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Theses

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2020 - 20213
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Subject: Biochemistry × End date: 2021 × Start date: 2020 × Type: Thesis × Thesis Type: Ph.D ×
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Now showing 1 - 3 of 3
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    ThesisItemOpen Access
    Sucrose mobilization and nitrogen metabolism in aerobic and lowland indica rice (Oryza sativa L.)
    (CCSHAU, Hisar, 2020) Jhandai, Sonia; Ajay Pal
    Water dearth is the most critical issues in modern agriculture. Therefore, aerobic cultivation condition is sustainable concept to grow rice (Oryza sativaL.) which favors huge water impetus and labor. A better understanding of sucrose mobilization in shoots at vegetative and reproductive stages and developing grains at 7th–14th DAA may help in selection of rice genotypes to grow under aerobic condition. Herein, we have studied the effect of aerobic and conventional conditions on the activities of sucrose mobilization enzymes in four rice varieties viz. PAU201, HBC19 (lowland) and MAS26, MAS25 (aerobic) under pot condition. Aerobic condition significantly increased activities of sucrose synthesizing enzyme viz. sucrose phosphate synthase (SPS), sucrose phosphate phosphatase (SPP) and sucrose synthase (synthesis) (SSs). Activities of starch synthesizing enzymes viz.sucrose synthase (cleavage) (SSc), ADP-glucose pyrophosphorylase (AGPase) and soluble starch synthase (SSS) were reduced in concord with starch content under aerobic condition. Sucrose, soluble sugars, reducing and non-reducing sugars increased under aerobic condition in contrast with starch, UDP-glucose and ADP-glucose. UDP glucose pyrophosphorylase (UGPase) activity increased in shoot under aerobic condition to contribute sucrose synthesis while decreased in developing grains resulting in decreased starch content. Nitrogen, an essential component of all proteins, is one of the essential macronutrients required for better yield and therefore, nitrogen metabolism pathway was also studied under aerobic condition with respect to conventional condition and observed decreased activities under aerobic condition in both shoots and roots. Similar to enzymes, diminished metabolites viz. nitrite and alanine were observed under aerobic condition Crop sustainability under aerobic condition in all varieties could be attributed to osmoprotective role of sucrose and total soluble sugars. Our findings by semi-quantitative RT-PCR analysis also revealed up-regulation of SPS with down-regulation of AGPase and SUS transcript under aerobic condition is responsible for significant decrease in starch with increase in sucrose. Our results reveal decreased yield attributes under aerobic condition. Biochemical analysis, gene expression and yield attributes highlight the role of various enzymes prioritized for assimilate translocation under aerobic condition, and provide evidence of differentiation of metabolic pathway under two growing condition as well as aerobic and lowland rice varieties.
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    ThesisItemOpen Access
    Biochemical studies on antioxidative defense system in advance lines of wheat (Triticum aestivum L. em Thell.) grown under salt stress
    (CCSHAU, Hisar, 2021-08) Bhadu, Surina; Tokas, Jayanti
    Wheat (Triticum aestivum) is an important cereal crop for the world population. Based on productivity, wheat is the third most commonly grown cereal after maize and rice. It is essential for providing the mandatory amount of calories and protein content in the affluent human diet. Among abiotic stresses, salt stress is the chief reason which affects approximately 50% of crop productivity along with soil fertility. Under saline conditions, there is an imbalance in the uptake of the ions which disturbs the homeostasis between Na+/ K+ ratio. Due to the ions imbalance in plants, there is a generation of ionic and osmotic stress at the cellular level. The excess amount of ROS produced is the consequence of this stress which damages the membrane integrity that causes several changes at physiological, morphological, biochemical, and molecular levels. The present study was carried out on F5 and F6 generation of a conventional wheat cross between Kharchia 65 (salt-tolerant) × WH1105 (saltsensitive). The F5 generation was sown at 8 ECe while F6 was sown at 10 ECe and analyses were carried out at vegetative and reproductive stages. Under salt stress, WH1105 had higher oxidative stress components viz. H2O2, MDA which increased in response to the ROS and antioxidative defense system got activated to scavenges the excess of ROS. Kharchia 65 (salt-tolerant) showed higher antioxidative enzyme activities than WH1105 (salt-sensitive) under salt stress at both vegetative and reproductive stages. Introgress of Nax1 and Nax2 genes was much affective in increasing the antioxidative enzyme activities viz. at vegetative stage, SOD (1.33%, 4.50%), CAT(14.6%, 4.13%), APX(12.57%, 20.64%), GR (14.51%, 20.34%), GPX(13.91%, 4.34%), MDHAR (55.8%, 44.4%), DHAR (42.9%, 38.3%) and POX (10.44%, 4.29%) and at reproductive stage, SOD (3.26%, 3.25%), CAT(4.67%, 7.18%), APX(11.87%, 9.13%), GR (2.65%, 19.8%), GPX(19.16%, 8.48%), MDHAR (45.7%, 48.6%), DHAR (35.7%, 34.2%) and POX (7.58%, 7.12%) in F5 and F6 generations respectively in plants expressing Nax1 and Nax2 genes as compared to Kharchia 65 under salt stressed condition. The physiological parameter like RWC and osmotic potential declined with an increase in salinity and the Na+/K+ ratio was higher in F6 as compared to F5. The LOX activity was also higher in WH1105 indicating higher lipid peroxidation as compared to Kharchia 65. The proteomics data indicate that there is up-regulation of many proteins in the plants that expressing either Nax1 or Nax2 gene as compared to salt stressed Kharchia 65. From the present study, it is concluded that introgress of Nax1 and Nax2 genes had activated the antioxidative defense mechanism with an increase in the crop yield under salt stress.
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    ThesisItemOpen Access
    Biochemical and expression profiling of sorghum [Sorghum bicolor (L.) Moench] under salt stress
    (CCSHAU, Hisar, 2021-04) Himani; Tokas, Jayanti
    Salinity induces complex metabolic processes that involve ion toxicity, osmotic stress, biochemical and physiological perturbations. Sorghum is a gluten-free cereal crop, well adapted to semi-arid tropics, highly biomass productive, and water-efficient. Therefore, the present study aimed to assess sorghum genotypes' tolerance behavior under different salinity levels (6, 8, 10, and 12 dSm-1) concerning the performance of physiological, biochemical, and molecular responses. Amongst 23 screened sorghum genotypes, SSG59-3 was identified as salt-tolerant and PC-5 as salt susceptible genotype based on germination studies. The results revealed that at 35 and 95 DAS, morpho-physiological parameters (RWC, OP, CF, CSI, total chlorophyll content) and growth traits (plant height, fresh and dry weight, root and shoot length) decreased with increasing salt concentration. The maximum decrease was observed in PC-5 as compared to SSG 59-3 at 10 dSm-1. PC-5 accumulated higher Na+and K+ content in roots while the exclusion potential of SSG 59-3 was more in roots, so it had minimum Na+ and K+ content. The quality traits viz. HCN, CP, IVDMD, CPY, DDM, and cell wall components (except HC, which decreased with plant maturity) also followed a similar pattern. SSG 59-3 maintained the higher GFY, DMY, and yield components at 10 dSm-1 (at physiological maturity). The imposition of salinity induces the activities of ROS scavenging enzymes viz. SOD, CAT, POX, APX, GPX, GR, MDHAR, and DHAR and the content of ROS scavenging metabolites viz. ascorbate, glutathione, and carotenoids which were maximum in SSG 59-3 while lower in PC-5 at 10 dSm-1. The oxidative stress as judged by accumulation of MDA and H2O2 content was maximum in PC-5 and minimum in SSG 59-3. A significant increase was observed in compatible osmolytes viz. proline, glycine betaine, and total carbohydrates, which was more pronounced in SSG 59-3 than PC-5 at 10 dSm-1. Analysis of the LFQ results using MASCOT software revealed more than 100 differentially expressed proteins, out of which 40 proteins were upregulated, 29 proteins were down regulated and the majority was involved in catalytic activity, binding proteins, metabolic inter-conversion enzymes and ion transporters. The relative expression of CIPK24, LEA3, BADH1 was highly upregulated at 10 dS m-1while NCED3, SNAC1, GPX, H+-PPase, and P5CS1 were up-regulated at 12 dS m-1. The fold change was maximum in SSG 59-3 while the expression level of transcripts was less in PC-5. Hence, SSG 59-3 seems physiologically and biochemically promising and may be exploited in plant breeding programs aimed at developing salt-tolerant sorghum genotypes.