TY  - EJOU
AU  - Correa-Aguado, Hans Christian 
AU  - Cerrillo-Rojas, Gloria Viviana 
AU  - Rocha-Uribe, Alejandro 
AU  - Soria-Guerra, Ruth Elena 
AU  - Morales-Domínguez, José Francisco 

TI  - Benzyl Amino Purine and Gibberellic Acid Coupled to Nitrogen-Limited Stress Induce Fatty Acids, Biomass Accumulation, and Gene Expression in <i>Scenedesmus Obliquus</i>
T2  - Phyton-International Journal of Experimental Botany

PY  - 2021
VL  - 90
IS  - 2
SN  - 1851-5657

AB  - The need for renewable energy sources makes microalgae an essential feedstock for biofuels production. The molecular aspects and the response to nitrogen (N)-limited conditions with a phytohormone stimulus in microalgae have been slightly explored. In this work, <i>Scenedesmus obliquus</i> was used as a study model to analyze the effect of benzyl amino purine (BAP) and gibberellic acid (GA) coupled to nitrogen limitation on cell growth, biomass and fatty acids. The selected 10<sup>-5</sup> M BAP increased the biomass by 1.44-fold, and 10<sup>-6</sup> M GA by 1.35-fold. The total lipids also increased by 2.8 and 1.11-fold, respectively. The 10<sup>-5</sup> M BAP and <br/>10<sup>-6</sup> M GA addition to <i>S. obliquus</i> cultures at different initial nitrogen percentages (N-0, N-25, and N-50) showed a significant increase in cell growth and biomass productivity compared to the unstimulated cultures. BAP N-0 and GA N-0 produced the highest lipid yields with 55% and 50%, respectively. The lipid profile analysis revealed an increase, particularly in C18:1 and C16:0 fatty acids. Gene expression analysis showed an over-expression of acyl carrying protein (<i>ACP)</i>, stearoyl-ACP desaturase <i>(SAD)</i>, fatty acid acyl-ACP thioesterase <i>(FATA)</i>, and diacylglycerol acyltransferase (<i>DGAT</i>) genes, which were mainly induced by nitrogen limitation. Furthermore, BAP and GA produced a significant over-expression on these genes in the N-replete cultures. This study shows that BAP and GA, coupled to N limitation stress, can be used to increase the biomass and lipid production in <i>S. obliquus</i> for sustainable biofuels.
KW  - Biodiesel; gene expression; lipids; microalgae; nitrogen deficiency; phytohormones

DO  - 10.32604/phyton.2021.013619