Open Access

ARTICLE

Benzyl Amino Purine and Gibberellic Acid Coupled to Nitrogen-Limited Stress Induce Fatty Acids, Biomass Accumulation, and Gene Expression in Scenedesmus Obliquus

Hans Christian Correa-Aguado^1,3, Gloria Viviana Cerrillo-Rojas¹, Alejandro Rocha-Uribe², Ruth Elena Soria-Guerra², José Francisco Morales-Domínguez^1,*

1 Departamento de Química, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, 20131, México
2 Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, San Luis Potosí, 78210, México
3 Instituto Politécnico Nacional, Unidad Profesional Interdisciplinaria de Ingeniería Campus Zacatecas, Blvd. del Bote 202, Cerro del Gato Ejido La Escondida, Col. Ciudad Administrativa, Zacatecas, ZAC 98160, Mexico

* Corresponding Author: José Francisco Morales-Domínguez. Email:

Phyton-International Journal of Experimental Botany 2021, 90(2), 515-531. https://doi.org/10.32604/phyton.2021.013619

Received 13 August 2020; Accepted 15 October 2020; Issue published 07 February 2021

Abstract

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, Scenedesmus obliquus 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^-5 M BAP increased the biomass by 1.44-fold, and 10^-6 M GA by 1.35-fold. The total lipids also increased by 2.8 and 1.11-fold, respectively. The 10^-5 M BAP and
10^-6 M GA addition to S. obliquus 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 (ACP), stearoyl-ACP desaturase (SAD), fatty acid acyl-ACP thioesterase (FATA), and diacylglycerol acyltransferase (DGAT) 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 S. obliquus for sustainable biofuels.

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