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  • ThesisItemOpen Access
    (2015-09) BHADANIA ROSHANI ASHWINBHAI; Golakiya B. A.
    Key words: salt tolerant endophytic bacteria, PGPB, 16s rRNA amplification, GFP, WGS. The importance of plant growth promoting rhizobacteria in growth promotion and their ability to elicit ‘induced systemic tolerance’ against abiotic stresses has been well documented. In this study, out of a seventy two bacterial isolated from the tissues of four Malvaceae family plant grown under saline environment collected from Kutch, Gujarat, through screening seventeen were selected to be highly salt-tolerant up to 12.5% NaCl and identified and characterized them using morphological, biochemical and molecular traits. All seventeen isolates were able to reduced nitrate and none were positive for phenylalanine deaminase. Fifteen isolates gave positive result for urease activity while twele isolates produce H2S gas and dextrose sugar. Eleven isolates gave positive results for arginine, ornithrine, glucose, fructose and galactose test. Five isolates were positive for proline test. Ten isolates were able to fermate lactose, arabinose, sucrose and maltose sugar. The nine isolates were positive for xylose, while eight isolates were for sorbitol and cellobiose. The six isolates gave a positive outcome for citrate utilization and fermentation of raffinose and inositol sugar, where five isolates gave positive results for lysine and proline utilization and also maltose sugar. The four showed positive for phosphate solubilization, while eleven were able to produce siderophore. Ten isolates positive for protease activity and all were positive for ACC deaminase production in which AIK35 gave highly ACC deaminase activity which is directly affected to salt tolerance. All 17 isolates able to produced IAA and EPS. The promising isolates AIK35 and WC68 showed IAA production were 7.51 and 66.73 μgml-1 at 12.5% NaCl concentration and also gave highly IAA in normal broth. Where AIK35, AIB49, AIB52 and WC68 showed EPS production were 129.67, 180.76, 164.36 and 90.15 μgml-1 at 12.5% NaCl concentration. The isolates AIK35, AIB49, AIB52 and WC68 showed good antagonism towards growth of Fusarium oxysporum and Rhizoctonia Solani. Based on 16s rRNA analysis isolates, AIK35, AIB49, AIB52 and WC68 were identified as a Providencia rettgeri strain NCTC 11801, Microvirga zambiensis strain WSM3693, Providencia vermicola strain OP1 and Alcaligenes faecalis strain NBRC 13111, respectively. In vivo tests, the bacterial combination Providencia vermicola strain OP1, Alcaligenes faecalis strain NBRC 13111 and Providencia rettgeri strain NCTC 11801 were applied as an aqueous suspension to the rhizosphere was found most effective in enhancing growth of the cotton plant in soil having 2.5 EC NaCl concentration as compare to normal soil (0.4EC) after three month of plant emergence followed by Microvirga zambiensis strain WSM3693, Providencia vermicola strain OP1 and Alcaligenes faecalis strain NBRC 13111combination. The four efficient isolates AIK35, AIB49, AIB52 and WC68 were successfully GFP-tagged with pGLO plasmid. Bacteria were successfully colonized all parts (roots, stem and leaves) of cotton plant observed by fluorescent microscopic. The screened best isolate AIK35 was Gram negative cocco bacilli observed by scanning electron microscope. Based on screened best isolate Providencia rettgeri MR4 (AIK35) having genome size 3.2 Mb pusing whole genome sequencing. The present research support salt tolerant endophytic activity towards cotton growth. The performance of this bacterium under saline conditions will be of great importance in the current agricultural scenario.
  • ThesisItemOpen Access
    (2014-10) SANGHANI ATUL ODHAVJIBHAI; Golakiya B. A.
    Key words: Linkage, QTL, DMR, Linkage group, SSR, LOD. Present experiment on “LINKAGE AND QTL MAPPING FOR DOWNY MILDEW RESISTANCE IN PEARL MILLET (Pennisetum glaucum (L.) R. Br.)” was conducted at Department of Biotechnology, Junagadh Agricultural University, Junagadh, The study was formulated to improve the yield potential of hybrids of J-2372, which is one of the elite and important restorer lines used in hybrid breeding programs in Gujarat. Identification of downy mildew resistance genomic regions was set as an objective. Downy mildew of pearl millet is one of the most important devastating diseases limiting pearl millet productivity. DNA-based marker tools facilitated better understanding of the inheritance and expression of downy mildew. To fulfill the objectives, the two pearl millet inbred parental lines were crossed to F1, and the F1 progenies were selfed to produced 125 segregating F2 mapping population progenies for generating marker data using 24 SSR out of 80 markers exhibiting clear polymorphism between parental lines. The downy mildew screening of segregating F2 population progenies based on J-2480 x J-2372 against downy mildew was done at JAU., Jamnagar. R QTL interval mapping method identified two downy mildew QTLs on Linkage Group 1 and Linkage Group 6. This best single-QTL model detected by interval mapping on Linkage Group 1 (M1 marker) recorded a high LOD score of 6.3 with map position 14.8 and explained 46.4 % of recorded phenotypic variation in downy mildew incidence among 125 F2 progenies and Linkage Group 6 (M44 marker) recorded a LOD score of 1.6 with map position 56.07 and explained 36 % of recorded phenotypic variation in downy mildew incidence among 125 F2 progenies against Sclerospora graminicola pathogen The confidence interval detected that the position between 10-15 cM on linkage group 1 was responsible for the resistance against downy mildew in pearl millet. The effect plot for marker M1 indicated that the resistance against the downy mildew was governed by dominant inheritance and can be easily used for the transfer of trait though marker assisted selected using marker M1. In present study, downy mildew resistance QTLs detected exhibited over-dominant modes of inheritance, and DMR resistant QTLs come from resistant male parent J-2480. These identified DMR QTLs from J-2480 can now be transferred to genetic backgrounds of elite pearl millet hybrid parental lines (J-2372) through marker-assisted backcrossing programs. Flanking markers of the identified QTLs can facilitate selection of resistant progenies during the backcrossing process, where as other marker loci can be used in reducing the length of the donor segments carried along with the introgressed DM resistance genes and/or selecting for recovery of recurrent parent alleles on non-carrier chromosomes.