National Research Council of Canada (NRC)-Saskatoon
Kerry Boyle, Tammy Francis, Peng Gao, Brittany Polley, Christine Sidebottom, Brent McCallum, Harpinder Randhawa, Tom Fetch, Randy Kutcher, Sylvie Cloutier, Pierre R. Fobert
Most rust resistant genes in wheat are race-specific (R), with relatively few genes conferring resistance only at the adult stage that have been described as slow rusting genes (APR). Pyramiding multiple R, APR or APR+R genes has been used successfully over many years to achieve durable rust resistance. To further enhance this strategy, a genetic genomics approach was exploited to identify genes with different resistant mechanisms and the most effective gene pyramids.
Several new combinations of rust genes were created and tested in the Thatcher background, revealing synergistic ("booster") effects involving Lr21 with Lr16. With QTL mapping approach, we found that genes combined from 7D, 1B and 7B conferred an almost immune response to leaf rust, while genes from 7D, 1B and 3B provided an almost immune response to stripe rust. With a genomics approach, a large scale transcriptome analysis was conducted on key rust resistant genes including six R genes, three APR genes and one gene pyramid with Lr34+Lr16 over a time series during the infection process of both seedlings and adult plants. Detailed transcriptome analysis of gene expression associated with different major and minor leaf rust genes, alone or in combination, identified common and unique aspects of defense responses. For example, Lr9 is different from the other three leaf rust genes tested, with resistance triggered at a very early stage, consistent with pre-haustorial resistance. R genes Lr21 and Lr16 were also significantly different compared to other R and APR genes. With gene co-expression network analysis, a shared unique gene module mediated by Lr34 and Lr67 was also identified. This large transcriptome dataset also allowed the development of a rust-wheat interactome atlas for rust functional genomics research in wheat.
Agharkar Research Institute Pune
Vijendra Baviskar, Balgounda Honrao, yashavanthakumar kakanur, Vilas Surve, Deepak Bankar, Vitthal Gite, Ajit Chavan, Vijay Khade, Juned Bagwan, Shrikant Khairanar, Sameer Raskar
Frontline demonstrations (FLDs,) on wheat were conducted by Agharkar Research Institute, Pune, during last five rabi seasons from 2012-13 to 2016-17 at farmer's fields of Pune and Satara district under wheat growing area of semi-arid tropics of western Maharashtra, India. Before conducting FLDs, a group meeting held every year in the selected village and specific skill training had imparted to the randomly selected farmers regarding adoption of different improved aspects of cultivation. FLDs comprised of improved wheat varieties viz., MACS 6222, MACS 6478, MACS 3125 (d) and MACS 2971(dic) for Peninsular Zone of India. About 50 ha of FLDs on improved wheat varieties were conducted with active participation of 50 farmers covered an average of 10 farmers and 10 ha per year. Two recent varieties, MACS 6222 and MACS 6478 had shown higher grain yield, ranging between 15 to 55 per cent more over local check and farmer practice than all other FLDs. Recommended packages and practices of wheat FLDs gave higher value of yield, net return and high benefit cost ratio as compared to local check over the years of study. The study has revealed that five years mean extension gap of 4.48 to 9.67 q/ha and technology gap ranging between 11.00 to 22.22 q/ha depending on the variety during the period of study. Net returns of Rs. 63042/ha was observed from improved practice than in the farmer's practice of Rs. 50108/ha and with benefit cost ratio of 3.07 and 2.79 respectively. On average basis, the incremental benefit cost ratio was found as 2.83. In frontline demonstrations, the yield potential of wheat has been enhanced largely due to the increase in the knowledge of farming community and adoption of improved production techniques by farmers.
Cereal Laboratory, Wheat Research Institute, Faisalabad, Punjab, Pakistan
Hira Shair, Anjum Javed, Muhammad Abdullah, Makhdoom Hussain, Javed Ahmed
Globally, more than two billion people are undernourished in the world and deficient in key vitamins and minerals, making it the world's greatest health risk factor. Among these, iron and zinc are of greater significance from human nutrition perspective, ranking them 5th and 6th in developing countries. The population most vulnerable to these micronutrient deficiencies is women and children. Iron deficiency results about 1.62 billion people as anemic, largely preschool children (47%). It is responsible for approximately 20854 deaths and two million disability adjusted life years (DALYs) among children under five years old, whereas, zinc deficiency is responsible for approximately 4% of deaths and 16 million DALYs, among children under age five. This leads to malnutrition ultimately leading to a disabled society.
Widespread accessibility of these nutrients is the solution to cater malnutrition. Wheat, the "staff of life," consumed by masses can help eradicate "hidden hunger." For this, fortification and bio-fortification are highly talked about, but one having limitations in reaching the masses and other a long term intervention, respectively, suitability of planting times to screen out varieties high in zinc and iron, is an on-field solution. In a study, wheat varieties; Punjab-11, Millat-11 and Galaxy-13 were selected from three planting times, with an interval of one month. Results reveal varieties exhibited their natural genotypic response but planting time impact on Zn and Fe were visibly significant. 30th December gave higher contents of Fe and Zn as compared to previous planting dates of the same year. Iron on an overall basis ranged from (135.0-147.0) ppm, while Zinc gave a confined range of (30.2-33.2) ppm. Thus, concluded that comparatively delayed sowing favours the mineral content concentration in wheat grains. And these creamed out varieties can readily be used in crosses with high yielding varieties, in order to make our wheat mineral sufficient.
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.
Institute of Evolution and the Department of Evolutionary and Environmental Biology, University of Haifa, Israel
Dina Raats, Lin Huang, Valeria Bocharova, Jorge Dubcovsky, Abraham Korol, Tzion Fahima
Wild emmer wheat (Triticum dicoccoides, (DIC)) is an important source of resistance to stripe rust due to presence of Puccinia striiformis in its natural habitats with high humidity and relatively low temperatures that are favorable for stripe rust development. Previously, we showed that DIC accessions from northern Israel were highly resistant to stripe rust. According to the rust responses of three DIC accessions (G25, H52, G303) and mapping of the resistance to relatively close, but different, genetic positions on chromosome 1BS, three different resistance genes were assumed to be present. However, the development of additional critical recombinants and new higher resolution genetic maps for these three genes in subsequent work led us to place YrH52 and YrG303 in the same genetic interval as Yr15, suggesting that the three putative genes are allelic or identical. The recent cloning of Yr15 allowed us to test this hypothesis using an EMS mutagenesis approach. We sequenced the Yr15 locus in five yrH52 and three yrG303 susceptible mutants and identified missense point mutations associated with the susceptible phenotype in each one. Thus, YrH52 and YrG303 may not be new genes. Further work is under way to determine if these genes are allelic or identical.
Wheat Research Institute, Faisalabad, Pakistan
Javed Ahmad, Abid Mahmood
Wheat is an important cereal crop and staple food in Pakistan. Most of the wheat is cultivated late after cotton, rice and sugarcane. Introduction of long duration Bt cotton varieties further pushed its sowing to late December or even early January. Late sowing of wheat crop results in yield loss in the Punjab province. A study has been conducted in experimental fields of Wheat Research Institute, AARI, Faisalabad, Pakistan to find out the possible reasons of low grain yields in late sown crop. Twelve experimental wheat lines were planted on seven sowing dates starting from 1st November to 30th December with ten days interval. The experimental design was a factorial combination of seven sowing dates as main plots and twelve varieties/ genotypes as subplots in a split-plot design with three replications. Effect of temperature on several crop growth stages was studied. Mean minimum temperature during the month of December, 2016 and January, 2017 remained below 5?C and mean maximum was more than 30?C during March 2017. Weather conditions experienced by the crop at each developmental stage were compared with the optimum conditions required on that specific stage in each sowing date. It was revealed that in late sown crop, different phonological/growth stages of the crop and yield components and grain yield were affected negatively. It was concluded from the study that the late sown crop suffered from two types of temperature stresses. The late sown crop faced low temperature stress at starting phase which result in delayed germination and low tillering. At caryopsis formation and grain filling the same crop face high temperature stress causing reduced grain formation and shriveled grains due to enforced maturity. Sowing of wheat at proper time i.e., by the end of November was recommended to fetch maximum yields.
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.
College of Plant Protection, Northwest A&F University, China
Yuanyuan Zhao, Shuxia Zuo, Dan Zheng, Lili Huang, Zhengshen Kang
Wheat stripe rust, caused by basidiomycete fungus Puccinia striiformis f. sp. tritici (Pst), is a damaging disease worldwide. The recent discovery demonstrated the fungus depends on living wheat and aecial hosts, mainly barberry (Berberis) species, to complete its life cycle. In China, we determined that, under natural conditions, the sexual cycle of Pst occurs based on collections of Pst isolates from the diseased barberry in the past three years. However, no direct evidence to support whether barberry plays a role in spreading inoculums to wheat field to cause stripe rust was detected. In the present study, we recovered 103 Pst samples from natural-infected B. shensiana in the western Shaanxi in spring 2016, and also collected 107 Pst isolates from neighboring wheat fields. Phenotype and genotype of the two Pst populations were tested using a set of Chinese differential hosts for Pst and SSR markers, respectively. The phenotype tests showed that 57 race types produced from the barberry-derived Pst populations, consisting of 58 known races, such as CYR 34, CYR32, G22-14, and Su11-14-3, and 45 new races. Many of the two Pst populations shared the same race types. The genotype tests indicated the barberry-derived Pst population produced a rich genotype, obviously higher than the wheat-derived Pst populations. The seven same genotypes were found on 40 isolates of the former and 26 of the latter. Our results provide evidence to support that sexual cycle of Pst occurs regularly in nature in China and that barberry provides inoculums to neighboring wheat fields, triggering stripe rust infections in the spring. This could be a reason why the Chinese Pst populations represent extreme genetic diversity.
Laboratory of Molecular Plant Physiology, Biotechnology Center of Borj Cedria (CBBC)
Mahmoud Gargouri, Hesham A.Y Gibriel, Richard B. Todd, Michael F. Seidl, Gerrit H.J. Kema
Septoria tritici blotch disease, caused by the fungus Zymoseptoria tritici, is a major threat to global wheat production. With the recent advances in high-throughput DNA-based technologies, Z. tritici has become a powerful model system for the discovery of candidate determinants that underlie virulence and host specialization. Although a few important virulence/regulatory genes have been identified, a global understanding of the larger regulatory network has not been developed. Therefore, to uncover the transcriptional regulatory networks of the infection cycle and most particularly the regulatory hubs that control the switch between the biotrophic and necrotrophic phases, we applied an integrated approach combining transcriptomics, proteomics, and metabolomics analyses based on the identification of plant and fungal transcription factors and regulators, which we characterized from the newly annotated genome sequence of the reference isolate IPO323 (Grandaubert et al., 2015) and using datasets from Rudd et al. (2015). Bread wheat transcription factors and regulators were identified by querying the proteome and subsequent categorization from the Plant Transcription Factor database (PTFDB). Similarly, Z. tritici transcription factors and regulators were identified and categorized using the PFAM TF family databases, and following fungal transcription factor rules as outlined by Todd et al. (2014) and rules we developed for fungal transcription regulators. Insights into transcription factors and regulators will enable synthetic biology approaches to alter the Z. tritici-wheat interaction and lead to rewiring of the regulatory networks thereby turning off the fungal infection process. Beyond providing insights into the regulatory systems-levels involved in Z. tritici-wheat interaction, we believe that our dataset and approach sets the stage for an emerging series of studies that will decipher the dynamic regulatory networks in other plant-pathogen interactions.
Department of Plant Molecular Biology, University of Delhi South Campus
L-myo-inositol phosphate synthase (MIPS; EC 220.127.116.11) have been involved in abiotic stress tolerance and its disruption leads to spontaneous cell death and enhanced tolerance to pathogen. However, its molecular mechanism underlying role of MIPS in growth, immunity and abiotic stress tolerance remains unknown. To delve deeper into the conserved molecular mechanism of MIPS action during growth and stress condition, we characterized the overexpression transgenic of TaMIPS and mutant lines of AtMIPS1. Subsequent, transcriptome analysis revealed the activation of ET/JA dependent immune response in transgenic and SA defense response in mutant. Pull-down analysis revealed the interaction of TaMIPS2 with ethylene synthesis (ACO) and signaling protein (CTR1) component. Due to the established role of ethylene during the skotomorphogenesis, we investigated the effect of myo-inositol phosphate synthase role in ethylene response during hook formation. Our results thus suggest the requirement of MIPS for ethylene response and regulating the growth and immunity.