Identification of quantitative trait loci associated with iron deficiency chlorosis resistance in groundnut (Arachis hypogaea)

Iron deficiency chlorosis is an important abiotic stress affecting groundnut production worldwide in calcareous and alkaline soils with a pH of 7.5–8.5. To identify genomic regions controlling iron deficiency chlorosis resistance in groundnut, the recombinant inbred line population from the cross TAG 24 × ICGV 86031 was evaluated for associated traits like visual chlorosis rating and SPAD chlorophyll meter reading across three crop growth stages for two consecutive years. Thirty-two QTLs were identified for visual chlorosis rating (3.9%–31.8% phenotypic variance explained [PVE]) and SPAD chlorophyll meter reading [3.8%–11% PVE] across three stages over 2 years. This is the first report of identification of QTLs for iron deficiency chlorosis resistance-associated traits in groundnut. Three major QTLs (>10% PVE) were identified at severe stage, while majority of other QTLs were having small effects. Interestingly, two major QTLs for visual chlorosis rating at 60 days (2013) and 90 days (2014) were located at same position on LG AhXIII. The identified QTLs/markers after validation across diverse genetic material could be used in genomics-assisted breeding.     

A transient radio jet in an erupting dwarf nova

Astrophysical jets seem to occur in nearly all types of accreting objects, from supermassive black holes to young stellar objects. On the basis of x-ray binaries, a unified scenario describing the disc/jet coupling has evolved and been extended to many accreting objects. The only major exceptions are thought to be cataclysmic variables: Dwarf novae, weakly accreting white dwarfs, show similar outburst behavior to x-ray binaries, but no jet has yet been detected. Here we present radio observations of a dwarf nova in outburst showing variable flat-spectrum radio emission that is best explained as synchrotron emission originating in a transient jet. Both the inferred jet power and the relation to the outburst cycle are analogous to those seen in x-ray binaries, suggesting that the disc/jet coupling mechanism is ubiquitous.     

Biodegradation of hexachlorocyclohexane-isomers in contaminated soils

Several sites that are contaminated with isomers of the chlorinated insecticide hexachlorocyclohexane (HCH) are present across the globe and cause toxicity. For their bioremediation, we studied the degradation of HCH-isomers in contaminated soils by an isolate Pseudomonas aeruginosa ITRC-5. The degradation is optimal at 2 mg technical-HCH (t-HCH)/g soil, 15% water content, pH 8.0, temperature 28 °C and inoculum density 10⁶ colony forming unit/g soil. Under these conditions, from 5 kg soil, >98% α- and γ-HCH, 17% β-HCH and 76% δ-HCH are degraded after 15 days of incubation, which is accompanied with the release of 600 μg chloride/mg t-HCH. Concomitant to the degradation, a four-fold reduction in the toxicity of HCH-isomers to earthworm, Eisenia foetida, is also observed. Addition of ITRC-5 enhanced the degradation of soil-applied HCH-isomers in ‘open field’ conditions as well, and 97%, 43%, 94% and 77% of α-, β-, γ- and δ-HCH, respectively, are degraded after 12 weeks of incubation. Thus, the bacterium causes microbial degradation and detoxification of HCH-isomers, and can be used for the bioremediation of contaminated soils.     

Anti-viral activity of methyl 1-chloro-7-methyl-2-propyl-1h-benzo[d] imidazole-5-carboxylate against white spot syndrome virus in freshwater crab (Paratelphusa hydrodromous)

Shrimp farming industries are subjected to severe economic loss due to a disease called white spot syndrome, a viral disease caused by white spot syndrome virus (WSSV) in penaeid shrimp. Numerous active compounds in the market possess anti-viral activity against the white spot syndrome virus, yet the issue remains unsolved. The present study was carried out to determine the anti-viral activity of methyl 1-chloro-7-methyl-2-propyl-1h-benzo[d] imidazole-5-carboxylate (C₁₃H₁₅N₂O₂Cl) against WSSV. The anti-viral activity of the synthetic compound was determined in freshwater crabs. Crabs were divided into three different experimental groups: healthy control groups (N.C.) received NTE buffer, positive control group (P.C.) crabs received WSSV, and treatment group crabs received WSSV along with synthetic weight compound. Experimental groups were observed for 30 days post-infection. Three different organs (gills, muscles, and head soft tissue (HST)) were dissected from all three groups and analyzed using molecular-based techniques, including polymerase chain reaction (PCR), Western blot, and histopathology. Clinical signs of WSSV were observed in the positive and N.C. groups; however, the treatment group showed a 100% survival rate. Confirmation was done using PCR, Western blot, and histopathology. These results demonstrated that the given synthetic compound has significant anti-viral activity against WSSV.

     

HPTLC analysis of guggulsterone isomers in Commiphora wightii (Arn.) Bhandari: an endangered oleo-gum resin species heading towards extinction

The oleo-gum resin of Commiphora wightii (Arn.) Bhandari, a pharmacologically important balsamiferous woody shrub, has been used in treating various ailments and disorders since ancient times (2000 B.C.) due to the presence of steroidal compound guggulsterone. Two bioactive isomers of guggulsterone, E and Z, are responsible for lipid- and cholesterol-lowering and anti-cancerous activities. Further, guggul has been approved as food supplement by US-FDA as well as Council of Europe. Indiscriminate harvest of C. wightii from wild with negligible conservation efforts has lead to its inclusion in IUCN assemblage of endangered plant species. For identification of high guggulsterone yielding ecotypes of C. wightii, using high-performance thin-layer chromatographic (HPTLC) analysis, stem samples were collected from 50 plants from eleven locations in arid tracts of Haryana, Gujarat and Rajasthan. Dried, powdered material was subjected to extraction with petroleum ether using soxhlet apparatus. Samples were spotted on precoated activated silica plates (60F-254) and were developed using toluene–acetone (9:1 v/v) as mobile phase. The analysis was carried out in the absorbance mode at 250 nm using HPTLC scanner. The regression analysis data for the calibration plots for E and Z guggulsterone showed good linear relationship with R² = 1 and 0.9897, respectively. Highest concentration of guggulsterone E (284 μg/g dry wt) was found in the accession collected from Palana, Bikaner whereas highest guggulsterone Z concentration (89.5 μg/g dry wt) was found in the accession collected from CAZRI, Jodhpur.     

Whitebacked planthopper Sogatella furcifera (Horváth) (Homoptera: Delphacidae) resistance in rice variety Sinna Sivappu

Whitebacked planthopper (WBPH) along with brown planthopper (BPH) has emerged as a major pest of rice in several Asian countries. Development and cultivation of varieties resistant to both planthoppers is an ecologically acceptable strategy to manage these pests. Sinna Sivappu, a Sri Lankan landrace, was reported to be resistant to both planthoppers. While inheritance of BPH resistance has been reported, the genetics of WBPH resistance in this variety is not known. Using a mapping population of 255 F_2:3 families from Taichung Native (TN)1/Sinna Sivappu cross and 128 polymorphic simple sequence repeat (SSR) markers, genes or quantitative trait loci (QTLs) for WBPH resistance quantified in ten phenotypic tests were identified, adopting classical Mendelian segregation, correlation and QTL analyses. The inheritance pattern suggested that a single recessive gene controlled regulation of seedling damage score. Antixenosis or nymphal preference was influenced by two complementary recessive genes, whereas tolerance in terms of days to wilt was under the influence of a single dominant gene. Several of these phenotypic tests recorded high degree of positive or negative correlation between them, suggesting dependence or redundancy of the tests. QTL analysis revealed 13 loci associated with nine traits. Five major-effect QTLs were detected for damage score (chromosome 6), nymphal survival (chromosome 12), and days to wilt (three QTLs on chromosome 4). We suggest involvement of four WBPH resistance genes in Sinna Sivappu, designated as wbph9(t), wbph10(t), wbph11(t), and Wbph12(t). One of the recessive genes could be allelic to any of the recessive genes reported in cluster C on chromosome 6 which might confer resistance to both BPH and WBPH.     

Efficacy of vaccination with La Sota strain vaccine to control Newcastle disease in village chickens in Nepal

The efficacy of vaccination with Newcastle disease (ND) La Sota and R₂B (Mukteswar) modified live strain vaccines was determined by experimental challenge and with ND La Sota vaccine under field conditions in Nepal. Booster vaccination with ND La Sota vaccine after a primary vaccination with ND La Sota vaccine, induced a geometric mean titre (GMT) of 5.0 log₂ haemagglutination inhibition (HI) units, compared to a GMT of 6.0 log₂ HI units following booster vaccination with R₂B vaccine 1 month after primary vaccination with ND La Sota vaccine. Both vaccines provided 100% protection against challenge with a local field ND strain. Furthermore, booster vaccination with ND La Sota vaccine induced protective levels of antibody after field use in villages in Jhapa, and no outbreaks of ND occurred during the study period. The ND La Sota modified live vaccine is immunogenic and efficacious and is a suitable vaccine for use in vaccination programmes in village chickens in the rural areas of Nepal.

     

Evaluation of a Suitable Extractant and Determination of Critical Limit of Boron in Soil and Mustard (Brassica Juncea L.) Plant by Various Extractants in Inceptisols of Varanasi

Pot culture experiment was conducted to evaluate the suitability of extractants and to determine the critical limit of boron (B) in soil and mustard plant in Inceptisols of Varanasi. Twenty-one bulk soil collected from different locations were used for growing mustard. Five extractants, namely hot water, hot 0.01molar (M) calcium chloride (CaCl₂), 0.01M CaCl₂ + 0.05 M mannitol, 1.0 M ammonium acetate (NH₄OAC) and 0.05 M hydrochloric acid (HCl), were assessed by correlating the amount of extractable B in untreated and B fertilizer-treated soil with Bray’s per cent yield, plant tissue B concentration and B uptake by mustard. Similarly, correlation coefficients of the B extracted by different extractants and soil properties were calculated. The suitability of B extracted by different extractants was in the order of hot 0.01M CaCl₂ (HCC-B) > hot water (HW-B) > 1.0 M NH₄OAC (AA-B) > 0.05M HCl (HA-B) > 0.01M CaCl₂ + 0.05M mannitol (CCM-B). The critical limits of extractable B in soil as determined by the graphical procedure were 0.54, 0.60, 0.36, 0.45 and 0.45 mg kg^?1 and the statistical procedures were 0.54, 0.60, 0.38, 0.46 and 0.48 mg kg^?1 with HW-B, HCC-B, CCM-B, AA-B and HA-B, respectively. Soil containing available B below the critical limit responded to B fertilization.     

Effect of paclobutrazol and salinity on ion leakage,proline content and activities of antioxidant enzymes in mango (Mangifera indica L.)

A study was conducted to investigate the effects of paclobutrazol (PBZ) on ion leakage (IL), proline content and activities of antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) of 1-year-old ‘Olour’ mango plants subjected to NaCl stress. Plants were treated with two levels of salt, i.e., 0.0 g NaCl (control) and 25 g NaCl/25 kg soil and three levels of paclobutrazol (PBZ) solution (0.0 (control), 750 and 1500 mg/l). Ion leakage, proline content and activities of antioxidant enzymes were significantly altered by both salinity and PBZ treatments. Results indicated that PBZ (1500 mg/l) mitigated the salinity stress and reduced ion leakage of mango seedlings by 64% over non-PBZ-treated salinised plants. PBZ upregulated the endogenous proline content and salinised plants treated with PBZ (1500 mg/l) had 17% higher proline content than salinised plants without PBZ treatment. Higher antioxidant enzyme activity was also observed in salinised plants treated by PBZ than salinised plants without PBZ treatments. Moreover, higher dose of PBZ (1500 mg/l) resulted in higher activity of these enzymes in mango leaves. In comparison to salinised plants without PBZ treatment, salinised plants treated with PBZ (1500 mg/l) had higher SOD (24%), CAT (46%) and POD (163%) activities. Our results suggest that PBZ application under salt stress conditions alters the equilibrium between free radical production and enzymatic defense reactions in mango by enhancing the proline content and free radical scavenging capacity.     

First report of 16Sr II‐C subgroup phytoplasma association with Acacia mangium in Tripura,India

Leaf yellowing symptoms were observed on Acacia mangium in the Sipahijala district of Tripura, India, during June 2017. Symptomatic and asymptomatic leaf samples (three of each) were collected from roadside trees of A. mangium for DNA extraction using the CTAB method. Amplicons of ~1.25 kb and ~480 bp were detected in all the symptomatic samples using the phytoplasma‐specific universal 16S rRNA and secA gene primers. Pair wise sequence analysis of 16S rRNA gene sequences, virtual RFLP and phylogenetic analysis revealed that the phytoplasma strain associated with A. mangium belonged to phytoplasma subgroup 16SrII‐C. This is the first report of an association between the 16SrII‐C subgroup and A. mangium leaf yellowing.