Mitochondrial phylogeography reveals high haplotype diversity and unique genetic lineage in Indian dugongs (Dugong dugon)

1. India plays a significant role in dugong conservation by having the largest population within South Asia. The status of dugongs in India is largely unknown due to a paucity of reliable ecological data. This study generated mitochondrial control region sequences from ~10% of dugong individuals from existing populations within India. Furthermore, data generated in this study were compared with the global data to assess genetic lineages, population structure, and genetic diversity of Indian populations.
2. Multiple analyses suggest that the Indian dugong populations are part of a single genetic cluster, comprising South Asia, North-west Indian Ocean, and South-west Indian Ocean populations. Despite small population size, they retain high genetic diversity with unique mitochondrial DNA haplotypes within South Asia. Within India, novel haplotypes are observed from all dugong habitats sampled, with overall high haplotype diversity (0.85 ± 0.04) but low nucleotide diversity (0.005 ± 0.001). Indian populations exhibit genetic differentiation with higher within-population variance (63.41%) than among populations (36.59%). Two of the haplotypes observed in India are shared with Sri Lanka, implying genetic connectivity between these populations.
3. The genetic data from Indian dugong populations provide critical insights into the identification of dugong corridors and important dugong conservation zones in India. We suggest site-specific interventions, including the creation of new marine protected areas and boundary reorganization and expansion of other existing protected areas, to ensure population connectivity. In addition, simultaneous efforts towards seagrass meadow restoration, reduction of dugong mortalities, and community participation in dugong conservation are recommended for population recovery of this threatened marine herbivore.

     

Synergistic effect of root-associated bacteria on plant growth and certain physiological parameters of banana plant (Musa acuminata)

Fifty strains of bacteria isolated from banana roots were studied for their plant growth promoting (PGP) activities. Indole -3- acetic acid (IAA) production by root-associated bacteria ranged from 20 to 302 µg ml^?1. Seventeen isolates (34%) were positive for siderophore production and 18 isolates (36%) showed phosphate solubilization. None of the isolates showed potassium solubilization. All the isolates showed growth on nitrogen free Jensen medium. Identification of the bacteria based on 16S rRNA gene sequencing revealed that the isolates belonged to genus Bacillus sp, Klebsiella sp, Microbacterium sp and Enterobacter sp. A pot experiment in a greenhouse was conducted to investigate the effect PGP bacteria on banana plant growth and enzyme activities. The results demonstrated a significant (P < 0.05) increase in plant growth, chlorophyll, total phenolics, proline, catalase and ascorbic acid oxidase in banana plants treated with PGP bacteria as compared to control. However, the plant-growth response was variable and dependent on the bacterial strains, enzyme activity, and growth parameter observed. The present study revealed that bacteria showing multiple PGP activity could be used as biostimulants in enhancing banana production.