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20212
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Subject: Agricultural Biotechnology × End date: 2021 × Start date: 2021 × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Characterization of novel mutants of hexaploid wheat (Triticum aestivum L.) for isolation of mutants with higher content of micronutrients and lodging tolerance
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2021-03) Bisht, Darshana; Sundip Kumar
    Producing nutritious and safe foods sustainably and sufficiently is the ultimate goal of modern agriculture. Mutagenesis is one of the powerful genetic strategies for crop improvement programmes. A chemically induced mutated genetic resource for detecting novel variations has been developed in bread wheat (Triticum aestivum) cultivar DPW-621-50. 1536 EMS-induced wheat mutant lines along with 4 checks grown during the Rabi season of 2019/2020 were evaluated for variability parameters, correlations and path coefficients for thirteen quantitative traits i.e., plant height, number of tillers per plant, flag leaf length, flag leaf width, flag leaf area, ear length, peduncle length, number of spikelets per spike, number of grains per spike, grain length, grain width, 1000 grain weight and grain yield per plant. Significant genotypic differences were observed for all the traits studied indicating considerable amount of variation among mutant lines for each character. The cluster analysis grouped these mutant lines into 40 different clusters. Grain yield per plant showed highly significant positive correlation with number of tillers per plant, number of grains per spike, thousand grain weight, number of spikelets per spike, plant height, grain width, grain length, ear length peduncle length. Path coefficient analysis revealed that number of tillers per plant had the highest direct effect on grain yield per plant. Prior efforts have focused on raising crop yields, but enhancing the concentrations of mineral micronutrients has become an urgent task because about half of the world population suffers from the malnutrition of iron and zinc. The overall impact of this high concentration of micronutrients is directly based on their bioavailability which is influenced by antinutritional (tannins and phytic acid) and nutritional (ascorbic acid) factors. This mutant population was used to isolate the mutants containing higher contents of minerals (Fe and Zn) in grains. Mutant lines namely, BSM 410, BSM 531, BSM 659, BSM 580, BSM 531, BSM 5, BSM 804, BSM 485, BSM 518, BSM 644, BSM 611, BSM 1004, BSM 390, BSM 990, BSM 609, BSM 97, BSM 567 and BSM 380 were found to possess high Fe and Zn and low phytic acid content. BSM 379, BSM 11, BSM 462, BSM 558, BSM 647, BSM 344, BSM 49, BSM 54, BSM 44, BSM 269, BSM 348, BSM 560, BSM 386, BSM 354, BSM 556, BSM 373, BSM 3, BSM 583, BSM 419 and BSM 580 were found to contain high Fe and Zn and low tannic acid content. BSM 549, PMW-2016-1, BSM 348, BSM 483, BSM 455, BSM 558, BSM 591, BSM 523, BSM 74, BSM 31, BSM 863, BSM 347, BSM 360, BSM 531, BSM 532, BSM 24, BSM 373 and BSM 408 were found to contain high Fe and Zn and high ascorbic acid content in comparison to parent. From the newly developed mutant population, we have also identified a putative lodging tolerant plant (PMW-2016-1). Comparative anatomical studies of the culm of lodging tolerant plant (PMW-2016-1) and parent (DPW-621-50) were carried out by means of various microscopic techniques coupled with chemical studies. It was found that the culm of PMW-2016-1 possessed greater stem diameter, thicker width, higher thickness-diameter ratio and higher percentage of mechanical tissue, comparing with its parent. Furthermore, the lignin content was determined by Klason’s method. The result showed that Klason lignin content in the novel mutant (PMW- 2016-1) was higher than that in its parent genotype (DPW-621-50). Estimation of mechanical stem strength with Universal Tensile Machine exhibited that the force required to break the straw of lodging tolerant mutant wheat PMW-2016-1 is greater as compared to the straw of control (DPW-621-50). Bending of stems of mutant PMW-2016-1 and control (DPW-61-50) was analyzed by using the prostate tester. Stem strength of mutant PMW-2016-1 was found to be significantly higher than the control (DPW-61-50). Therefore, it is suggested that newly identified mutant PMW-2016-1 can be used as variety or as a donor parent for the development of lodging tolerance in wheat cultivars. This mutant population may serve as new genetic resource for functional genomics studies and novel variants for different traits in elite germplasm can be made available to the plant breeders for wheat improvement.
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    ThesisItemOpen Access
    Isolation, cloning and in silico analysis of drought responsive EcMyb1 transcription factor gene from Eleusine coracana
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2021-01) Bhatt, Megha; Lohani, Pushpa
    Myb genes are members of a family of transcription factors that play an important role in cell division, differentiation, response to abiotic stress etc. It has been reported that MYB transcription factor play an important role as a master regulator and modulates the expression of various downstream genes involved in drought stress response. The partial sequence of Ecmyb1 gene was isolated and submitted to NCBI with accession number JN107890.1. In present study, full length Ecmyb1 gene was isolated and cloned. The cloned fragment was sequenced and submitted to NCBI with accession number MT312253. For expression analysis of Ecmyb1 gene, finger millet drought tolerant variety PRM 6107 was given three different abiotic stress treatment i.e. drought, salt and heat stress. The expression of the gene increased from 12 to 28 fold under drought stress as compared to control. Similarly, in salt and heat treated plants, expression increased from 7 to 29 fold and 19 to 46 fold respectively. The cloned gene was introgressed into Arabidopsis thaliana plant by floral dip method. The transformed plants were selected by hygromysin screening and confirmed by PCR using hygromycin primers. Insilco analysis of Ecmyb1 gene was carried out using various softwares. Promoter analysis of Ecmyb1 gene revealed the presence of various regulatory elements like ABA responsive elements (CACT GG), stress responsive elements (AAGG GG), Myb recognition sites (CAACAG), Myb binding sites (CAAC TG), CpG island and tandem repeats. Homology and phylogenetic analysis of Ecmyb1 gene and amino acid sequences showed similarity with other MYB proteins such as Sateria italica, Hordeum vulgare, Saccharum barberi and Oryza sativa etc. Motif analysis predicted the presence of HTH domain in EcMYB1 protein. Subsequently, it was computed that EcMYB1 protein is water soluble, thermostable and slightly acidic in nature. Additionally, it was observed that EcMYB1 protein contains 28% alpha helix, 5.43% extended strand, 2.57% beta turn and 64% random coil. 3-D structure of EcMYB1 using swiss model predicted that 90% aminoacid residues were in Ramachandran favored region with no bad angles. It indicated that EcMYB1 protein may exist in nature.