Study on gender differences between male and female Sargassum thunbergii based on metabolomic analysis and physiological functions

Abstract

The impact of human activities on global climate change has led to the intensification of multiple environmental stresses on intertidal zone macroalgae, which are crucial primary producers in marine ecosystems. Despite their economic and ecological importance, research on the differential response mechanism of male and female macroalgae has been limited to gender differentiation. This study investigated gender differences in carbon and nitrogen metabolism of male and female Sargassum thunbergii based on metabolomic and physiological experiments. Carbon and nitrogen metabolism, as the most essential processes of macroalgae, coupled with basic metabolites transporting and energy supplying for macroalgal growth and development. The results revealed that female macroalgae exhibited higher activity in the carbon metabolic pathway, with fixed carbon being more inclined towards allocation to lipid synthesis and the TCA cycle. The overrepresentation of the TCA cycle and lipid synthesis metabolism made the female S. thunbergii store a large amount of energy, which consequently assured them to complete the reproductive stages. Conversely, the male macroalgae were more active in nitrogen metabolic pathways, such as nitrogen fixation and glutamate metabolism, which contribute to the growth and development of the macroalgae and increase resistance to the external environment. These dichotomous strategies likely exemplify distinct reproductive adaptations, where females focus on reproductive investment and males prioritize personal vigor and adaptation to external pressures. These findings provide new insights into gender differences in physiological characteristics and carbon and nitrogen metabolism processes of macroalgae, and contribute to the study of differential response mechanisms of male and female macroalgae in adaptation to intertidal environments, energy and material allocation mechanisms.