crop species like corn, pearl millet etc. Based on the above facts wheat ? wild rice crossing has been attempted to incorporate rust resistance from rice to wheat. Successful crosses were made under in-vitro conditions. Surviving plantlets developed from these crosses were assayed for any genetic material introgressed from rice. Different cytological / molecular techniques were used to detect the introgression (Squash preparations from root tips, FISH, GISH, SSR etc.). Two hundred and fifty primers specific to rice chromatin were used to look for the introgression of rice chromatin into hybrids. Seven primers amplified the fragments in hybrids indicating the possible introgression of rice chromatin in wheat x rice hybrids but in-situ hybridization didn't confirm that introgression. So further testing of these hybrids is needed.