Strigolactone Involvement in Root Development, Response to Abiotic Stress, and Interactions with the Biotic Soil Environment

Abstract

Strigolactones, recently discovered as plant hormones, regulate the development of different plant parts. In the root, they regulate root architecture and affect root hair length and density. Their biosynthesis and exudation increase under low phosphate levels, and they are associated with root responses to these conditions. Their signaling pathway in the plant includes protein interactions and ubiquitin-dependent repressor degradation. In the root, they lead to changes in actin architecture and dynamics as well as localization of the PIN-FORMED auxin transporter in the plasma membrane. Strigolactones are also involved with communication in the rhizosphere. They are necessary for germination of parasitic plant seeds, they enhance hyphal branching of arbuscular mycorrhizal fungi of the Glomus and Gigaspora spp., and they promote rhizobial symbiosis. This review focuses on the role played by strigolactones in root development, their response to nutrient deficiency, and their involvement with plant interactions in the rhizosphere.

Arbuscular mycorrhizal symbiosis induces strigolactone biosynthesis under drought and improves drought tolerance in lettuce and tomato

“…As mentioned previously, AM symbiosis establishment requires a finely regulated molecular dialogue between the two partners, in which SLs have arisen as essential cues (Bucher et al , , Gutjahr & Parniske, , López‐Ráez et al , ). It is well known that SL production is promoted by nutrient deficiency, mainly phosphorus starvation (López‐Ráez et al , , Yoneyama et al , ) to promote AM fungal development and symbiosis establishment (Andreo‐Jiménez et al , , Kapulnik & Koltai, ). In addition to nutritional stress, an increased SL production in the presence of R. irregularis under salt stress was proposed in lettuce (Aroca et al , ).…”

On the substrate specificity of the rice strigolactone biosynthesis enzyme DWARF27

“…Strigolactones (SLs) are a class of plant hormones (Gomez-Roldan et al 2008;Umehara et al 2008) that modulate the shape of plants in response to environmental conditions, by regulating different developmental processes, such as shoot branching and formation of lateral roots (de Saint et al 2013;Kapulnik and Koltai 2014;Seto and Yamaguchi 2014;Waldie et al 2014;Al-Babili and Bouwmeester 2015). SLs were first isolated from root exudates based on the capability to induce seed germination in root parasitic weeds of the genus Striga (Cook et al 1966;Xie et al 2010).…”

Strigolactone biosynthesis is evolutionarily conserved, regulated by phosphate starvation and contributes to resistance against phytopathogenic fungi in a moss, Physcomitrella patens

“…Subsequently, several developmental functions have been attributed to SLs, including induction of secondary growth, determining root architecture by inhibiting the growth of primary roots, and triggering the growth of lateral roots and root hairs. In addition, SLs accelerate senescence and are involved in the response of plants to abiotic stress (Brewer et al, 2013;Kapulnik & Koltai, 2014;Waldie et al, 2014;Al-Babili & Bouwmeester, 2015).…”