Agrobacterium-mediated Cry1A(b) gene transfer in Punica granatum L. cv. Kandhari Kabuli using different In Vitro regeneration pathways

Three different regeneration systems, viz. regeneration through callus cultures using embryonic explant, direct regeneration using shoot bud/nodal segments as explant and regeneration through cell suspension culture using cotyledonary explant (for the induction of transgenic callus for suspension culture) were evaluated to see their effect on transfer of Cry1A(b) gene to Punica granatum L. cv. Kandhari Kabuli through Agrobacterium mediated transformation. Pre-conditioning and co-cultivation durations had a marked effect on transformation frequency of different explants. Out of different explants used (embryo, shoot bud, and cotyledon) for different regeneration systems cotyledonary explant showed highest putative transformation frequency (13.54%) inducing callus on selective medium for carrying out cell suspension culture to regenerate transgenic shoots. Despite of the highest transformation frequency obtained from the cotyledon explant, the plating efficiency of the transgenic cells generated through the transgenic callus (callus formed from the cotyledonary explant) during cell suspension culture was found to be very low (0.7%). Thus the plating efficiency has also played worth mentioning role in the regeneration of transformants following cell suspension culture. Among the three regeneration systems, regeneration through callus cultures using embryonic explant was found to be best for regeneration of transformants. The highest per cent regeneration of 23.33 was obtained from the putative transgenic embrogenic calli. Successful genetic transformation in the transformed plantlets was confirmed by PCR analysis. The transformation system thus developed is valuable and may be used to produce insect resistant trees.     

Classification of Dutch and German avian reoviruses by sequencing the sigma C protein

We have amplified, cloned and sequenced (part of) the open reading frame of the S1 segment encoding the sigma C protein of avian reoviruses isolated from chickens with different disease conditions in Germany and The Netherlands during 1980 up to 2000. These avian reoviruses were analysed phylogenetically and compared with sequences of avian reoviruses in the Genbank database. The avian reoviruses could be grouped in 5 different genotyping clusters and this classification was identical when the sequences were compared of the 5' end, the 3' end or the whole open reading frame of the sigma C protein. Therefore sequencing of either part of the gene encoding the sigma C protein seems to be reliable for classification. We were unable to identify a correlation between sigma C sequences of the avian reoviruses and the disease condition they were isolated from. The sequences found in The Netherlands and in Germany are, like those in Taiwan, more dispersed than the known avian reovirus sigma C sequences in the USA and Australia. We did not establish temporal or geographic differences in the avian reoviruses studied.     

Molecular breeding technologies and strategies for rust resistance in wheat (Triticum aestivum) for sustained food security

Wheat is an important cereal food crop providing key nutrients to humankind. Rusts are the most destructive pathogens of cereal crops, with the exception of rice, across the world and resistant cultivars have been widely employed to reduce the yield losses caused by them. The modern intensive monoculture of cultivars and changing climatic conditions has created congenial conditions for the emergence of new virulent races such as Ug99, which is a great concern for world food security. Conventional breeding efforts have not been effective in quickly developing new varieties with durable and broad‐spectrum resistance against the rapidly evolving rust pathogen races. However, in the last two decades, biotechnological methods such as marker‐assisted selection (MAS) and transgenic technology have provided novel strategies for enhancing resistance levels and durability in crop plants in a short span of time. Nevertheless, broad application of transgenics in agriculture is hindered by biosafety apprehensions. In recent years, improved versions of biotechnological breeding methods such as genomic selection, genome editing technologies, cisgenesis and intragenesis, RNA‐dependent DNA methylation (RdDM), agroinfiltration and reverse breeding are gaining popularity. These technologies provide a tremendous capability to manipulate crop plants more precisely than before and accelerate crop improvement efforts for sustained food production as well as overcoming safety concerns associated with food crops.     

A novel crop water analysis system: identification of water stress tolerant genotypes of canola (Brassica napus L.) using non‐invasive magnetic turgor pressure probes

Changing global climatic conditions and irrigation water shortages impose water stress conditions on crops. To develop genotypes tolerant to water stress necessitates reliable high‐throughput methods to study plant water status and water stress tolerance mechanisms. We report the use of a non‐destructive, automated, precise and rapid system for assessing real‐time water status in canola plants. Leaf patch clamp pressure probes were clamped on the leaves of four different genotypes of canola grown under field conditions. The data generated diurnal curves characterizing the pattern of turgor pressure maintenance within the leaves. A novel methodology termed ‘inverse hysteresis’ was developed to measure relative water stress levels in plants using the probe‐derived data. The inverse hysteresis data show that genotypes CT12 and CT15 had a higher ability to withstand water stress and were more tolerant to water stress than DS23 and DS35. The chlorophyll content and seed yield were also higher in CT12 and CT15. This novel analytical tool for monitoring water status in canola plants will be of great benefit in other crop species to efficiently screen genotypes for water stress tolerance.     

Cyanobacteria in alkaline soil and the effect of cyanobacteria inoculation with pyrite amendments on their reclamation

The succession of cyanobacteria was studied in a usar (alfisol, solonetz, alkaline) soil, located in a tropical region of upper Gangetic plain, following the first rainfall for a period of 10 months (i.e., July–April). A dozen cyanobacteria were identified to grow on the soil surface and their appearance was in the following order: Microcoleus sp., Calothrix brevissima, Scytonema sp., Cylindrosprmum licheniformae, Cylindrosprmum fertilissima, Nostoc calcicola, Nostoc punctiformae, Aphanothece parietina, Nostoc commune, Aulosira fertilissima, Phormidium sp., and Oscillatoria sp. Among these cyanobacteria, N. calcicola was the dominant species. N. calcicola was inoculated on the alkaline soil and incubated under ambient conditions in the light for 2 years in the laboratory. Changes in soil properties were more rapid after the incorporation of pyrite (FeS₂). Recovery was monitored by using a filamentous heterocystous cyanobacterium N. calcicola and its bicarbonate-resistant (HCO₃^–R) mutant. The mutant strain showed better response to modification of soil pH following growth in soil.     

Strategies for maximizing utilization of de-oiled rice bran (DORB) in the fish feed

De-oiled rice bran (DORB) is obtained after oil is removed from the rice bran. This is the commonly used ingredient in the feeding of Indian major carps due to its cheaper cost. DORB is used as a feed ingredient in cattle, poultry, and fish diet. Along with this, they are also used in making fiber-rich biscuits and extraction of an antioxidant compound like oryzanol and other industrial uses. Due to the increased competition, there will be a huge imbalance in the demand and supply for this ingredient in the years to come. DORB is associated with high fiber content, anti-nutrients, and non-starch polysaccharides which lead to its poor utilization resulting in a higher feed conversion ratio (FCR) in fish. Hence, the strategic utilization of this ingredient by solid-state fermentation, exogenous enzyme supplementation, and supplementing it with deficient nutrients like amino acids and fatty acids will help in improving the utilization of this ingredient.

     

Long-term effects of fertilization and manuring on productivity and soil biological properties under rice (Oryza sativa)–wheat (Triticum aestivum) sequence in Mollisols

Long-term effects of chemical fertilizers and farmyard manure (FYM) in rice (Oryza sativa)–wheat (Triticum aestivum) cropping system were monitored for two consecutive years after 38 and 39 years on productivity and soil biological properties of Mollisols. The study encompasses varying chemical fertilizer levels of optimum fertilizer rate (120, 26 and 37 kg ha^?1 N, P and K, respectively) for both the crops. The treatments were application of 50% NPK, 100% NPK, 150% NPK, 100% NPK + hand weeding (HW), 100% NPK + Zn, 100% NP, 100% N, 100% NPK + 15 t FYM ha^?1, 100% NPK(-S) and unfertilized control. The rice and wheat yields were highest with 100% NPK + 15 t FYM ha^?1. This treatment also gave maximum and significantly more counts of bacteria, fungi and actinomycetes in soil than all the other treatments after crop harvest. The soil microbial biomass C (410.0 and 407.5 µg g^?1) and N (44.53 and 48.30 µg g^?1) after rice and wheat, respectively, were highest with 100% NPK + 15 t FYM ha^?1, which were significantly higher over all the other treatments. The activities of soil enzymes like dehydrogenase, acid and alkaline phosphatase, arylsulphatase and urease and CO₂ evolution rate with 100% NPK + 15 t FYM ha^?1 were also found significantly higher over the other treatments. Fertilizer treatments with 100% NPK and 150% NPK were comparable and significantly better than application of 50% NPK, 100% N, 100% NP and 100% NPK(-S) in various studied soil biological properties. Integrated use of 100% NPK with FYM sustained the higher yields and soil biological properties under rice–wheat cropping system in Mollisols. Application of Zn and hand weeding with 100% NPK were found better over 100% NPK alone in rice and wheat productivity. Imbalanced use of chemical fertilizers had the harmful effect on soil biological health.     

Carbohydrate metabolism changes in fish fingerlings and yearlings exposed to linear alkyl benzene sulphonate

Exposure of fish fingerlings (Cirrhina mrigala) and yearlings (Puntius sophore) to a concentration of 0.005 mg L^?1 of linear alkyl benzene sulphonate for 24, 48, and 96 hr caused alterations in glycogen, lactic acid and sialic acid content in gill, liver, muscles and kidney. Significant decreases in the level of glycogen and elevation in the level of lactic acid demonstrated impairment of carbohydrate metabolism. Decrease in the sialic acid content suggested functional changes in membranes in toxicity.