Vigya Kesari

Development of Pongamia pinnata as an alternative biofuel crop — current status and scope of plantations in India

Pongamia pinnata is a leguminous tree known for its multipurpose benefits and as a potential source of biodiesel crop. Its added benefits to grow on marginal lands make it a suitable candidate in agro-forestry. These properties support the suitability of this plant for large-scale production required by a sustainable biodiesel industry. While utilizing these species as a source of biodiesel, there is a further need for research and extensive knowledge generation into various areas of production and utilization. The future success of P. pinnata as a sustainable source of biodiesel will heavily depend on an unlimited feed stock supply. This will call for large-scale plantations of clonal stocks of elite genotypes to encourage afforestation programs coordinated both at the central and state levels to cater to the needs of the biodiesel industry. The success rate will rely on the elite planting stock, propagation techniques, and plantation practices and models in making Pongamia cultivation an economically viable proposition.

Molecular marker-based characterization in candidate plus trees of Pongamia pinnata, a potential biodiesel legume.

Molecular marker studies provide valid guidelines for collection, characterization and selective cultivation of elite Pongamia germplasm that can be exploited further for its improvement through breeding and marker assisted selection for improved characters and oil yield towards biodiesel production.

Rhizobium pongamiae sp. nov. from root nodules of Pongamia pinnata.

Pongamia pinnata has an added advantage of N2-fixing ability and tolerance to stress conditions as compared with other biodiesel crops. It harbours “rhizobia” as an endophytic bacterial community on its root nodules. A gram-negative, nonmotile, fast-growing, rod-shaped, bacterial strain VKLR-01T was isolated from root nodules of Pongamia that grew optimal at 28°C, pH 7.0 in presence of 2% NaCl. Isolate VKLR-01 exhibits higher tolerance to the prevailing adverse conditions, for example, salt stress, elevated temperatures and alkalinity. Strain VKLR-01T has the major cellular fatty acid as C18:1   ω7c (65.92%). Strain VKLR-01T was found to be a nitrogen fixer using the acetylene reduction assay and PCR detection of a nifH gene. On the basis of phenotypic, phylogenetic distinctiveness and molecular data (16S rRNA, recA, and atpD gene sequences, G + C content, DNA-DNA hybridization etc.), strain VKLR-01T = (MTCC 10513T = MSCL 1015T) is considered to represent a novel species of the genus Rhizobium for which the name Rhizobium pongamiae sp. nov. is proposed. Rhizobium pongamiae may possess specific traits that can be transferred to other rhizobia through biotechnological tools and can be directly used as inoculants for reclamation of wasteland; hence, they are very important from both economic and environmental prospects.

Genetic diversity in ecotypes of the scarce wild medicinal crop Zingiber moran revealed by ISSR and AFLP marker analysis and chromosome number assessment

Zingiber moran, a rare ginger found only in a few parts of northeast India, faces the threat of extinction due to its exploitation as an important medicinal plant. In this study, the chromosome number of wild ecotypes of Z. moran was determined and the genetic analysis was carried out using two kinds of molecular markers: inter simple sequence repeats (ISSR) and amplified fragment length polymorphism (AFLP). A chromosome number of 2n = 22 was confirmed for all 10 ecotypes investigated. AFLP analysis revealed a greater amount of genetic polymorphism (95.06%), with a strong resolving power in detecting intraspecific variation, compared to ISSR analysis (34.61%). Genetic diversity parameters, such as number of observed alleles (na), mean number of effective alleles (ne), mean Neis gene diversity index (h), and Shannon index (I) for ISSR and AFLP were in the range 1.34–1.95, 1.25–1.60, 1.44–0.33, and 0.20–0.49, respectively. Marker indices and polymorphic information content varied from 0.5–19.3 and 0.03–0.27 for ISSR, and 28.2–39 and 0.3–0.39 for AFLP, respectively. Dendrograms derived by unweighted pair group method of arithmetic averages cluster analysis based on molecular data classified the ecotypes into two major clusters. The Mantel test cophenetic correlation coefficient (r) for ISSR (0.85) and AFLP (0.91) showed a good degree of confidence in the association with 10 ecotypes. Clustering was further supported by principle component analysis which demarcated individuals of hilly topography from the ones of plain land.

Genetic diversity and relationship of Hedychium from Northeast India as dissected using PCA analysis and hierarchical clustering

Molecular genetic fingerprints of eleven Hedychium species from Northeast India were developed using PCR based markers. Fifteen inter-simple sequence repeats (ISSRs) and five amplified fragment length polymorphism (AFLP) primers produced 547 polymorphic fragments. Positive correlation (r = 0.46) was observed between the mean genetic similarity and genetic diversity parameters at the inter-species level. AFLP and ISSR markers were able to group the species according to its altitude and intensity of flower aroma. Cophenetic correlation coefficients between the dendrogram and the original similarity matrix were significant for ISSR (r = 0.89) compared to AFLP (r = 0.83) markers. This genetic characterization of Hedychium from Northeast India contributes to the knowledge of genetic structure of the species and can be used to define strategies for their conservation and management.

Coordinated changes in storage proteins during development and germination of elite seeds of Pongamia pinnata, a versatile biodiesel legume

Seeds of Pongamia pinnata used as feedstock for biodiesel production and the protein-rich residue is fed to farm animals. This paper describes seed development and early germination in terms of phenology, protein and reserve accumulation and utilization. The findings will underpin rapid and successful exploitation of this promising energy and animal feed crop.

Antimicrobial and micro Raman spectroscopy of selected Zingiberaceae species from Northeast India

Antimicrobial activity of crude rhizome oils from some important members of Zingiberaceae from Northeast India was carried out in the present study. The plants used were Curcuma amada, C. longa, Zingiber moran, and Z. zerumbet. Rhizomes of the four species were collected and rhizome oil was extracted using six different polar and non-polar solvents. The antimicrobial property of the crude oil was studied against human pathogens using disc-diffusion and viability assay. The rhizome oil of all the 24 extracts exhibited potent antimicrobial activity against all pathogenic bacterial and fungal strains tested. Hydrodistilled fractions of the four species studied showed better effect among all solvents. Water extract of Z. moran was found to be the highest effective antimicrobial agent of all. Antibacterial effect of the water fractions was also characterized against Gram-positive and Gram-negative bacteria using micro Raman spectroscopy. This investigation shows that the essential oils from the wild and domestic species of the family Zingiberaceae from Northeast India are a potential source of bioactive compounds with tremendous medicinal, economic, and therapeutic value. The wild and endemic species Z. moran represents an interesting and promising source of plant-derived antimicrobial agent in the development of new drugs against pathogens.