Beyond a neurotransmitter: The role of serotonin in plants

Abstract

Serotonin is a neurotransmitter than has been identified across all forms of life. In recent years the presence and function of serotonin in plants (phytoserotonin) is becoming an increasingly active area of research. Serotonin has been found to function as a plant growth regulator, and a stress defense molecule. Through these functions serotonin has been implicated in mediation of morphogenesis, vegetative growth, reproductive development, seed germination and survival, abiotic and biotic stress survival and mediation of plant signaling and mediation of plant cycles. Despite its widespread importance in plants there is still very little understood about the mechanism of action of this important signaling molecule in plants, therefore, this review provides a brief overview of the roles and mechanisms of serotonin in the plant system.

Serotonin and Melatonin Biosynthesis in Plants: Genome-Wide Identification of the Genes and Their Expression Reveal a Conserved Role in Stress and Development

“…The multifunctional roles of Mel in plants and the recent discovery of the first plant Mel receptor has led to emerging speculations of Mel acting as a new phytohormone or master regulator [24]. Likewise, Ser also plays diverse roles in plants, with its functions in stress response being delineated in the last decade [7,25,26].…”

Serotonin: A frontline player in plant growth and stress responses

“…Thus, serotonin functions as a natural antioxidant in senescent tissue and may postpone senescence‐induced oxidative damage in plants as well as protect the integrity of vascular components by permitting nutrient mobilization (Erland & Saxena, 2017; Kang, Kim, et al, 2009). Furthermore, serotonin has been reported to play a crucial role in bud maturity and ovule development in Datura metel (Erland & Saxena, 2017). Moreover, serotonin has been shown to play a crucial role in stage transition in H. perforatum during the early stages of reproduction.…”

“…As a result, the component responsible for gamete compatibility is essential for the early development of reproductive incompatibilities across identical or similar species (Harper & Hart, 2005). Pollen allelopathy has been previously shown to play an important role in fertilization success and gamete compatibility (Erland et al, 2016; Erland & Saxena, 2017; Erland, Turi, & Saxena, 2019; Roshchina, 2001, 2005, 2006; Roshchina & Melnikova, 1998). Serotonin has been implicated in pollen allelopathy, and the evidence suggests that it could play a role in microspore formation by modulating cyclic adenosine monophosphate (cAMP) signalling (Erland et al, 2016; Roshchina, 2001).…”

“…In rice, the content of serotonin is increased up to 700‐fold in senescent leaves (Kang, Park, et al, 2009; Negri et al, 2021). Thus, serotonin functions as a natural antioxidant in senescent tissue and may postpone senescence‐induced oxidative damage in plants as well as protect the integrity of vascular components by permitting nutrient mobilization (Erland & Saxena, 2017; Kang, Kim, et al, 2009). Furthermore, serotonin has been reported to play a crucial role in bud maturity and ovule development in Datura metel (Erland & Saxena, 2017).…”

“…The circadian clock regulates various aspects of plant growth and development in diverse plant species (Eckstein et al, 2021; Sakuraba, 2021; Yakir et al, 2007). Serotonin has been proposed as a crucial messenger and a potent modulator of phytochrome signalling (Erland & Saxena, 2017; Roychoudhury, 2021). Compared to red light‐exposed protoplasts, serotonin treatment improves calcium uptake in dark‐grown protoplasts (Das & Sopory, 1985; Erland et al, 2016).…”