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2018 - 20194
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Subject: Biotechnology × Author: KAU × End date: 2019 × Start date: 2017 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    In vitro studies on anti-infective properties of leaf and root extracts of selected medicinal plants against gastro intestinal bacterial pathogens.
    (Department of Plant Biotechnology, College of Agriculture, Vellayani, 2019) Anjana, Babu; KAU; Shiburaj, Sugathan
    The thesis entitled “in vitro studies on anti-infective properties of leaf and root extracts of selected medicinal plant against gastro intestinal bacterial pathogenes” was carried out in the Microbiology division of Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Palode, during 2018-2019 academic years.The objective of the study was Screening of medicinal plant extracts for anti infective property against gastro intestinal bacterial pathogens and identification of lead compounds, targeted efficacy testing of selected compounds against FtsZ proteins through in vitro and in silico approaches, demonstrating the effect of the compounds identified on virulence factors and bio-film formation of enteropathogens. Diarrhoeal diseases remain a leading cause of preventable death, especially among children under five in developing countries. Acute watery diarrhoea mainly affecting children of developing countries that results in dramatic dehydration and it is most dangerous in the very young. Enterotoxigenic Escherichia coli or Vibrio cholerae are most common causative agent of acute watery diarrhoea. Diarrhoea also cause huge economic burden on people of impoverished countries. There is need for novel anti-infective agents that can prevent disease and economic burden of diarrhoea. Developing countries are rich source of traditional knowledge and natural resources. These resources can be channelized to develop novel anti-diarrhoeal agents that can prevent emergence and dissemination of gastrointestinal pathogen including drug-resistant strains. Many diarrhoeal diseases are known to be treated with herbal remedies throughout the history of humankind. Even today, plant materials continue to play a major role in primary health care as therapeutic remedies in many developing countries. For centuries, many secondary metabolites present in leaves are found to have an outstanding role in medical world. Most of these compounds belong to alkaloids, flavonoids, terpenoids, steroids, saponins, quinones, coumarin and tannins. Leafs and roots are been extensively used in folk and modern medicine for treating various diseases. 105 We have explored anti-infective activity of the leaf and roots ethanol extract of five medicinal plants Moringa oleifera, Bixa orellana, Persicaria glabra, Pimenta dioica and Homonia riparia against enteropathogens like E. coli, V. cholera, E. faecalis, S. Typhi and S. aureus. Among these extractes hot ethanol extracts of persicaria glabra exhibited antibacterial activity against gastrointestinal pathogens such as E. coli, V. cholera, E. faecalis, S. Typhi and S. aureus. It also induced filamentation of Bacillus subtilis 168 which is an indication of cell division inhibition. The active compound present in persicaria glabra extract was identified to be querecetin, this compound can be used to develop novel anti-diarrhoeal agents.
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    ThesisItemOpen Access
    Assesment of multiple abiotic stress tolerance mechanisms in rich (Oryza sativa L.)
    (Department of Biotechnology, College of Agriculture, Vellayani, 2019) Alif Ali, B S; KAU; Beena, R
    The study entitled “Assessment of multiple abiotic stress tolerance mechanisms in rice (Oryza sativa L.)” undertaken at the Department of Plant Physiology, College of Agriculture, Vellayani during 2018-19. The objective was to study the multiple abiotic viz. drought, salinity and high temperature stress tolerance mechanisms in rice and to validate the identified QTLs for stress tolerance in rice. The investigation comprises four experiments, In experiment I initial screening of 20 rice genotypes for single abiotic stress tolerance was studied. Stresses were induced using different concentrations of PEG6000, NaCl and temperature controlled incubator for providing drought, salinity and temperature stresses respectively. Germination study was carried out using paper towel method. In the first experiment drought stress were given at concentrations -1bar, -3bar, 5bar and -7bar water potentials of PEG6000, salinity stress was given at 100mM, 150mM, 200mM, 250mM NaCl and temperature stress were given at 350C, 400C, 450C and 500C for all 20 rice varieties with two replications. The physio-morphological and biochemical parameters were studied on 14th day of germination. The highest level drought, salinity and temperature stresses at which germination occurred was selected as Dh (-5 bar), Sh (250mM NaCl) and temperature (Th) (350C) respectively. Among 20 rice varieties, PTB-7, PTB-60 and PTB-35 showed maximum seedling vigour at highest level of drought stress (Dh) stress condition Vyttila-9, MO-18 and Vyttila-3 recorded maximum seedling vigour index at highest tolerated level of salinity (Sh) stress condition and N-22, NL-44 and Vyttila -6 showed maximum seedling vigour index at highest tolerated level of temperature stress (Th) stress condition. These nine genotypes were selected for the evaluation of combination stress treatment In the second experiment, The combination stress treatments given were Dh x Sh, Dh x Th, Th x Sh and Dh x Sh x Th. Rice varieties did not germinated at Dh x Sh and Dh x Th. The maximum seedling vigour index at Dh x Sh and combination stress treatment was observed in PTB-7, Vyttila-9, PTB-35 and at Th x Sh was observed in NL-44, MO-18 and N-22 respectively. These rice varieties were selected as tolerant varieties. In experiment III six rice varieties selected from combination stress treatment were evaluated for yield parameters in pot culture experiment. The design of the experiment was CRD with two replications and one control. Drought and salt stress were imposed during reproductive stage for 5 days by applying -5bar PEG6000 and 250mM NaCl solutions respectively into the pots containing rice varieties, Temperature stress was induced using a temperature controlled polyhouse from panicle initiation to maturity stage. Physio-morphological, biochemical and yield parameters were studied under the combination stress treatments. Highest yield under the combination stress treatment of Dh x Sh was observed in PTB-7 and highest yield under the combination stress treatment Th x Sh was observed in N-22. Based on morpho-physiological and yield parameters PTB-7 was selected as the tolerant variety under drought and saline condition and N-22 was selected as the tolerant variety under temperature and salinity condition. In experiment IV all the 20 genotypes were analyzed for the identification of reported markers linked to stress tolerance such as drought salinity and temperature. Reported microsatellite markers linked to drought, salinity and temperature were used to screen 20 rice varieties. Among the markers distinct polymorphism for temperature tolerance between temperature tolerant (N-22 and NL-44) and susceptible varieties was shown by RM 6100. RM 7076 showed distinct polymorphism in tolerant varieties PTB-7 and NL-44 . RM 1287 showed distinct polymorphism for salinity tolerance in PTB-7 and N-22. Drought tolerance between drought tolerant (PTB-7) and susceptible varieties was Shown by RM 490.
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    ThesisItemOpen Access
    Assesment of multiple abiotic stress tolerance mechanisms in rice (Oryza sativa L.)
    (Department of Plant Biotechnology, College of Agriculture,Vellayani, 2019) Alif Ali, B S; KAU; Beena, R
    The study entitled “Assessment of multiple abiotic stress tolerance mechanisms in rice (Oryza sativa L.)” undertaken at the Department of Plant Physiology, College of Agriculture, Vellayani during 2018-19. The objective was to study the multiple abiotic viz. drought, salinity and high temperature stress tolerance mechanisms in rice and to validate the identified QTLs for stress tolerance in rice. The investigation comprises four experiments, In experiment I initial screening of 20 rice genotypes for single abiotic stress tolerance was studied. Stresses were induced using different concentrations of PEG6000, NaCl and temperature controlled incubator for providing drought, salinity and temperature stresses respectively. Germination study was carried out using paper towel method. In the first experiment drought stress were given at concentrations -1bar, -3bar, 5bar and -7bar water potentials of PEG6000, salinity stress was given at 100mM, 150mM, 200mM, 250mM NaCl and temperature stress were given at 350C, 400C, 450C and 500C for all 20 rice varieties with two replications. The physio-morphological and biochemical parameters were studied on 14th day of germination. The highest level drought, salinity and temperature stresses at which germination occurred was selected as Dh (-5 bar), Sh (250mM NaCl) and temperature (Th) (350C) respectively. Among 20 rice varieties, PTB-7, PTB-60 and PTB-35 showed maximum seedling vigour at highest level of drought stress (Dh) stress condition Vyttila-9, MO-18 and Vyttila-3 recorded maximum seedling vigour index at highest tolerated level of salinity (Sh) stress condition and N-22, NL-44 and Vyttila -6 showed maximum seedling vigour index at highest tolerated level of temperature stress (Th) stress condition. These nine genotypes were selected for the evaluation of combination stress treatment In the second experiment, The combination stress treatments given were Dh x Sh, Dh x Th, Th x Sh and Dh x Sh x Th. Rice varieties did not germinated at Dh x Sh and Dh x Th. The maximum seedling vigour index at Dh x Sh and combination stress treatment was observed in PTB-7, Vyttila-9, PTB-35 and at Th x Sh was observed in NL-44, MO-18 and N-22 respectively. These rice varieties were selected as tolerant varieties. In experiment III six rice varieties selected from combination stress treatment were evaluated for yield parameters in pot culture experiment. The design of the experiment was CRD with two replications and one control. Drought and salt stress were imposed during reproductive stage for 5 days by applying -5bar PEG6000 and 250mM NaCl solutions respectively into the pots containing rice varieties, Temperature stress was induced using a temperature controlled polyhouse from panicle initiation to maturity stage. Physio-morphological, biochemical and yield parameters were studied under the combination stress treatments. Highest yield under the combination stress treatment of Dh x Sh was observed in PTB-7 and highest yield under the combination stress treatment Th x Sh was observed in N-22. Based on morpho-physiological and yield parameters PTB-7 was selected as the tolerant variety under drought and saline condition and N-22 was selected as the tolerant variety under temperature and salinity condition. In experiment IV all the 20 genotypes were analyzed for the identification of reported markers linked to stress tolerance such as drought salinity and temperature. Reported microsatellite markers linked to drought, salinity and temperature were used to screen 20 rice varieties. Among the markers distinct polymorphism for temperature tolerance between temperature tolerant (N-22 and NL-44) and susceptible varieties was shown by RM 6100. RM 7076 showed distinct polymorphism in tolerant varieties PTB-7 and NL-44 . RM 1287 showed distinct polymorphism for salinity tolerance in PTB-7 and N-22. Drought tolerance between drought tolerant (PTB-7) and susceptible varieties was Shown by RM 490.
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    ThesisItemOpen Access
    Prediction of SSR and SNP markers for anthracnose resiistance in YAM using bioinformatics tools and their validation
    (Department of Plant Biotechnology, College of Agriculture, Vellayani, 2018) Sahla, K; KAU; Sreekumar, J
    The study entitled “Prediction of SSR and SNP markers for anthracnose resistance in yam using bioinformatics tools and their validation” was conducted at ICAR-Central Tuber Crop Research Institute, Sreekariyam, Thiruvananthapuram during October 2107 to August 2018. The objectives of the study is to computationally identify SNPs and SSRs for anthracnose resistance in Greater Yam and the verification of identified markers using resistant and susceptible varieties. The preliminary data set for the identification of SSR and SNP markers was obtained from the EST section of NCBI. A total of 44134 sequences was obtained. The dataset was reduced to 44114 sequences after several pre-processing and screening steps. The resulting sequences were assembled and aligned using CAP3 and 5940 contigs were obtained. SNPs and SSRs were predicted from these datasets using respective prediction tools. The SNP prediction tools such as QualitySNP and AutoSNP were compared for their performance. Analysis was performed to identify the tool with the ability to annotate and identify more viable nonsynonymous and synonymous SNPs. For SSRs the SSR prediction tools such as MISA and SSRIT was compared and analysis was performed to identify the tool having the ability to predict more viable SSRs and the ability to classify them as mono, di, tri, tetra, penta, hexa and poly SSRs. Using QualitySNP, 1789 nonsynonymous SNPs and 73 synonymous SNPs were identified. Using MISA, 359 mono SSRs, 268 di SSRs, 342 tri SSRs, 17 tetra SSRs, 7 penta SSRs, and 9 hexa SSRs were identified. Five sequences from identified SNPs and SSRs which having high hit percentage and low E value were selected for validation and primer designing for anthracnose resistant genes. These primers were validated using 3 resistant and 3 susceptible yam varieties. Among the primers after validation in wet lab, three SNPs (DaSNP1, DaSNP2, DaSNP3) and two SSRs (DaSSR1 and DaSSR2) primer was able to clearly differentiate between the resistant and susceptible varieties which can be used as potential markers in the breeding program for screening anthracnose resistance in yam.