Phylogenetic diversity and predictive functional profile of bacteria associated with marine microalgae, Isochrysis galbana using next generation sequencing- Supplementary Data

In aquaculture, microalgal-bacterial interaction has ecological significance, and thus demands better understanding for improvement of sustainability and productivity of large scale microalgal cultivation. Here, we assessed the bacterial diversity, including the uncultivable bacterial assemblage associated with the marine microalgae Isochrysis galbana using next generation sequencing approach. Isochrysis has been considered as one of the most favoured types of live feed in aquaculture and hence, chose Isochrysis galbana MBTDCMFRI S002. Total genomic DNA was extracted from I. galbana culture and 16S rDNA V3 region was sequenced with an Illumina MiSeq platform. A total of 30 different known bacterial genera were detected from 1190 identified operational taxonomic units. These bacterial phylotypes were affiliated to Alphaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Actinobacteria, Acidimicrobiia, Bacteroidia, Flavobacteriia and Bacilli classes. These 30 bacterial genera comprise only 4.62% of the total OTUs obtained and remaining 95.38% of the sequences do not exhibit any similarity against known bacterial genera in the taxonomic database. The functional profile of bacterial communities was predicted using PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) analysis. The results indicated that these associated bacterial communities are mainly involved in environmental as well as genetic information processing, membrane transport and nutrient metabolism. These functions may mediate their interaction with the phytoplankton host, and thus improve bacterial survival in microalgal habitat. Overall, the present study enhances the understanding of microalgal-bacterial interaction in terms of diversity and functional role of associated microbial community.

Phylogenetic diversity and predictive functional profile of bacteria associated with marine microalgae, Isochrysis galbana using next generation sequencing

In aquaculture, microalgal-bacterial interaction has ecological significance, and thus demands better understanding for improvement of sustainability and productivity of large scale microalgal cultivation. Here, we assessed the bacterial diversity, including the uncultivable bacterial assemblage associated with the marine microalgae Isochrysis galbana using next generation sequencing approach. Isochrysis has been considered as one of the most favoured types of live feed in aquaculture and hence, chose Isochrysis galbana MBTDCMFRI S002. Total genomic DNA was extracted from I. galbana culture and 16S rDNA V3 region was sequenced with an Illumina MiSeq platform. A total of 30 different known bacterial genera were detected from 1190 identified operational taxonomic units. These bacterial phylotypes were affiliated to Alphaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Actinobacteria, Acidimicrobiia, Bacteroidia, Flavobacteriia and Bacilli classes. These 30 bacterial genera comprise only 4.62% of the total OTUs obtained and remaining 95.38% of the sequences do not exhibit any similarity against known bacterial genera in the taxonomic database. The functional profile of bacterial communities was predicted using PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) analysis. The results indicated that these associated bacterial communities are mainly involved in environmental as well as genetic information processing, membrane transport and nutrient metabolism. These functions may mediate their interaction with the phytoplankton host, and thus improve bacterial survival in microalgal habitat. Overall, the present study enhances the understanding of microalgal-bacterial interaction in terms of diversity and functional role of associated microbial community.

Isolation and characterization of high quality DNA from marine benthic macroalgae.

The isolation of high quality DNA is essential for many molecular biology applications including polymerase chain reaction (PCR) and endonuclease restriction digestion based techniques. An easy and inexpensive protocol has been developed for extracting genomic DNA from seven species of algae viz. Lola capillaries, Enteromorpha intestinalis, Ulva lactuca and Rhizoclonium sp belonging to Chlorophyceae, Catenella nipae, Polysiphonia mollis belonging to Rhodophyceae and Dictyota ceylanica belonging to Phaeophyceae group were collected from the coastal regions of Sunderban delta in West Bengal, India dominantly growing on mud flats, bark of different mangrove trees, pneumatophores, stilt roots, concrete surfaces, wooden and bamboo poles, sides of the boats and other water vehicles inundated during high tides. The DNA was found suitable for restriction endonuclease digestion and PCR amplification with randomely amplified polymorphic DNA (RAPD) primers. The A260/A280 ratio of 1.15 0.14 to 1.94 indicated little contamination from proteins and polysaccharides. The PCR amplification with RAPD primers showed its suitability in PCR based techniques and the restriction digestion with Eco RV confirmed its suitability for hybridization based techniques. The protocol is equally good for isolating DNA from both fresh as well as preserved materials.

Plant regeneration from leaf explants of mulberry: influence of sugar, genotype and 6-benzyladenine.

A protocol for plant regeneration from leaf explants was developed for tropical mulberry varieties. Effect of sugars, 6-benzyladenine and genotype on shoot regeneration was studied. Highest percentage of shoot regeneration (80 +/- 6) was obtained with genotype S799 on medium containing glucose and 8.9 microM 6-benzyladenine. Genotypes Mandalaya and MIHP, having thicker leaves with waxy cuticle, showed poorer regeneration ability than S799 and Sujanpur-5, which have thinner leaves and cuticle. Histological studies revealed that shoots regenerated from sub-epidermal cells.