Molecular identification of blast resistance genes in rice landraces from northeastern India

Rice blast disease caused by the fungus Magnaporthe oryzae is one of the most devastating diseases causing huge losses worldwide. In the present study, major blast resistance genes were investigated in landraces originating from northeastern India. Based on phenotypic evaluation, 288 landraces were classified into three distinct groups: resistant (75), moderately resistant (127) and susceptible (86). The genetic frequencies of the 18 major blast resistance genes were between 6.2% and 27.4%, with only two genotypes possessing a maximum of nine blast resistance genes. The cluster and population structure analysis grouped the landraces into two groups. Through principal coordinate analysis, the scatter plots partitioned the resistant and moderately resistant landraces into different groups. Analysis of molecular variance showed maximum (96%) diversity within populations and least (4%) diversity between populations. Association analysis identified six markers, CRG4_2, RM72, tk59-2, pi21_79-3, RM1233 and RM6648, that are significantly associated with blast disease and explained a phenotypic variance of 1.1–6.5%. The associated genes could be used in marker-assisted rice breeding programmes for gene pyramiding to develop rice varietal resistance against blast disease. The present study represents a valuable blast resistance genetic resource that could be used for identification of new R genes, donors for blast resistance, and genomic studies.     

Biodegradation of the gamma isomer of benzene hexachloride in submerged soils

Determination of the residual gamma isomer of benzene hexachloride (gamma-BHC) by gas chromatography showed that the insecticide persisted longer in sterilized flooded soils than in nonsterilized flooded soils. A second addition of gamma-BHC to one of the nonsterilized soils. (55 days after the first application) disappepsilonared more rapidly than the first addition. These results strongly indicate biodegradation of gamma-BHC in flooded soils.     

In vitro Development of Buffalo Oocytes in Media-containing Fluids from Different Size Class Follicles

Studies were conducted to investigate the effect of supplementation of fluid from different sized class [small (SFF, < 3 mm), medium (MFF, 3-8 mm) and large (LFF, > 8 mm)] of normal and cystic (CFF) ovarian follicles in oocyte culture media on oocyte maturation rate and embryo development in vitro and to test the efficacy of follicular fluid (FF) from different size classes as a whole oocyte maturation medium. Results suggested that FF were capable of developing buffalo oocytes to embryonic stage in vitro although its efficacy was lower than that of serum. Regardless of high maturation rates after in vitro maturation (IVM) in media containing FF or IVM in whole FF, low blastocyst rates were obtained after in vitro fertilization (IVF) and culture of embryos. Follicular fluid from small follicles had significantly (p < 0.05) higher potential of developing buffalo oocytes to embryonic stage in vitro than that from medium and large follicles. Cystic FF was not capable of supporting development of buffalo oocytes in vitro.     

The Challenge of Ecophysiological Biodiversity for Biotechnological Applications of Marine Microalgae

In this review, we aim to explore the potential of microalgal biodiversity and ecology for biotechnological use. A deeper exploration of the biodiversity richness and ecophysiological properties of microalgae is crucial for enhancing their use for applicative purposes. After describing the actual biotechnological use of microalgae, we consider the multiple faces of taxonomical, morphological, functional and ecophysiological biodiversity of these organisms, and investigate how these properties could better serve the biotechnological field. Lastly, we propose new approaches to enhancing microalgal growth, photosynthesis, and synthesis of valuable products used in biotechnological fields, mainly focusing on culture conditions, especially light manipulations and genetic modifications.     

Role of Clostridium perfringens in causing abomasal ulcers in buffalo

In this study, the correlation between abomasal ulcers and presence of Clostridium perfringens (C. perfringens) was evaluated in 80 (50 affected and 30 non affected) randomly slaughtered buffaloes in Ahvaz slaughterhouse. Immediately after the slaughter, the abomasums was isolated and an incision was made on the wall of it. Then the abomasums were emptied and its interior was washed with water. The inner surface was examined for presence of abnormal lesion. Ulcers from affected and piece of abomasa from non affected buffaloes were cultured. Cultures were also made from contents of all samples and smears were also prepared from affected and non affected tissues. Cultures from content samples (12%) of 50 ulcerated abomasa were positive for C. perfringens while the agents were isolated from 1 content (3.3%) of non ulcerated abomasa. There was no statistical difference between presence of C. perfringens in contents and abomasal ulcers. Totally C. perfringens were isolated from ulcers of 6 (12%) ulcerated and tissues of 3 (10%) non ulcerated cases. Statistical analysis showed no correlation between presences of C. perfringens and abomasal ulcers. There was no statistical difference between sex and age of the affected animals. In conclusion C. perfringens seems not to be solely, a cause ofabomasal ulcers in buffaloes.     

Early Innate Immune Response of Mannose‐binding Lectin and Lysozyme in Juvenile Channel Catfish,Ictalurus punctatus

Innate immune proteins mannose‐binding lectin (MBL) and lysozyme were studied in channel catfish, Ictalurus punctatus, during two consecutive years at 2, 4, 6, 9, and 12 mos of age. Both groups maintained in indoor tanks in light/dark photoperiod at mean temperature 27 C. Dot‐blot enzyme linked immunosorbent assay (ELISA) for MBL and turbidometry lysozyme assay done to quantify the two innate proteins and means determined for two consecutive years. An increase in mean MBL was seen in 4‐mo catfish (26.9 ± 0.8 µg/mL) when compared with all other age groups. A decrease in mean MBL was seen in 6‐ and 9‐mo catfish when compared with all other age groups. Both 2‐mo (21 ± 1.4 µg/mL) and 12‐mo (19.9 ± 0.4 µg/mL) catfish were very similar in mean MBL concentrations. The greatest increase in mean lysozyme was seen at 4 mo (15 ± 5.0 µg/mL). Juvenile channel catfish could produce lysozyme at 2 mo equivalent to lysozyme concentrations found in 9‐ and 12‐mo catfish. The greatest increases for MBL and lysozyme were seen in 4‐mo catfish. Mean total protein of 26.7 mg/mL and mean albumin/globulin ratio of 0.7 were found for the two groups of channel catfish sera.     

Pesticides‐non target plants interactions: An overview

Pesticides are widely used for crop protection in agriculture, plantation and forestry. Pesticides, when sprayed or dusted in the fields, only a small amount fall directly on the target organisms due to the small size and mobility of the pests. Most of them come to the soil or to the plants by direct precipitation or spray drift. Plants growing in the contaminated soil take up these chemicals along with water and mineral nutrients and translocate them to the aerial parts. Pesticides fallen on the leaf surface may find their way inside through leaf cuticle, stomata, hydrathodes, lenticels or tissues in the bark. Several factors influence pesticide uptake by plants. Pesticides are highly toxic chemicals and may not be absolutely specific in their actions. Impact of pesticide on plant depends upon its absorption, translocation and metabolism within the plant. Pesticides are usually detoxified in plants through series of degradation reactions and conjugation processes forming bound or insoluble residues. Failing to do so, plants show phytotoxic effects. Pesticides may affect different physiological processes in plants vital to their normal growth. They may also alter genetic materials in plants inducing gene mutation, chromosomal aberrations and chromosome break influencing their physiology and growth. Interaction of pesticides and their degradation products with non‐target plants is discussed here on different areas of research that are of particular interest in the context of this discussion.