National Agricultural Research Centre

About: National Agricultural Research Centre is a based out in . It is known for research contribution in the topics: Population & Gene. The organization has 1230 authors who have published 1263 publications receiving 25389 citations.

Soil beneficial bacteria and their role in plant growth promotion: a review

Abstract: Soil bacteria are very important in biogeochemical cycles and have been used for crop production for decades. Plant–bacterial interactions in the rhizosphere are the determinants of plant health and soil fertility. Free-living soil bacteria beneficial to plant growth, usually referred to as plant growth promoting rhizobacteria (PGPR), are capable of promoting plant growth by colonizing the plant root. PGPR are also termed plant health promoting rhizobacteria (PHPR) or nodule promoting rhizobacteria (NPR). These are associated with the rhizosphere, which is an important soil ecological environment for plant–microbe interactions. Symbiotic nitrogen-fixing bacteria include the cyanobacteria of the genera Rhizobium, Bradyrhizobium, Azorhizobium, Allorhizobium, Sinorhizobium and Mesorhizobium. Free-living nitrogen-fixing bacteria or associative nitrogen fixers, for example bacteria belonging to the species Azospirillum, Enterobacter, Klebsiella and Pseudomonas, have been shown to attach to the root and efficiently colonize root surfaces. PGPR have the potential to contribute to sustainable plant growth promotion. Generally, PGPR function in three different ways: synthesizing particular compounds for the plants, facilitating the uptake of certain nutrients from the soil, and lessening or preventing the plants from diseases. Plant growth promotion and development can be facilitated both directly and indirectly. Indirect plant growth promotion includes the prevention of the deleterious effects of phytopathogenic organisms. This can be achieved by the production of siderophores, i.e. small metal-binding molecules. Biological control of soil-borne plant pathogens and the synthesis of antibiotics have also been reported in several bacterial species. Another mechanism by which PGPR can inhibit phytopathogens is the production of hydrogen cyanide (HCN) and/or fungal cell wall degrading enzymes, e.g., chitinase and s-1,3-glucanase. Direct plant growth promotion includes symbiotic and non-symbiotic PGPR which function through production of plant hormones such as auxins, cytokinins, gibberellins, ethylene and abscisic acid. Production of indole-3-ethanol or indole-3-acetic acid (IAA), the compounds belonging to auxins, have been reported for several bacterial genera. Some PGPR function as a sink for 1-aminocyclopropane-1-carboxylate (ACC), the immediate precursor of ethylene in higher plants, by hydrolyzing it into α-ketobutyrate and ammonia, and in this way promote root growth by lowering indigenous ethylene levels in the micro-rhizo environment. PGPR also help in solubilization of mineral phosphates and other nutrients, enhance resistance to stress, stabilize soil aggregates, and improve soil structure and organic matter content. PGPR retain more soil organic N, and other nutrients in the plant–soil system, thus reducing the need for fertilizer N and P and enhancing release of the nutrients.

Flavonoid composition of fruit tissues of citrus species.

Abstract: An HPLC analysis was performed on the concentrations of flavonoids in 42 species and cultivars of the Citrus genus and those of two Fortunella and one Poncirus species according to the classification system established by Tanaka. The composition of 8 flavanones and 9 flavone/ols for these species was determined in the albedo, flavedo, segment epidermis and juice vesicle tissues, and those in the fruit and peel tissues were calculated from the composition data of the tissues. A principal component analysis showed that such neohesperidosyl flavonoids as neoeriocitrin, naringin, neohesperidin, and rhoifolin had large factor loading values in the first principal component for each tissue. The flavonoid composition of citrus fruits was approximately the same within each section of Tanaka’s system, except for the species in the Aurantium section and those with a peculiar flavonoid composition such as Bergamot (C. bergamia), Marsh grapefruit (C. paradisi), Sour orange (C. aurantium), and Shunkokan (C. shunkokan)...

Mutually beneficial pollinator diversity and crop yield outcomes in small and large farms

Abstract: Ecological intensification, or the improvement of crop yield through enhancement of biodiversity, may be a sustainable pathway toward greater food supplies. Such sustainable increases may be especially important for the 2 billion people reliant on small farms, many of which are undernourished, yet we know little about the efficacy of this approach. Using a coordinated protocol across regions and crops, we quantify to what degree enhancing pollinator density and richness can improve yields on 344 fields from 33 pollinator-dependent crop systems in small and large farms from Africa, Asia, and Latin America. For fields less than 2 hectares, we found that yield gaps could be closed by a median of 24% through higher flower-visitor density. For larger fields, such benefits only occurred at high flower-visitor richness. Worldwide, our study demonstrates that ecological intensification can create synchronous biodiversity and yield outcomes.

Proposal of Lysinibacillus boronitolerans gen. nov. sp. nov., and transfer of Bacillus fusiformis to Lysinibacillus fusiformis comb. nov. and Bacillus sphaericus to Lysinibacillus sphaericus comb. nov.

Abstract: Three strains of a spore-forming, Gram-positive, motile, rod-shaped and boron-tolerant bacterium were isolated from soil. The strains, designated 10a(T), 11c and 12B, can tolerate 5 % (w/v) NaCl and up to 150 mM boron, but optimal growth was observed without addition of boron or NaCl in Luria-Bertani agar medium. The optimum temperature for growth was 37 degrees C (range 16-45 degrees C) and the optimum pH was 7.0-8.0 (range pH 5.5-9.5). A comparative analysis of the 16S rRNA gene sequence demonstrated that the isolated strains were closely related to Bacillus fusiformis DSM 2898(T) (97.2 % similarity) and Bacillus sphaericus DSM 28(T) (96.9 %). DNA-DNA relatedness was greater than 97 % among the isolated strains and 61.1 % with B. fusiformis DSM 2898(T) and 43.2 % with B. sphaericus IAM 13420(T). The phylogenetic and phenotypic analyses and DNA-DNA relatedness indicated that the three strains belong to the same species, that was characterized by a DNA G+C content of 36.5-37.9 mol%, MK-7 as the predominant menaquinone system and iso-C(15 : 0) (32 % of the total) as a major cellular fatty acid. In contrast to the type species of the genus Bacillus, the strains contained peptidoglycan with lysine, aspartic acid, alanine and glutamic acid. Based on the distinctive peptidoglycan composition, phylogenetic analyses and physiology, the strains are assigned to a novel species within a new genus, for which the name Lysinibacillus boronitolerans gen. nov., sp. nov. is proposed. The type strain of Lysinibacillus boronitolerans is strain 10a(T) (=DSM 17140(T)=IAM 15262(T)=ATCC BAA-1146(T)). It is also proposed that Bacillus fusiformis and Bacillus sphaericus be transferred to this genus as Lysinibacillus fusiformis comb. nov. and Lysinibacillus sphaericus comb. nov., respectively.

Micronutrient constraints to crop production in soils with Mediterranean-type characteristics: A review

Abstract: Mediterranean-type soils generally have free CaCO3, high pH, and low organic matter. Consequently, nutrient disorders in these soils are the most important limiting factor to crop production, secon...