Satinder Kaur

Transfer of leaf rust and stripe rust resistance from Aegilops umbellulata Zhuk. to bread wheat (Triticum aestivum L.)

Aegilops umbellulata acc. 3732, an excellent source of resistance to major wheat diseases, was used for transferring leaf rust and stripe rust resistance to cultivated wheat. An amphiploid between Ae. umbellulata acc. 3732 and Triticum durum cv. WH890 was crossed with cv. Chinese Spring PhI to induce homoeologous pairing between Ae. umbellulata and wheat chromosomes. The F1 was crossed to the susceptible Triticum aestivum cv. ‘WL711’ and leaf rust and stripe rust resistant plants were selected among the backcross progenies. Homozygous lines were selected and screened against six Puccinia triticina and four Puccinia striiformis f. sp. tritici pathotypes at the seedling stage and a mixture of prevalent pathotypes of both rust pathogens at the adult plant stage. Genomic in situ hybridization in some of the selected introgression lines detected two lines with complete Ae. umbellulata chromosomes. Depending on the rust reactions and allelism tests, the introgression lines could be classified into two groups, comprising of lines with seedling leaf rust resistance gene Lr9 and with new seedling leaf rust and stripe rust resistance genes. Inheritance studies detected an additional adult plant leaf rust resistance gene in one of the introgression lines. A minimum of three putatively new genes—two for leaf rust resistance (LrU1 and LrU2) and one for stripe rust resistance (YrU1) have been introgressed into wheat from Ae. umbellulata. Two lines with no apparent linkage drag have been identified. These lines could serve as sources of resistance to leaf rust and stripe rust in breeding programs.

Introgression of a leaf rust resistance gene from Aegilops caudata to bread wheat

Rusts are the most important biotic constraints limiting wheat productivity worldwide. Deployment of cultivars with broad spectrum rust resistance is the only environmentally viable option to combat these diseases. Identification and introgression of novel sources of resistance is a continuous process to combat the ever evolving pathogens. The germplasm of nonprogenitor Aegilops species with substantial amount of variability has been exploited to a limited extent. In the present investigation introgression, inheritance and molecular mapping of a leaf rust resistance gene of Ae. caudata (CC) acc. pau3556 in cultivated wheat were undertaken. An F2 population derived from the cross of Triticum aestivum cv. WL711 – Ae. caudata introgression line T291-2 with wheat cultivar PBW343 segregated for a single dominant leaf rust resistance gene at the seedling and adult plant stages. Progeny testing in F3 confirmed the introgression of a single gene for leaf rust resistance. Bulked segregant analysis using polymorphic D-genome-specific SSR markers and the cosegregation of the 5DS anchored markers (Xcfd18, Xcfd78, Xfd81 and Xcfd189) with the rust resistance in the F2 population mapped the leaf rust resistance gene (LrAC) on the short arm of wheat chromosome 5D. Genetic complementation and the linked molecular markers revealed that LrAC is a novel homoeoallele of an orthologue Lr57 already introgressed from the 5M chromosome of Ae. geniculata on 5DS of wheat.

Effect of pig dung on water quality and polyculture of carp species during winter and summer

Theeffect of pig dung, as pond manure [at 18 and 36 tha−1 yr−1] and as fish feed ingredient[replacing traditional diet composed of solvent extracted rice bran and mustardcake (1:1) at 25, 50, 75 and 100% levels], was observed on water quality, pondproductivity and survival and growth of carp in polyculture system during winter(12–18 °C) and summer (18–36 °C)months. The studies on water quality parameters viz pH, dissolved oxygen andalkalinity revealed that pig dung even at higher levels (both as manure and /oras feed ingredient) did not deteriorate the quality of water, as all the waterparameters remained within the optimum ranges required for carps. The nutrient(phosphates and nitrates) status of water was significantly better in pondsreceiving pig dung as pond manure at 36 tha−1 yr−1. Pond productivity in terms ofplankton production (phyto and zooplankton) was also significantly higher innutrient rich water (36 tha−1 yr−1) both during winter andsummer. Further, in all the ponds (including control) phytoplankton levels weresignificantly higher during winter and zooplankton was higher during summer. Thestudies revealed 100% survival of all the fish species in all the treatments.During winter, the growth of carp was higher in treatments where pig dung wasused as feed ingredient (at 25% level), whereas during summer growth was higherwhere pig dung was used either as pond manure and/or as feed ingredient (athigher levels). Further, among carps, the growth of Indian major carps vizCatla catla, Labeo rohita and Cirrhinamrigala was higher during summer and that of exotic carps vizCyprinus carpio and Ctenophayrengodonidella was higher during winter.

Storage stability and quality assessment of processed cereal brans

Quality improvement of cereal brans, a health promoting ingredient for functional foods is the emerging research concept due to their low shelf stability and presence of non-nutrient components. A study was conducted to evaluate the storage quality of processed milling industry byproducts so that these can be potentially utilized as a dietary fibre source. Different cereal brans (wheat, rice, barley and oat) were processed by dry, wet, microwave heating, extrusion cooking and chemical methods at variable conditions. Processed brans were stored in high density polyethylene (HDPE) pouches at ambient and refrigeration temperature. Quality assessments (moisture, free fatty acids, water activity and physical quality) of brans were done up to six months, at one month intervals. Free fatty acid content, moisture and water activity of the cereal brans remained stable during the entire storage period. Among treatments, extrusion processing is the most effective for stability. Processing treatments and storage temperature have the positive effect on extending the shelf life of all cereal brans. Therefore, processed cereal brans can be used as a dietary fortificant for the development of value added food products.

Marker Assisted Transfer of Two Powdery Mildew Resistance Genes PmTb7A.1 and PmTb7A.2 from Triticum boeoticum (Boiss.) to Triticum aestivum (L.).

Powdery mildew (PM), caused by Blumeria graminis f. sp. tritici, is one of the important wheat diseases, worldwide. Two PM resistance genes, designated as PmTb7A.1 and PmTb7A.2, were identified in T. boeoticum acc. pau5088 and mapped on chromosome 7AL approximately 48cM apart. Two resistance gene analogue (RGA)-STS markers Ta7AL-4556232 and 7AL-4426363 were identified to be linked to the PmTb7A.1 and PmTb7A.2, at a distance of 0.6cM and 6.0cM, respectively. In the present study, following marker assisted selection (MAS), the two genes were transferred to T. aestivum using T. durum as bridging species. As many as 12,317 florets of F1 of the cross T. durum /T. boeoticum were pollinated with T. aestivum lines PBW343-IL and PBW621 to produce 61 and 65 seeds, respectively, of three-way F1. The resulting F1s of the cross T. durum/T. boeoticum//T. aestivum were screened with marker flanking both the PM resistance genes PmTb7A.1 and PmTb7A.2 (foreground selection) and the selected plants were backcrossed to generate BC1F1. Marker assisted selection was carried both in BC1F1 and the BC2F1 generations. Introgression of alien chromatin in BC2F1 plants varied from 15.4 - 62.9 percent. Out of more than 110 BC2F1 plants showing introgression for markers linked to the two PM resistance genes, 40 agronomically desirable plants were selected for background selection for the carrier chromosome to identify the plants with minimum of the alien introgression. Cytological analysis showed that most plants have chromosome number ranging from 40-42. The BC2F2 plants homozygous for the two genes have been identified. These will be crossed to generate lines combining both the PM resistance genes but with minimal of the alien introgression. The PM resistance gene PmTb7A.1 maps in a region very close to Sr22, a stem rust resistance gene effective against the race Ug99. Analysis of selected plants with markers linked to Sr22 showed introgression of Sr22 from T. boeoticum in several BC2F1 plants. Thus, in addition to PM resistance, these progeny might also carry resistance to stem rust race Ug99.

Optimization of process for reduction of antinutritional factors in edible cereal brans

Reduction of various antinutritional factors in cereal brans by different treatments (microwave heating, dry heating and wet heating) were studied. There was significant difference (p ≤ 0.05) in reduction of antinutritional factors of treated cereal brans except for dry heating at low temperature. Microwave heating at 2450 MHz for 2.5 min resulted in 53.85%, 57.21%, 65.00% and 100% reduction in phytic acid, polyphenols, oxalates and saponins, respectively. Wet heating resulted in maximum reduction in trypsin inhibitor activity (83.07%) at 110 °C for 25 min. Processing treatment resulted in increase in bulk density and slight darkening of the brans. The most effective method of detoxifying most of the toxicants was microwave heating for 2.5 min, and therefore it could be exploited for making treated brans an ideal source for potential food application.

Genome-Wide Association Study of Grain Architecture in Wild Wheat Aegilops tauschii

Aegilops tauschii, the D-genome progenitor of Triticum aestivum, encompasses huge diversity for various traits of potential economic importance such as yield, biotic and abiotic stress tolerance, quality and nutrition. In the present study, variation for grain size in Ae. tauschii germplasm was studied and its genetic basis dissected using genome-wide association study (GWAS). Grain length, width, and weight evaluated in 177 Ae. tauschii accessions over 3 years showed near normal distribution with 1.74-, 1.75-, and 2.82-fold variation, respectively. These lines were genetically characterized using genotyping-by-sequencing (GBS) protocol that produced 11,489 single nucleotide polymorphic (SNP) markers. Genetic diversity analysis revealed the presence of two distinct subgroups (designated as lineage 1 and 2) in Ae. tauschii. Based on GBS markers, the genetic similarity was calculated between the accessions and GWAS was conducted using 114 non-redundant accessions and 5,249 SNP markers. A total of 17 SNPs associated with grain size traits distributed over all the seven chromosomes were revealed with 6D, 5D, and 2D harboring most significant marker–trait associations. Some of the chromosomal regions such as 6D_66.4–71.1 cM, 1D_143.5–156.7 cM, and 2D_89.9–92.5 cM had associations with multiple traits. Candidate genes associated with cell division and differentiation were identified for some of the associated SNP markers. Further efforts to validate these loci will help to understand their role in determining grain size and allelic diversity in current germplasm and its effect on grain size upon transfer to bread wheat background.

Comparative Temporal Transcriptome Profiling of Wheat near Isogenic Line Carrying Lr57 under Compatible and Incompatible Interactions.

Leaf rust caused by Puccinia triticina (Pt) is one of the most important diseases of bread wheat globally. Recent advances in sequencing technologies have provided opportunities to analyse the complete transcriptomes of the host as well as pathogen for studying differential gene expression during infection. Pathogen induced differential gene expression was characterized in a near isogenic line carrying leaf rust resistance gene Lr57 and susceptible recipient genotype WL711. RNA samples were collected at five different time points 0, 12, 24, 48, and 72 h post inoculation (HPI) with Pt 77-5. A total of 3020 transcripts were differentially expressed with 1458 and 2692 transcripts in WL711 and WL711+Lr57, respectively. The highest number of differentially expressed transcripts was detected at 12 HPI. Functional categorization using Blast2GO classified the genes into biological processes, molecular function and cellular components. WL711+Lr57 showed much higher number of differentially expressed nucleotide binding and leucine rich repeat genes and expressed more protein kinases and pathogenesis related proteins such as chitinases, glucanases and other PR proteins as compared to susceptible genotype. Pathway annotation with KEGG categorized genes into 13 major classes with carbohydrate metabolism being the most prominent followed by amino acid, secondary metabolites, and nucleotide metabolism. Gene co-expression network analysis identified four and eight clusters of highly correlated genes in WL711 and WL711+Lr57, respectively. Comparative analysis of the differentially expressed transcripts led to the identification of some transcripts which were specifically expressed only in WL711+Lr57. It was apparent from the whole transcriptome sequencing that the resistance gene Lr57 directed the expression of different genes involved in building the resistance response in the host to combat invading pathogen. The RNAseq data and differentially expressed transcripts identified in present study is a genomic resource which can be used for further studying the host pathogen interaction for Lr57 and wheat transcriptome in general.

Genetics of leaf and stripe rust resistance in a bread wheat cultivar Tonichi

are themajor foliar diseases of wheat, resulting in yield loss all overthe world (Eversmeyer and Browder 1974; Kolmer 1996).The wheat cultivars become susceptible to rusts due to theirnarrow genetic base for resistance and the rapid rate of evo-lution of the pathogen, making it necessary to search for newsource(s) for resistance. Thus, the wheat productionhas beenlargely dependent on the development and the use of resis-tant cultivars having diverse and well characterized genes.So far, nearly 58 leaf rust and 40 stripe rust resistance geneshave been identified and designated as

Molecular characterization of α-gliadin gene sequences in Indian wheat cultivars vis-à-vis celiac disease eliciting epitopes

Abstractα-Gliadin proteins of the wheat gluten form a multigene family encoded by genomic loci Gli-A2, Gli-B2 and Gli-D2 located on the homoeologous wheat chromosomes 6AS, 6BS, and 6DS, respectively which upon partial digestion elicits celiac disease (CD) in the genetically susceptible individuals. The present investigation was planned to study the variations in the amino acid sequence of the α-gliadin proteins and CD eliciting epitopes in the Indian wheat cultivars. Representative wheat varieties released and cultivated in India during the period 1905–2011 were selected for studying the α-gliadin genes by cloning and sequencing followed by in silico analysis of the gene sequences. A lot of variation for α-gliadin gene sequences especially in T cell stimulatory epitopes glia-α9, glia-α20, glia-α2 and glia-α was observed in different wheat varieties. Modern varieties released during 1971–2011 had higher proportion of intact T-cell stimulatory epitopes. The old wheat varieties released in the period 1905–1970 on the other hand had large proportion of variant epitopes. We identified three wheat varieties namely C591, C273 and K78 having only variant epitopes at Gli-D2 and Gli-B2 and both intact and variant epitopes at Gli-A2. Identification of lower proportion of T-cell stimulatory epitopes in these three varieties is the first step towards developing a wheat variety less immunogenic for celiac disease patients. The gene sequences of the selected varieties have been submitted at NCBI with accession numbers GenBank KJ410473–KJ410488.