Comparative transcriptome analyses revealed different heat stress responses in pigeonpea (Cajanus cajan) and its crop wild relatives.

KEY MESSAGE: Comparative transcriptome analyses accompanied by biochemical assays revealed high variability in heat stress response in Cajanus species. Among the studied species, C. scarabaeoides was the most thermotolerant followed by C. cajanifolius, C. cajan, and C. acutifolius. Pigeonpea is one of the climate-resilient grain legumes. Though the optimum temperature for cultivated pigeonpea is ~ 25-35 °C, its wild relatives grow in temperatures ranging between 18 and 45 °C. To gain insight into molecular mechanisms responsible for the heat stress tolerance in pigeonpea, we conducted time-series transcriptome analysis of one pigeonpea cultivar (Cajanus cajan) and two wild relatives, Cajanus acutifolius, and Cajanus scarabaeoides subjected to heat stress at 42 ± 2 ºC for 30 min and 3 h. A total of 9521, 12,447, and 5282 identified transcripts were differentially expressed in C. cajan, C. acutifolius, and C. scarabaeoides, respectively. In this study, we observed that a significant number of genes undergo alternative splicing in a species-specific pattern during heat stress. Gene expression profiling analysis, histochemical assay, chlorophyll content, and electrolyte leakage assay showed that C. scarabaeoides has adaptive features for heat stress tolerance. The gene set enrichment analyses of differentially expressed genes in these Cajanus species during heat stress revealed that oxidoreductase activity, transcription factor activity, oxygen-evolving complex, photosystem-II, thylakoid, phenylpropanoid biosynthetic process, secondary metabolic process, and flavonoid biosynthetic process were highly affected. The histochemical assay showed more lipid peroxidation in C. acutifolius compared to other Cajanus species inferring the presence of higher quantities of polyunsaturated fatty acids in the plasma membrane which might have led to severe damage of membrane-bound organelles like chloroplast, and high electrolyte leakage during heat stress. This study paves the way for the identification of candidate genes, which can be useful for the development of thermo-tolerant pigeonpea cultivars.

Identification and characterization of Dicer-like genes in leaf rust pathogen (Puccinia triticina) of wheat.

Puccinia triticina (P. triticina) is one of the most devastating fungal pathogens of wheat which causes significant annual yield loss to the crop. Understanding the gene regulatory mechanism of the biotrophic pathogen is one of the important aspects of host-pathogen interaction studies. Dicer-like genes are considered as important mediators of RNAi-based gene regulation. In this study, we report the presence of three Dicer-like genes (Pt-DCL1, Pt-DCL2, Pt-DCL3) in P. triticina genome identified through computational and biological analyses. Quantitative real-time PCR studies revealed an increase in the expression of these genes in germinating spore stages. Heterologous expression combined with mass spectrometry analysis of Pt-DCL2 confirmed the presence of a canonical Dicer-like gene in P. triticina. Phylogenetic analysis of the Pt-DCLs with the Dicer-like proteins from other organisms showed a distinct cluster of rust pathogens from the order Pucciniales. The results indicated a species-specific duplication of Dicer-like genes within the wheat rust pathogens. This study, for the first time, reports the presence of Dicer-dependent RNAi pathway in P. triticina that may play a role in gene regulatory mechanism of the pathogen during its development. Our study serves as a vital source of information for further RNAi-based molecular studies for better understanding and management of the wheat leaf rust disease.

Transcriptome profiling of differentially expressed genes in cytoplasmic male-sterile line and its fertility restorer line in pigeon pea (Cajanus cajan L.).

BACKGROUND: Pigeon pea (Cajanus cajan L.) is the sixth major legume crop widely cultivated in the Indian sub-continent, Africa, and South-east Asia. Cytoplasmic male-sterility (CMS) is the incompetence of flowering plants to produce viable pollens during anther development. CMS has been extensively utilized for commercial hybrid seeds production in pigeon pea. However, the molecular basis governing CMS in pigeon pea remains unclear and undetermined. In this study transcriptome analysis for exploring differentially expressed genes (DEGs) between cytoplasmic male-sterile line (AKCMS11) and its fertility restorer line (AKPR303) was performed using Illumina paired-end sequencing. RESULTS: A total of 3167 DEGs were identified, of which 1432 were up-regulated and 1390 were down-regulated in AKCMS11 in comparison to AKPR303. By querying, all the 3167 DEGs against TAIR database, 34 pigeon pea homologous genes were identified, few involved in pollen development (EMS1, MS1, ARF17) and encoding MYB and bHLH transcription factors with lower expression in the sterile buds, implying their possible role in pollen sterility. Many of these DEGs implicated in carbon metabolism, tricarboxylic acid cycle (TCA), oxidative phosphorylation and elimination of reactive oxygen species (ROS) showed reduced expression in the AKCMS11 (sterile) buds. CONCLUSION: The comparative transcriptome findings suggest the potential role of these DEGs in pollen development or abortion, pointing towards their involvement in cytoplasmic male-sterility in pigeon pea. The candidate DEGs identified in this investigation will be highly significant for further research, as they could lend a comprehensive basis in unravelling the molecular mechanism governing CMS in pigeon pea.

Non-coding RNAs having strong positive interaction with mRNAs reveal their regulatory nature during flowering in a wild relative of pigeonpea (Cajanus scarabaeoides).

In higher plants, flower development is a result of crosstalk between many factors like photoperiod, vernalization, hormone concentration, epigenetic modification etc. and is also regulated by non-coding RNAs (ncRNAs). In the present study, we are reporting the involvement of long non-coding RNAs (lncRNAs) and miRNAs during the process of flower development in Cajanus scarabaeoides, an important wild relative of pigeonpea. The transcriptome of floral and leaf tissues revealed a total of 1672 lncRNAs and 57 miRNAs being expressed during flower development. Prediction analysis of identified lncRNAs showed that 1593 lncRNAs were targeting 3420 mRNAs and among these, 98 were transcription factors (TFs) belonging to 48 groups. All the identified 57 miRNAs were novel, suggesting their genera specificity. Prediction of the secondary structure of lncRNAs and miRNAs followed by interaction analysis revealed that 199 lncRNAs could interact with 47 miRNAs where miRNAs were acting in the root of interaction. Gene Ontology of the ncRNAs and their targets showed the potential role of lncRNAs and miRNAs in the flower development of C. scarabaeoides. Among the identified interactions, 17 lncRNAs were endogenous target mimics (eTMs) for miRNAs that target flowering-related transcription factors. Expression analysis of identified transcripts revealed that higher expression of Csa-lncRNA_1231 in the bud sequesters Csa-miRNA-156b by indirectly mimicking the miRNA and leading to increased expression of flower-specific SQUAMOSA promoter-binding protein-like (SPL-12) TF indicating their potential role in flower development. The present study will help in understanding the molecular regulatory mechanism governing the induction of flowering in C. scarabaeoides.

Comparative analysis of chromosome 2A molecular organization in diploid and hexaploid wheat.

Diploid A genome wheat species harbor immense genetic variability which has been targeted and proven useful in wheat improvement. Development and deployment of sequence-based markers has opened avenues for comparative analysis, gene transfer and marker assisted selection (MAS) using high throughput cost effective genotyping techniques. Chromosome 2A of wheat is known to harbor several economically important genes. The present study aimed at identification of genic sequences corresponding to full length cDNAs and mining of SSRs and ISBPs from 2A draft sequence assembly of hexaploid wheat cv. Chinese Spring for marker development. In total, 1029 primer pairs including 478 gene derived, 501 SSRs and 50 ISBPs were amplified in diploid A genome species Triticum monococcum and T. boeoticum identifying 221 polymorphic loci. Out of these, 119 markers were mapped onto a pre-existing chromosome 2A genetic map consisting of 42 mapped markers. The enriched genetic map constituted 161 mapped markers with final map length of 549.6 cM. Further, 2A genetic map of T. monococcum was anchored to the physical map of 2A of cv. Chinese Spring which revealed several rearrangements between the two species. The present study generated a highly saturated genetic map of 2A and physical anchoring of genetically mapped markers revealed a complex genetic architecture of chromosome 2A that needs to be investigated further.

Copro-prevalence and Risk Factor Assessment of Gastrointestinal Parasitism in Indian Domestic Pigs.

The aim of the present study was to determine copro-prevalence of gastrointestinal parasites and their associated potential risk factors in pigs of Punjab (India). A total of 839 faecal samples were collected from pigs of all age group and sex from different agro-climatic zones of Punjab covering all seasons and subjected to qualitative and quantitative examination. Among the samples examined, 28.4 % were positive for gastrointestinal parasites and their respective prevalences were Ascaris suum (11.1 %), coccidia (9.41 %), Trichuris suis (6.43 %), Balantidium coli (4.5 %), amphistome (3.33 %), strongyle (2.14 %) and Ascarops strongylina (1.78 %). Upon sporulation of coccidian positive samples, 8 species of Eimeria were recorded (Eimeria polita, E. spinosa, E. scabra, E. perminuta, E. suis, E. debliecki, E. neodebliecki and E. porci). Among the various risk factors analysed, season, agro-climatic zones and managemental practices had a signifi cant (p<0.05) effect on gastrointestinal parasitism of pigs. Quantification of the infection levels in various seasons and age groups revealed the highest mean egg per gram in rainy season (1966. 6± 1146.5) and grower pigs (1457.1 ± 500.4). Coproculture analysis revealed the presence of larvae of Hyostrongylus rubidus and Oesophagostomum species. The results of the current study would be of immense help in formulation and implementation of control strategies for effective control of gastrointestinal parasitism in pigs.

Changes in middle ear transmission characteristics secondary to altered bone remodelling.

Alteration in the process of bone remodelling results in conditions like osteopenia and osteoporosis in which the bones become susceptible to fracture. The functioning of middle ear bones in such individuals were assessed in this study and it was found that the middle ear bones are equally susceptible to micro-fractures and can cause reduction in the transmission of sound energy. INTRODUCTION: Alteration in the process of bone remodelling or increase in the number of osteoclasts cells as it occurs in osteoporosis and osteopenia are likely to affect the middle ear bones in the same way it affects the skeletal bones. Whether these micro-structural changes occurring at the level of the middle ear secondary to altered bone remodelling cause any significant impairment in its functioning is not explored. Thus, the present study aimed at assessing the different aspects of middle ear functioning in individuals with reduced BMD. METHODS: The study included 25 normal, 39 osteopenic and 40 osteoporotic participants. The participants underwent pure-tone audiometry, otoscopic examination, conventional immittance evaluation using a 226 Hz probe tone, multi-component and multi-frequency tympanometry and acoustic reflex threshold testing. None of the participants had any current or previous history of middle ear effusion. RESULTS: A significantly higher proportion of participants in the clinical group had hearing loss compared to the normal group. The clinical group participants also had reduced middle ear resonance frequency, elevated static compliance values and elevated or absent acoustic reflexes compared to the normal participants. There was no difference among the three groups for the proportion of participants having conductive hearing loss. CONCLUSIONS: There is a detrimental impact of reduction in bone mineral density on middle ear transmission characteristics which may go unnoticed initially. Treatment of osteoporosis may potentially mitigate hearing loss from middle ear fractures due to reduced bone mineral density. Absence of significant air-bone gap with the presence of reduced middle ear resonance frequency may be early signs of reduced BMD.

Synthetic pyrethroid resistance in Rhipicephalus (Boophilus) microplus ticks from north-western Himalayas, India.

In the present study, adult immersion test (AIT) was used for evaluation of resistance against synthetic pyrethroids (deltamethrin and cypermethrin) in Rhipicephalus (Boophilus) microplus ticks collected from nine districts of three agro-climatic zones of north-western Himalayan region of India. Resistance factors (RFs) were calculated between 0.94 to 50.71 for deltamethrin and 0.32 to 13.18 for cypermethrin. Resistance to deltamethrin was detected at level I in two, level II in four, level III and level IV in one isolate each while one isolate was susceptible. Against cypermethrin, resistance at levels I and II was detected in three isolates each while three isolates were found susceptible. The low altitude sub-tropical zone revealed higher density of resistant ticks where intensive animal husbandry practices were followed and the synthetic pyrethroid usage was common. Data generated on pyrethroid resistance status of ticks in north-western Himalayan region will provide new insights in acaricidal resistance particularly from remote areas of this region and will help in formulating suitable control measures.

Molecular analysis of anthocyanin biosynthesis pathway genes and their differential expression in mango peel.

Mango fruit is cherished by masses for its taste and nutrition, contributed by color, flavor, and aroma. Among these, peel color is an important trait contributing to fruit quality and market value. We attempted to elucidate the role of key genes of the anthocyanin biosynthesis pathway related to fruit peel color from the leaf transcriptome of mango cultivar Amrapali. A total of 108 mined transcript sequences were assigned to the phenylpropanoid-flavonoid pathway from which 15 contigs representing anthocyanin biosynthesis genes were annotated. Alternate splice variants were identified by mapping against genes of Citrus clementina and Vitis vinifera (closest relatives) and protein subcellular localization was determined. Phylogenetic analysis of these pathway genes clustered them into distinct groups aligning with homologous genes of Magnifera indica, C. clementina, and V. vinifera. Expression profiling revealed higher relative fold expressions in mature fruit peel of red-colored varieties (Arunika, Ambika, and Tommy Atkins) in comparison with the green-peeled Amrapali. MiCHS, MiCHI, and MiF3H alternate splice variants revealed differential gene expression. Functionally divergent variants indicate availability of an allelic pool programmed to play critical roles in peel color. This study provides insight into the molecular genetic basis of peel color and offers scope for development of biomarkers in varietal improvement programs.

Differential characterization of myogenic satellite cells with linolenic and retinoic acid in the presence of thiazolidinediones from prepubertal Korean black goats.

OBJECTIVE: Myogenic satellite cells were isolated from semitendinosus muscle of prepubertal Korean black goat to observe the differential effect of linolenic and retinoic acid in thepresence of thiazolidinediones (TZD) and also to observe the production insulin sensitive preadipocyte. METHODS: Cells were characterized for their stemness with cluster of differentiation 34 (CD34), CD13, CD106, CD44, Vimentin surface markers using flow cytometry. Cells characterized themselves as possessing significant (p<0.05) levels of CD13, CD34, CD106, Vimentin revealing their stemness potential. Goat myogenic satellite cells also exhibited CD44, indicating that they possessed a % of stemness factors of adipose lineage apart from their inherent stemness of paxillin factors 3/7. RESULTS: Cells during proliferation stayed absolutely and firmly within the myogenic fate without any external cues and continued to show a significant (p<0.05) fusion index % to express myogenic differentiation, myosin heavy chain, and smooth muscle actin in 2% horse serum. However, confluent myogenic satellite cells were the ones easily turning into adipogenic lineage. Intriguingly, upregulation in adipose specific genetic markers such as peroxisome proliferation-activated receptor γ, adiponectin, lipoprotein lipase, and CCAAT/enhancer binding protein α were observed and confirmed in all given treatments. However, the amount of adipogenesis was found to be statistically significant (p<0.01) with linolenic acid as compared to retinoic acid in combination with TZD's. CONCLUSION: Retinoic acid was found to produce smaller preadipocytes which have been assumed to have insulin sensitization and hence retinoic acid could be used as a potential agent to sensitize tissues to insulin in combination with TZD's to treat diabetic conditions in humans and animals in future.

Exploring diverse wheat germplasm for novel alleles in HMW-GS for bread quality improvement.

Wheat is one of the most important cereals used worldwide in the form of a range of products. Crop landraces have been an immense source of diversity for the breeders. In the present study, 517 Indian wheat landraces have been observed for the difference in bread making quality by assessing allelic behaviour of high molecular weight-glutenin subunits (HMW-GS). A total of 33 Glu-1 alleles (3 at Glu-A1, 15 at Glu-B1 and 15 at Glu-D1) were detected in wheat landraces. Allelic frequency of HMW-GS allelic band pattern null, 17 + 18, 2 + 12 (24.75%) was found to be the highest. Allelic frequency of HMW-GS allele null (68.27%) at Glu-A1, 17 + 18 (49.14%) at Glu-B1, and 2 + 12 (72.81%) at Glu-D1 was found to be the highest Five Novel alleles were identified at Glu-D1 locus, 12*, 12.1, 12.1*, 12.2 and 12.3. As Glu-D1 has highest quality contribution as compared to Glu-A1 and Glu-B1, reporting novel alleles at Glu-D1 represents that genetic variability available for selection is increased and it will provide tools for breeders to further improve dough properties and bread making quality.

Detection of amitraz and malathion resistance in field populations of Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) in Jammu region of India.

Detection of resistance levels against amitraz and malathion in Rhipicephalus (Boophilus) microplus collected from four districts of Jammu region (India) was carried out using the adult immersion test. The regression graphs of probit mortality of ticks plotted against log values of concentration of drugs were utilised for the determination of slope of mortality, lethal concentration for 50% (LC50), 95% (LC95) and resistance factor (RF). On the basis of the data generated on variables (mortality, egg mass weight, reproductive index and percentage inhibition of oviposition) the resistance level was categorised as I, II, III and IV. Out of these four districts, resistance to amitraz was detected at level I in Udhampur (RF = 2.81), Jammu (RF = 2.53) and Samba isolates (RF = 2.24) whereas Rajouri isolate was found susceptible (RF = 1.0). Resistance to malathion was detected at level I in Udhampur (RF = 4.01) and Jammu isolates (RF = 1.76) whereas Rajouri (RF = 0.472) and Samba (RF = 0.199) isolates were found susceptible. The data generated on amitraz and malathion resistance status will help in formulating a tick control strategy in the region.

A Young Boy with L-asparaginase-Induced Seizure.

L-Asparaginase is a critical component in the treatment of acute lymphoblastic leukemia in children. It is known to cause coagulation abnormalities, thrombosis and hemorrhage in the central nervous system in addition to vasculitis and hypersensitivity reactions. This syndrome generally occurs after a few weeks of therapy and may occur after L-asparaginase therapy is completed. Seizures are uncommon symptoms. We report a case of seizure associated with L-asparaginase therapy but no evidence of hemorrhagic or thrombotic cerebrovascular events, completed in the department of Hematology of Bangabandhu Sheikh Mujib Medical University during March & April 2016.

Unraveling the molecular basis of oxidative stress management in a drought tolerant rice genotype Nagina 22.

BACKGROUND: Drought stress tolerance for crop improvement is an important goal worldwide. Drought is a complex trait, and it is vital to understand the complex physiological, biochemical, and molecular mechanisms of drought tolerance to tackle it effectively. Osmotic adjustment, oxidative stress management (OSM), and cell membrane stability (CMS) are major components of cellular tolerance under drought stress. In the current study, we explored the molecular basis of OSM in the drought tolerant rice variety, Nagina 22 and compared it with the popular drought sensitive rice variety, IR 64, under drought imposed at the reproductive stage, to understand how the parental polymorphisms correlate with the superiority of Nagina 22 and tolerant bulk populations under drought. RESULTS: We generated recombinant inbred lines (RIL) from contrasting parents Nagina 22 and IR 64 and focussed on spikelet fertility (SF), in terms of its correlation with OSM, which is an important component of drought tolerance in Nagina 22. Based on SF under drought stress and its correlations with other yield related traits, we used superoxide dismutase (SOD), glutathione reductase (GR), and ascorbate peroxidase (APX) activity assays to establish the relationship between SF and OSM genes in the tolerant and sensitive lines. Among the OSM enzymes studied, GR had a significant and positive correlation with single plant yield (SPY) under drought stress. GR was also positively correlated with APX but negatively so with SOD. Interestingly, none of the enzyme-morphology correlations were significant under irrigated control (IC). Through genome-wide SNP analysis of the 21 genes encoding for OSM enzymes, we identified the functional polymorphisms between the parents and identified superior alleles. By using network analysis of OSM genes in rice, we identified the genes that are central to the OSM network. CONCLUSIONS: From the biochemical and morphological data and the SNP analysis, the superiority of Nagina 22 in spikelet fertility under drought stress is because of its superior alleles for SOD (SOD2, SODCC1, SODA) and GR (GRCP2) rather than for APX, for which IR 64 had the superior allele (APX8). Nagina 22 can bypass APX8 by directly interacting with SODA. For nine of the 11 genes present in the central network, Nagina 22 had the superior alleles. We propose that Nagina 22 tolerance could mainly be because of SODA which is a reactive oxygen scavenger in mitochondria which is directly associated with spikelet fertility.

Identification and gene-silencing of a putative odorant receptor transcription factor in Varroa destructor: possible role in olfaction.

The ectoparasitic mite Varroa destructor is one of the major threats to apiculture. Using a behavioural choice bioassay, we determined that phoretic mites were more successful in reaching a bee than reproductive mites, suggesting an energy trade-off between reproduction and host selection. We used both chemo-ecological and molecular strategies to identify the regulation of the olfactory machinery of Varroa and its association with reproduction. We focused on transcription regulation. Using primers designed to the conserved DNA binding region of transcription factors, we identified a gene transcript in V. destructor homologous to the pheromone receptor transcription factor (PRTF) gene of Pediculus humanus corporis. Quantitative PCR (qPCR) revealed that this PRTF-like gene transcript is expressed in the forelegs at higher levels than in the body devoid of forelegs. Subsequent comparative qPCR analysis showed that transcript expression was significantly higher in the phoretic as compared to the reproductive stage. Electrophysiological and behavioural studies revealed a reduction in the sensitivity of PRTF RNA interference-silenced mites to bee headspace, consistent with a reduction in the mites' ability to reach a host. In addition, vitellogenin expression was stimulated in PRTF-silenced mites to similar levels as found in reproductive mites. These data shed light upon the regulatory mechanism of host chemosensing in V. destructor.

Genetic diversity trend in Indian rice varieties: an analysis using SSR markers.

BACKGROUND: The knowledge of the extent and pattern of diversity in the crop species is a prerequisite for any crop improvement as it helps breeders in deciding suitable breeding strategies for their future improvement. Rice is the main staple crop in India with the large number of varieties released every year. Studies based on the small set of rice genotypes have reported a loss in genetic diversity especially after green revolution. However, a detailed study of the trend of diversity in Indian rice varieties is lacking. SSR markers have proven to be a marker of choice for studying the genetic diversity. Therefore, the present study was undertaken with the aim to characterize and assess trends of genetic diversity in a large set of Indian rice varieties (released between 1940-2013), conserved in the National Gene Bank of India using SSR markers. RESULT: A set of 729 Indian rice varieties were genotyped using 36 HvSSR markers to assess the genetic diversity and genetic relationship. A total of 112 alleles was amplified with an average of 3.11 alleles per locus with mean Polymorphic Information Content (PIC) value of 0.29. Cluster analysis grouped these varieties into two clusters whereas the model based population structure divided them into three populations. AMOVA study based on hierarchical cluster and model based approach showed 3 % and 11 % variation between the populations, respectively. Decadal analysis for gene diversity and PIC showed increasing trend from 1940 to 2005, thereafter values for both the parameters showed decreasing trend between years 2006-2013. In contrast to this, allele number demonstrated increasing trend in these varieties released and notified between1940 to 1985, it remained nearly constant during 1986 to 2005 and again showed an increasing trend. CONCLUSION: Our results demonstrated that the Indian rice varieties harbors huge amount of genetic diversity. However, the trait based improvement program in the last decades forced breeders to rely on few parents, which resulted in loss of gene diversity during 2006 to 2013. The present study indicates the need for broadening the genetic base of Indian rice varieties through the use of diverse parents in the current breeding program.

Amelioration of arsenic toxicity in rice: Comparative effect of inoculation of Chlorella vulgaris and Nannochloropsis sp. on growth, biochemical changes and arsenic uptake.

The present study was conducted to assess the responses of rice (Oryza sativa L. var. Triguna) by inoculating alga; Chlorella vulgaris and Nannochlropsis sp. supplemented with As(III) (50µM) under hydroponics condition. Results showed that reduced growth variables and protein content in rice plant caused by As toxicity were restored in the algae inoculated plants after 7d of treatment. The rice plant inoculated with Nannochloropsis sp. exhibited a better response in terms of increased root, shoot length and biomass than C. vulgaris under As(III) treatment. A significant reduction in cellular toxicity (thiobarbituric acid reactive substances) and antioxidant enzyme (SOD, APX and GR) activities were observed in algae inoculated rice plant under As(III) treatment in comparison to uninoculated rice. In addition, rice treated with As(III), accumulated 35.05mgkg(-1)dw arsenic in the root and 29.96mgkg(-1)dw in the shoot. However, lower accumulation was observed in As(III) treated rice inoculated with C. vulgaris (24.09mg kg(-1)dw) and Nannochloropsis sp. (20.66mgkg(-1)dw) in the roots, while in shoot, it was 20.10mgkg(-1)dw and 11.67mgkg(-1)dw, respectively. Results demonstrated that application of these algal inoculum ameliorates toxicity and improved tolerance in rice through reduced As uptake and modulating antioxidant enzymes. Thus, application of algae could provide a low-cost and eco-friendly mitigation approach to reduce accumulation of arsenic in edible part of rice as well as higher yield in the As contaminated agricultural field.

Arsenic and other heavy metal accumulation in plants and algae growing naturally in contaminated area of West Bengal, India.

The present study was conducted to quantify the arsenic (As) and other heavy metal concentrations in the plants and algae growing naturally in As contaminated blocks of North-24-Pargana and Nandia district, West Bengal, India to assess their bioaccumulation potential. The plant species included five macrophytes and five algae were collected from the nine selected sites for estimation of As and other heavy metals accumulated therein by using Inductively Coupled Plasma Mass Spectrophotometer (ICP-MS). Results revealed that maximum As concentration (117mgkg(-1)) was recorded in the agricultural soil at the Barasat followed by Beliaghat (111mgkg(-1)) sites of North-24-Pargana. Similarly, concentration of selenium (Si, 249mgkg(-1)), lead (Pb, 79.4mgkg(-1)), chromium (Cr, 138mgkg(-1)) was also found maximum in the soil at Barasat and cadmium (Cd, 163mgkg(-1)) nickel (Ni, 36.5mgkg(-1)) at Vijaynagar site. Among the macrophytes, Eichhornia crassipes found more dominating species in As contaminated area and accumulate As (597mgkg(-1)) in the shoot at kanchrapara site. The Lemna minor found to accumulate maximum As (735mgkg(-1)) in the leaves at Sonadanga and Pistia stratiotes accumulated minimum As (24.5mgkg(-1)) in the fronds from Ranaghat site. In case of diatoms, maximum As (760mgkg(-1)) was accumulated at Kanchrapara site followed by Hydrodictiyon reticulatum (403mgkg(-1)) at the Ranaghat site. High concentration of As and other heavy metal in soil indicates long term effects of irrigation with contaminated ground water, however, high concentration of heavy metals in naturally growing plants and algae revealed their mobilization through leaching and possible food chain contamination. Therefore, efficient heavy metal accumulator macrophytes Eichhornia crassipes, Lemna minor, Spirodela polyrhiza may be exploited in removing metals from contaminated water by developing a plant based treatment system. However, As accumulator algal species may be used as a bioresource for understanding algae mediated As detoxification and bioindication studies.

Performance of fenugreek bioinoculated with Rhizobium meliloti strains under semi-arid condition.

Rhizobium meliloti strains were isolated from the fields of S.D. Agricultural University (Gujarat, India) and were maintained in the Congo Red Yeast Extract Mannitol Agar medium. These strains were tested for their effectiveness for fenugreek crop grown under semi-arid condition. Among the six Rhizobium strains, FRS-7 strain showed best plant growth parameters like shoot length, shoot dry weight, shoot total nitrogen, root length, root dry weight, root total nitrogen, seed yield, 1000 grain weight, number of root nodules, and nodules fresh and dry weight. The performance of this strain was better as compared to 20 kgN ha(-1) treatment through urea and was even far better over control plot. Seed yields obtained with FRS-7 during two years were 10.14 and 9.66 q ha(-1); which was about 36.8% and 45.9% high over control. This strain resulted in saving of about 20 kgN ha(-1) accompanied with better crop yield and soil health. Results of the present experiments can be utilized in integrated nutrient management for cultivation of fenugreek in semi-arid areas to provide sustainability to agricultural productivity in such regions.