Dr Erina Sulistiani, SEAMEO BIOTROP Senior Supervisor at Product Development and Services Department, obtained her doctoral degree in plant biology from the Graduate School of Bogor Agricultural University (IPB) on 28 August 2018. In line with her interest and expertise, Dr Erina used the title of “Agrobacterium tumefaciens-Mediated Genetic Transformation of Kappaphycus alvarezii Using Gα Gene to Obtain Hyposaline Tolerance” for her dissertation, which was supervised by Prof Suharsono, Dr Ence Darmo Jaya Supena and Dr Miftahudin.
Kappaphycus alvarezii is an important macroalgae species from phylum Rhodophyta which produces carrageenan that is widely used by food, medicine and cosmetic industries. This seaweed optimally grows at salinity of 28-34 ppt. However, due to lower salinity of the seawater during the rainy season, the seaweed often suffers hyposaline stress which leads to its susceptibility to disease.
“My supervisors and I would like to find a solution for overcoming the hyposaline stress of this seaweed. We explored the possibility of Gα gene to obtain a transgenic Cottonii seaweed which hyposaline tolerant,” said Dr Erina.
Gα gene, which is an α subunit of G protein, plays an important role in regulation of calcium ion channel in the plasma membrane of the cell. Under hyposaline condition, Gα protein maintains potassium/natrium homeostasis by increasing external calcium influx to the cytoplasm. Increased calcium content could increase the rigidity of cell walls to reduce excess water influx into the cytoplasm during hyposaline stress. The calcium itself also plays a role in reducing the loss of ions during influx of water by decreasing the permeability of plasma membrane to other ions.
According to Dr Erina, her research was conducted in three steps. First, the seaweed was co-cultivated with Agrobacterium tumefaciens which carried Gα expression vector. Then, the growth of non-transgenic and transgenic plantlets was observed in the medium with normal salinity (30 ppt) and hyposalinity (15 and 20 ppt) for 5 weeks. The last step was the analysis of the Gα gene expression of transgenic plantlets that were tolerant to low salinity condition.
“From the research results, we found that the genetic transformation of the Cottonii seaweed using Gα gene mediated by Agrobacterium tumefaciens had produced Cottonii seaweed transgenic plantlets that overexpressed Gα gene and had a higher tolerance to hyposaline stress than that of non-transgenic plantlets,” she concluded. These results have been and are being processed to be published in BIOTROPIA journal.
Dr Erina hopes that in the future the transgenic Cottonii seaweed plantlets developed by her team can pass the Genetically Modified Organism (GMO) test so that it can be utilized by communities.