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Open Access
Enhancing carbohydrate and starch accumulation in microalgae for bioethanol production
(Punjab Agricultural University, Ludhiana, 2019) Amanpreet Kaur; Taggar, Monica Sachdeva
The present study was carried out to optimize the culture conditions for enhancing carbohydrate and starch accumulation in Chlorella sorokiniana for the bioethanol production. The growth and biomass of microalgae was studied with the sparging of carbon dioxide into the culture medium. The mean growth (0.70), fresh biomass (7983.33 mg l-1), dry biomass (1516.67 mg l-1) and biomass productivity (163.33 mg l-1 day-1) of microalgae was higher with the sparging of carbon dioxide into the culture medium. The effect of different concentrations of potassium nitrate, i.e. 4, 2 and 1 g l-1 in the culture medium revealed high growth (0.98), fresh (8053.33 mg l-1) and dry biomass (1556.67 mg l-1) of microalgae at 4 g l-1 potassium nitrate in the culture medium. The maximum accumulation of total carbohydrate (50.28%) and starch (34.06%) in the microalgae was observed at 1 g l-1 potassium nitrate concentration in the culture medium at 2 days after culturing (DAC) while the total soluble protein content (18.24%) was observed to be maximum at 4 g l-1 potassium nitrate concentration in the culture medium at 8 DAC. The maximum chlorophyll a, b and total chlorophyll content of 403.22 μg g-1 fw, 346.66 μg g-1 fw and 749.88 μg g-1 fw of microalgae was observed at 4 g l-1 potassium nitrate level in the culture medium, respectively. Morphological characterization of C. sorokiniana revealed dense starch granules in the cells under nitrogen limiting conditions. Chitosan, at a concentration of 200 ppm, showed maximum flocculation (90.94%) of microalgal suspension after 60 min. Pre-treatment of microalgal biomass with 1 N sulphuric acid revealed maximum production of total (487.41 mg g-1) and reducing sugars (277.56 mg g-1). The fermentation of microalgal hydrolysate by Saccharomyces cerevisiae resulted in maximum ethanol content and yield of 0.52 g and 0.052 g g-1 biomass at 96 h of fermentation.
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Evaluation of magnetic nanoparticle immobilized cellulases for enzymatic saccharification of rice straw
(Punjab Agricultural University, Ludhiana, 2019) Prabhpreet Kaur; Taggar, Monica Sachdeva
The present study was conducted to evaluate the efficiency of magnetic nanoparticle immobilized cellulases for enzymatic saccharification of rice straw. The optimization studies for cellulase production by A. fumigatus under solid state fermentation conditions revealed that the maximum cellulase production (filter paper activity of 486.09 nmol min-1g-1ds, CMCase activity of 2482.33 nmol min-1g-1ds, cellobiase activity of 1911.13 nmol min-1g-1ds and xylanase activity of 8.90 μmol min-1g-1ds) was recorded with mixture of rice straw and soybean pod husk as carbon source and urea as nitrogen source with optimum inoculum concentration of 107 spores ml-1 after 96 h of incubation. The temperature of 40°C and pH of production media at 5.5 was optimum for maximum cellulase production. The cellulase was, then, immobilized onto magnetic nanoparticles with binding efficiency of 65.55 per cent. The characterization studies using SEM showed rough surface topography and agglomeration of nanoparticles upon cellulase immobilization. SEM-EDS studies depicted increase in carbon and oxygen elemental composition and TEM micrographs showed an increase in mean diameter of cellulase immobilized nanoparticles. FTIR spectra showed a characteristic peak at 1390 cm-1 after immobilization of cellulase onto magnetic nanoparticles. Characterization studies revealed that the optimum temperature and pH of immobilized enzyme was 60°C and 5.0, respectively and it retained 56.87 per cent of its maximal activity after 6 h of preincubation at 60°C. The Km value for immobilized enzyme (11.76 mM) was slightly higher than that of free enzyme (10.52 mM). The saccharification of sequential acid autoclave-alkali pre-treated rice straw using free and immobilized cellulase resulted in 462.27 and 456.75 mg g-1 reducing sugars, respectively at 72h of incubation. The saccharification efficiency of 53.30 and 52.67 per cent was achieved with free and immobilized cellulase, respectively.
Open Access
Relating tuber dormancy length with antioxidants and low-temperature sweetening (LTS) in potato cultivars
(Punjab Agricultural University, Ludhiana, 2019) Gupta, Himani; Zhawar, Vikramjit Kaur
Work of relating tuber dormancy with low temperature sweetening (LTS)-resistance and tuber antioxidant content was done in eleven potato cultivars varying in LTS-resistance during cold storage. This work showed that dormancy can be positively related to LTS-resistance where LTS resistance could involve sucrose/starch metabolism oriented more towards anabolism than catabolism, thus beneficial for both dormancy and LTS-resistance. This was seen the best in Lady Rosetta followed by Kufri Frysona and MP/04 578. However vacuolar invertase activity was positively related to hexogenesis in LTS-susceptible cultivars only as LTSresistant cultivars also increased activity of this enzyme upon cold storage, thus enzyme may also be playing other important role during tuber storage. Lady Rosetta was found more dormant at room temperature as well as under cold storage but MP/04 578 and Kufri Frysona were less dormant at room temperature but became more dormant during cold storage. For antioxidant content, Lady Rosetta was found to increase antioxidant content specially catalase with increasing pace of ROS specially H2O2 but other cultivars were poor in this response, thus end up with increasing oxidative toxicity during cold storage. Tubers of Lady Rosetta were found more uniform for size, dormancy related parameters and less effected by seasonal environmental changes during crop growth and storage compared to other cultivars which showed wide variations. This study showed that tuber dormancy can be positively related to LTS-resistance and antioxidant content.
Open Access
Evaluation of elicitor treatment on biochemical changes in cotton seedlings subjected to high temperature stress
(Punjab Agricultural University, Ludhiana, 2019) Hunjan, Harsimran; Sangha, Manjeet Kaur
In the present study effect of elicitors; salicylic acid (SA, 50 ppm), calcium chloride (CaCl2, 50ppm), gibberellic acid (GA3, 5ppm) and succinic acid (100ppm recommended by PAU) on heat stress amelioration in seven day old cotton seedlings (Gossypium hirsutum - LH 2298 and LH 2076; Gossypium arboreum - LD 949 and LD 1019) was evaluated in terms of changes in morphophysiological, carbohydrate and protein status and oxidative and antioxidant parameters. High temperature (HT) stresswas given for 1 hr at 40, 45, 50 and 55°C to seven day old cotton seedlings. Seedlings of LH2298, LD949 depicted 50% survival at 55°C followed by LH 2076 (43%) and LD 1019 (41%). HT stress decreased the root and shoot length in seedling which got revived after recovery. Loss of moisture increased with increase in stress temperature. The chlorophyll content decreased from 26-37% with maximum decrease in LD 949. LH 2298 control had highest total carbohydrates, which were negatively affected by HT. The soluble sugars and soluble proteins registered increase. HT stress inceased electrolyte leakage, H2O2 as well as MDA content to minimum in LH 2298 and LD 949. Maximum increase in SOD, POD, APX and GR activity was seen in LH 2298 and LD949 whereas CAT activity declined after HT exposure. Proline, phenolics, ascorbic acid, tocopherols and carotenoids also depicted increase. Seed priming treatment with SA@50ppm was most effective in decreasing the negative effect of HT in terms of improving various estimated parameters in seven day old cotton seedlings, followed by treatment with CaCl2, succinic acid and GA. SA effect was demonstrated maximum in LH 2298 and LD 949. Priming treatment was more effective than seedling spray. In conclusion the given cotton genotypes showed heat tolerance with the order of tolerance as LH 2298>LD 949>LH 2076>LD 1019 and among the elicitors used, SA priming ameliorated the heat stress to maximum. The various parameters in cotton genotypes showed differential response towards heat stress.
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Biochemical evaluation of interspecific lines of mungbean (Vigna radiata L. Wilczek)
(Punjab Agricultural University, Ludhiana, 2019) Jain, Vritika; Sharma, Sucheta
The present investigation reports physicochemical parameters, proximate composition, nutrient and antinutrient components in 7 mungbean x ricebean interspecific lines, 13 mungbean x urdbean interspecific lines and 5 check varieties. These genotypes exhibited 100-seed fresh weight, 100-seed dry weight, seed volume, seed density, water absorption capacity, volume expansion, swelling capacity, swelling index, hydration capacity and hydration index in the range of 3.34-5.13 g, 2.92-4.64 g, 0.03-0.06 ml, 0.77-1.39 g/ml, 120.5-174.1, 200-527.8%, 0.10-0.16 ml/seed, 0.66-0.84, 0.05-0.08 g/seed and 1.21-1.74, respectively. Interspecific lines exhibited lower mean seed volume and swelling index but higher mean values for seed density, volume expansion and swelling capacity per seed as compared to check varieties. Interspecific lines contained 7.86-12.09% moisture content, 19.48-24.97% crude protein, 18.4-50.8% NDF, 7.0-11.4% ADF and 0.55-2.25% ADL. P, K, Mg, Ca, Fe, Mn, Zn and Cu content among the interspecific lines ranged from 280.0-334.8, 488.4-1401.2, 86.0-203.5, 67.6-201.6, 2.59-5.51, 0.50-0.82, 2.13-3.32 and 0.71-3.02 mg/100g, respectively. SML 1808 exhibited the highest content of total soluble sugars (328.44 mg/g) while SML 2011 exhibited the lowest (30.65 mg/g). Mean values of reducing sugars, non-reducing sugars, sucrose, starch, amylose and amylopectin in these lines were 3.62, 111.21, 26.34, 329.50, 163.24 and 166.23 mg/100g, respectively. Total soluble proteins, free amino acids, methionine, cysteine and tryptophan contents varied from 177.2-230.3, 0.84-2.63, 3.21-7.10, 0.08-0.15 and 0.67-1.32 mg/g, respectively. Protein fractionation studies revealed 32.6-48.3 (albumins), 153.3-218.8 (globulins), 2.81-8.30 (prolamins) and 22.22-66.23 mg/g seed (glutelins). Electrophoretic studies of the total proteins revealed presence of 6-11 bands with molecular weights of approximately 13-162 kDa. Interspecific lines contained 1.96-2.54 mg/g phytate, 2.41-3.81 mg/g total phenols, 0.66-2.18 mg/g tannins, 120-2560 HU/g lectins, 7.50-23.46 TIU/mg trypsin inhibitor and 48.87-61.47 AIU/g amylase inhibitor activities. SML 1809 was rich in carbohydrates, total phenolics and tannins but exhibited low protein content. SML 1820, SML 1827 and SML 2034 lines exhibited low phytic acid and trypsin inhibitor activity and more proteins and sugar contents. SML 2031 and SML 2032 (mungbean x ricebean lines) and SML 1817, SML 2033 and SML 2034 (mungbean x urdbean lines) were better in terms of their nutritional composition. Overall, SML 2033 was found to be a nutritionally promising line as it exhibited highest 100-seed weight and hydration capacity with high amounts of cysteine, methionine, tryptophan, globulins, iron and manganese.
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Antioxidative defense mechanism in wild and cultivated chickpea cultivars against Helicoverpa armigera infestation
(Punjab Agricultural University, Ludhiana, 2019) Harpreet Singh; Grewal, Satvir Kaur
The present study was undertaken to study the biochemical response in leaves, pod wall and seeds of three wild (GLW 22, GLW 58 and GLW 187) and five desi (GL 12021, GL 29095, GL 29078, H11 22 and CSJ 515) chickpea genotypes by comparing them with two checks (resistant check ICCL 86111 and susceptible check ICC 3137) against Helicoverpa armigera infestation. Superoxide dismutase activity significantly increased in leaves of resistant check ICCL 86111 after infestation. Catalase and peroxidase activities increased in leaves of GLW 58, GL 12021, GL 29095 and GL 29078 and ascorbate peroxidase-glutathione reductase activities increased in leaves of GLW 58 after infestation as compared to resistant check. Higher activities of superoxide dismutase, catalase and peroxidase was observed in podwall of GLW 187 and GL 29078. Higher proline content in leaves of GL 29078; in podwall of GLW 22, GL 12021 and H11 22 and in seeds of GLW 187, H11 22 and GL 29078 after infestation might be due to the enhanced activities of proline biosynthetic enzymes in them. Higher activities of polyphenol oxidase in leaves of GLW 22 and GL 29095 as well as enhanced activities of phenylalanine ammonia lyase was observed in leaves of all the genotypes as compared to resistant check ICCL 86111. MDA content decreased in leaves, podwall and seeds of GLW 187 and GL 12021 after infestation. Higher flavanol and total phenol content was observed in leaves of GLW 22, GLW 187, H11 22 and GL 29078 after infestation. Lower percent pod damage (9.58-12.44%) in GL 12021, GL 29095, H11 22, GLW 22, GL 29078, GLW 187 as compared to pod damage in resistant check (16.18%) and susceptible check (21.50%) might be attributed to differential induced defense mechanism in them.
Open Access
Comparative studies of carbohydrate metabolism in normal, sweet corn and quality protein maize
(Punjab Agricultural University, Ludhiana, 2019) Sanjeev Kumar; Chaudhary, Dharampaul
Maize is one of the world‟s most important cereal and occupies third rank after rice and wheat. Carbohydrates such as sugars (sucrose, glucose, maltose and sorbitol) and starch are the major nutritional component of the major kernel. Sweet corn varieties accumulate high sugars content due to presence of mutants like sh, su etc. Although the biochemical effect of these mutants is well understood but time course evaluation of kernel carbohydrates and enzyme under different genetic background was not known. Present study focused on the temporal profiling of carbohydrate metabolites and key enzymes in normal, sweet corn and QPM lines at three stages (15, 30 and 45 DAP) of kernel development. The result revealed that free sugars decreases, whereas, starch content increases with kernel development. However, sweet corn retained maximum sugars and minimum starch as compared to normal and QPM counterparts at all the stages of kernel development. The rate of sugars catabolism was fast indicating that a narrow window exist for kernel sweetness in sweet corn. The key enzyme of carbohydrate metabolism including invertase, hexokinase and sucrose synthase are retained maximum in sweet corn as compared to their normal and QPM counterparts at 30 and 45 DAP. No significant variation was observed within genotypes of any maize type for the above parameters studied. However, some normal and QPM lines having numerically superior vales of free sugars have been identified which can be further evaluated for developing comparatively sweet normal and QPM varieties.
Open Access
Biochemical basis of leaf blight resistance in barley (Hordeum vulgare L.)
(Punjab Agricultural University, Ludhiana, 2019) Simardeep Kaur; Bhardwaj, Rachana D.
In the present investigation, leaves of six barley genotypes namely PL 807, BH 946, DWRUB 52, BL 1338, BL 1369 and PL 426 inoculated with Bipolaris sorokiniana were evaluated for antioxidant potential, levels of H2O2, MDA, antioxidative enzymes, non-enzymatic antioxidants, pathogenesis- related (PR) proteins and β-glucan. The disease severity was assessed at two different stages viz. GS 55 and GS 87 during 2017-18 and 2018-19. The genotype BL 1369 showed moderately resistant, PL 807 and BL 1338 moderately susceptible and the other genotypes demonstrated susceptible behavior after fungal infection. On fungal inoculation, an increase in total phenols, flavonoids, carotenoids along with the free radical scavenging activities (DPPH, NO, FRAP) was reported in BL1369 and BL 1338 during GS 55 stage whereas, in PL 807 and PL 426, decrease of DPPH. and NO. scavenging capacities and total phenols was observed. During GS 87 stage, maximum increase of catalase, ascorbate peroxidase, glutathione reductase, phenylalanine ammonia lyase, tyrosine ammonia lyase and polyphenol oxidase activities alongwith concomitant decrease of H2O2 content in the infected lower leaves of BL 1369 could be responsible for its moderately resistant behaviour. Although on fungal inoculation, chitinase activity increased in all the genotypes except DWRUB 52 and BL 1338 but maximum increase was reported in BL 1369. β-glucanase activity also increased significantly in all the leaf tissues of BL 1369. The β-glucan content decreased in DWRUB 52 and PL 426 upon fungal infection while it increased in BL 1338 and BL 1369.
Open Access
Evaluation of vacuolar ATPase and identification of salt stress responsive genes in cotton
(Punjab Agricultural University, Ludhiana, 2019) Charandeep Singh; Sangha, Manjeet Kaur
The present study evaluated the effect of salinity stress on various ATPase activities i.e vacuolar (V)-ATPase, F-ATPase and plasma (P)-ATPase in salt tolerant (LH 2108 (Gossypium hirsutum) and LD 949 (G.arboreum)) and salt susceptible (F1378, F2228 (G. hirsutum) and FDK124 (G.arboreum)) cotton genotypes. The seeds were grown in pots at salinity levels of 9, 15 and 18 dS/m. The leaf and root samples were collected at 15 and 30 days after germination. In response to salinity the V-ATPase activity registered maximum increase followed by F-ATPase, while P-ATPase registered decline. LH2108 (G. hirsutum) showed maximum increase in V-ATPase and F ATPase activities followed by that in LD 949 (G.arboreum). LH 2108 (G.hirsutum), registered 27.05 to 35.26μmol Pi formed h-1 mg-1 protein increase in mean leaf V-ATPase activity followed by that in LD 949 (G. arboreum) (27.30 to 34.25 μmol Pi formed h-1 mg-1 protein) from control to 18EC. Similar trend was observed for root samples and for protein content in leaf and root tissues. Genes (19) of salinity tolerance pathways viz. SOS4, HKT, HDG, GhPLATZ, SCARECROW, ABR1, GbRLK1, WRKY33, lysophospholipase, β-ketoacyl CoA synthase, ROS scavenging activity including GhSOD1, udp glucosyltransferase, GhMT3a, GhAnn1, ZAT10, WRKY39-1, osmolytic regulation P5CS, sucrose phosphate synthase, sorbitol dehydrogenase and trehalose synthase, selected by in silico analysis, showed their presence (by PCR amplification) in the selected (19) cotton genotypes. The salt tolerant G.hirsutum genotype showed better salinity tolerance which might be due to higher V and F-ATPase activities and also might be due to the presence of the selective salinity stress responsive genes.

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