Altaf Ahmad

Changes in growth, lipid peroxidation and some key antioxidant enzymes in chickpea genotypes under salt stress

The present study was conducted to evaluate the effect of NaCl on growth and some key antioxidants in chickpea. Eight genotypes of chickpea were grown hydroponically for 15xa0days and then treated with different concentrations of salt [0xa0mM (T0), 25xa0mM (T1), 50xa0mM (T2), 75xa0mM (T3), and 100xa0mM (T4)]. Salinity showed marked changes in growth parameters (fresh and dry weight of root and shoot). The level of lipid peroxidation was measured by estimating malondialdehyde content. Lipid peroxidation increases with the increase in NaCl concentration in all genotypes but salt-tolerant genotypes (SKUA-06 and SKUA-07) were least affected as compared to other genotypes. The chlorophyll content was also affected with elevated levels of NaCl. Increased concentration of salt increased the activity of antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase in all chickpea genotypes but maximum activity was observed in salt-tolerant (SKUA-06 and SKUA-07) genotypes. Two genotypes of salt-tolerant and salt-sensitive varieties were analyzed further by real time PCR which revealed that the expression of SOD, APX and CAT genes were increased by NaCl in the salt-tolerant variety. The enhancement in tolerance against salt stress indicates that the genes involved in the antioxidative process are triggered by oxidative stress induced by environmental change. The results indicate that NaCl-induced oxidative stress hampers the normal functioning of the cell. The efficient antioxidants play a great role in mitigating the effect of NaCl stress in chickpea. This screening of NaCl-tolerant genotypes of chickpea can be performed on salt-affected land.

Validated HPTLC analysis method for quantification of variability in content of curcumin in Curcuma longa L (turmeric) collected from different geographical region of India

Abstract Objective To develop a simple, sensitive, precise, and accurate stability-indicating high performance thin-layer chromatographic method for analysis of curcumin (the main active constituent of turmeric). Methods The separation was achieved on TLC aluminum plates precoated with silica gel 60F 254 using toluene-chloroform-methanol (5:4:1, v/v/v) as a mobile phase. Densitometric analysis was performed at 430 nm. Results This system was found to have compact spot of curcumin at RF value of (0.31±0.02). For the proposed procedure, linearity (r2 = 0.99354 ± 0.00120), limit of detection (50 ng/spot), limit of quantification (200 ng/spot), recovery (ranging from 98.35% – 100.68%), and precision (⩽2.25%) were found to be satisfactory. Statistical analysis reveals that the content of curcumin in different geographical region varied significantly. Conclusions The highest and lowest concentration of curcumin in Turmeric was found to be present in sample of Erode (Tamilnadu) and Surat (Gujrat) respectively which inferred that the variety of turmeric found in Erode (Tamilnadu) is much superior to other region of India.

Chromium-Induced Modulation in the Antioxidant Defense System During Phenological Growth Stages of Indian Mustard

Chromium-induced modulation in the enzymes and metabolites of antioxidants was investigated at various phenological stages of Indian mustard (Brassica juncea (L.) Czern. & Coss. cv Pusa Jai Kisan)], grown with various levels of chromium (Cr) in pots under natural environmental conditions. Chromium accumulation in the root, stem and leaves increased with the advancement in the age of the plants. Growth of Indian mustard was not affected significantly by the supply of Cr upto the levels of 400 mg kg−1 soil. Activities of superoxide dismutase (SOD), ascorbate peroxide (APX), catalase (CAT), and glutathione reductase (GR) increased in the leaves of Cr-treated plants, when compared with control. High activities of antioxidant enzymes supported by high Cr concentrations in roots and aerial parts (except seeds) established the Indian mustard as a potential hyperaccumulator and a hypertolerant species to Cr stress. For this study, an edible crop was chosen intentionally so as to tap maximum benefit by remediating the contaminated site on one hand and getting uncontaminated seeds to raise the next generation, on the other.

Variability in Indian bread wheat (Triticum aestivum L.) varieties differing in nitrogen efficiency as assessed by microsatellite markers

Wheat (Triticum aestivum L.) is a staple food for half of the world. Its productivity and agronomical practices, especially for nitrogen supplementation, is governed by the nitrogen efficiency (NE) of the genotypes. We analyzed 16 popular cultivated Indian varieties of wheat for their NE and variability estimates using a set of 21 simple sequence repeat (SSR) markers, derived from each wheat chromosome. These genotypes were categorized into three groups, viz., low, moderate, and high nitrogen efficient. Of these 16 genotypes, we have reported six, eight, and two genotypes in high, moderate, and low NE categories, respectively. The differential NE in these genotypes was supported by nitrogen uptake and assimilation parameters. The values of average polymorphic information content and marker index for these SSR markers were estimated to be 0.32 and 0.59, respectively. The genetic similarity coefficient for all possible pairs of varieties ranged from 0.41 to 0.76, indicating the presence of considerable range of genetic diversity at molecular level. The dendrogram prepared on the basis of unweighted pair-group method of arithmetic average algorithm grouped the 16 wheat varieties into three major clusters. The clustering was strongly supported by high bootstrap values. The distribution of the varieties in different clusters and subclusters appeared to be related to their variability in NE parameter that was scored. Genetically diverse parents were identified that could potentially be used for their desirable characteristics in breeding programs for improvement of NE in wheat.

Genetic diversity analysis of Zingiber Officinale Roscoe by RAPD collected from subcontinent of India

The present investigation was undertaken for the assessment of 12 accessions of Zingiber officinale Rosc. collected from subcontinent of India by RAPD markers. DNA was isolated using CTAB method. Thirteen out of twenty primers screened were informative and produced 275 amplification products, among which 261 products (94.90%) were found to be polymorphic. The percentage polymorphism of all 12 accessions ranged from 88.23% to 100%. Most of the RAPD markers studied showed different levels of genetic polymorphism. The data of 275 RAPD bands were used to generate Jaccards similarity coefficients and to construct a dendrogram by means of UPGMA. Results showed that ginger undergoes genetic variation due to a wide range of ecological conditions. This investigation was an understanding of genetic variation within the accessions. It will also provide an important input into determining resourceful management strategies and help to breeders for ginger improvement program.

Global Climate Change, Stress and Plant Productivity

Global climate change, rated as the most serious threat to the environment, has been the center of debate among environmentalists and policy makers as it has become not only an environmental, a political and an economic issue, but also a global problem, of which agriculture is the major target. At the plant or field scale, climate change is likely to interact with rising CO2 concentrations and other environmental changes such as temperature, precipitation (associated with changes in tropo-, as well as stratospheric ozone levels) and UV-B radiation to affect crop physiology. The present chapter reviews the potential changes in plant physiological processes caused by these factors.

Salt stress-induced modulations in the shoot proteome of Brassica juncea genotypes.

Indian mustard [Brassica juncea (L.) Czern and Coss] is cultivated mainly in the northwestern agroclimatic region of India and suffers huge losses in productivity due to salinization. In an effort to figure out adaptation strategies of Indian mustard to salt stress, we conducted a comparative proteome analysis of shoots of its two genotypes, with contrasting sensitivity to salt stress. Differential expression of 21 proteins was observed during the two-dimensional electrophoresis (2DE). The identified salt-stress-responsive proteins were associated with different functional processes including osmoregulation, photosynthesis, carbohydrate metabolism, ion homeostasis, protein synthesis and stabilization, energy metabolism, and antioxidant defense system. Salt-tolerant genotype (CS-52) showed a relatively higher expression of proteins involved in turgor regulation, stabilization of photosystems and proteins, and salt compartmentalization, as compared to salt-sensitive genotype (Pusa Varuna). Our results suggest that modulating the expression of salt-responsive proteins can pave the way for developing salt tolerance in the Indian mustard plants.

Uptake-related parameters as indices of phytoremediation potential

Phytoremediation is emerging as an alternative agriculture-based technology because remediation of metalpolluted sites can be brought about utilizing the ability of plants to uptake and store contaminants in them. A field study was conducted to assess the role of Indian mustard in phytoremediation of chromium-contaminated substrata. Uptake parameters, namely, bio-concentration factor, translocation index, Cr distribution within plant, and tolerance index were used in determining the remediation potential of the crop. A significant increase in Cr accumulation (0.64–4.19 mg g−1 DW, stem; and 0.77–1.1 mg Cr g−1 DW, root), coupled with high tolerance indices, was observed in response to Cr stress, thus showing that Indian mustard is a potential hyperaccumulator. Movement and subsequent distribution of metal ions in the plant were assessed by studying the translocation index which showed a consistent increase (27–87% at T5) with time, and bioconcentration factor, where also an increase over a time period was observed in stem (1.3–11.4, T1) and root (1.96–5.56, T1), thereby, depicting the strong ability of Indian mustard for phytoextraction. A significant decline, however, was observed in the bioconcentration factor with increase in the dose of Cr application.

RAPD Markers Associated with Salt Tolerance in Soybean Genotypes Under Salt Stress

In order to investigate the influence of genetic background on salt tolerance in soybean (Glycine max), ten soybean genotypes (Pusa-20, Pusa-40, Pusa-37, Pusa-16, Pusa-24, Pusa-22, BRAGG, PK-416, PK-1042, and DS-9712) released in India, were selected and grown hydroponically. The 10-day-old seedlings were subjected to 0, 25, 50, 75, 100, 125, and 150xa0mM NaCl for 15xa0days. Plant growth, leaf osmotic adjustment, and random amplified polymorphic DNA (RAPD) analysis were studied. In comparison to control plants, the plant growth in all genotypes was decreased by salt stress, respectively. Salt stress decreased leaf osmotic potential in all genotypes; however, the maximum reduction was observed in genotype Pusa-24 followed by PK-416 and Pusa-20, while minimum reduction was shown by genotype Pusa-37, followed by BRAGG and PK-1042. Pusa-16, Pusa-22, Pusa-40, and DS-9712 were able to tolerate NaCl treatment up to the level of 75xa0Mm. The difference in osmotic adjustment between all the genotypes was correlated with the concentrations of ion examined such as Na+ and the leaf proline concentration. These results suggest that the genotypic variation for salt tolerance can be partially accounted by plant physiological measures. Twenty RAPD primers revealed high polymorphism and genetic variation among ten soybean genotypes studied. The closer varieties in the cluster behaved similarly in their response to salinity tolerance. Intra-clustering within the two clusters precisely grouped the ten genotypes in sub-cluster as expected from their physiological findings. Our study shows that RAPD technique is a sensitive, precise, and efficient tool for genomic analysis in soybean genotypes.

Determination of Curcuminoids in Curcuma longa Linn. by UPLC/Q-TOF-MS: An Application in Turmeric Cultivation.

Cucuma longa Linn. (Fam-Zingiberaceae) is a valued medicinal plant contains curcuminoids (curcumin, demethoxycurcumin and bisdemethoxycurcumin) as major bioactive constituents. Previously reported analytical methods for analysis of curcuminoids were found to suffer from low resolution, lower sensitivity and longer analytical times. In this study, a rapid, sensitive, selective high-throughput ultra high performance liquid chromatography-tandem mass spectrometry (UPLC/Q-TOF-MS) method was developed and validated for the quantification of curcuminoids with an aim to reduce analysis time and enhance efficiency. UPLC/Q-TOF-MS analysis showed large variation (1.408-5.027% w/w) of curcuminoids among different samples with respect to their occurrence of metabolite and their concentration. The results showed that Erode (south province) contains highest quantity of curcuminoids and concluded to be the superior varieties. The results obtained here could be valuable for devising strategies for cultivating this medicinal plant.