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.     

Exclusion of Vibrio spp. by an antagonistic marine actinomycete Streptomyces rubrolavendulae M56

A marine actinomycete Streptomyces rubrolavendulae M56 isolated from the sediments of Bay of Bengal and displaying biogranulation property was used for the study. The strain showed antagonistic property against vibrios, the opportunistic pathogens in aquaculture. The efficacy of the biogranules of actinomycete M56 in competitive exclusion of Vibrio spp. was tested both in vitro and in vivo. Streptomyces rubrolavendulae M56 biogranules could significantly exclude the pathogenic Vibrio spp. in co‐culture experiments (in vitro). In vivo exclusion of Vibrio spp. in a Penaeus monodon postlarval rearing system was evaluated by treatment of the rearing water with biogranules of S. rubrolavendulae M56. The experiments proved that S. rubrolavendulae M56 biogranules could reduce the pathogenic Vibrio spp., while maintaining total heterotrophic bacterial count. Therefore, the actinomycete biogranules (M56) can be used as a promising alternative to antibiotics in the shrimp larval production system which is often affected by vibriosis.     

Photolysis of fluotrimazole

The major product identified in the photochemical degradation of fluotrimazole, in aqueous suspension, as a thin film on glass, and sprayed on barley leaves, was 3-(trifluoromethyl)triphenylmethanol. This was also detected after photolysis in methanol, although methyl 3-trifluoromethyltrityl ether was the major product. Moreover, under all these conditions, 3-(trifluoromethyl)triphenylmethane was also present. 3-Trifluoromethylbenzophenone was produced only by irradiation of an aqueous suspension. The photolysis products, in contrast to fluotrimazole, were inactive at 1 mmol against barley powdery mildew (Erysiphe graminis).     

Genetically-engineered crops and their effects on varietal diversity: a case of Bt eggplant in India

Building on the evidence from the impact of hybrid technology on varietal diversity loss, this paper explores ex ante the possible effects of introduction of Bt eggplant on on-farm varietal diversity of eggplant. The public–private partnership involved in the development and introduction of Bt eggplant provides a great opportunity to develop locally-adapted Bt open-pollinated varieties (OPVs) instead of having a limited number of generic hybrid varieties. The study shows that introduction of multiple Bt OPVs by public institutions will reduce the rate of replacement of OPVs by hybrids and thus help in conserving varietal diversity. However, the cost of developing multiple Bt OPVs is high; hence policy makers need to look at alternative measures to maintain the varietal diversity of crops such as eggplant in its centers of diversity.     

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.