Strigolactones Biosynthesis and Their Role in Abiotic Stress Resilience in Plants: A Critical Review

Abstract

Strigolactones (SLs), being a new class of plant hormones, play regulatory roles against abiotic stresses in plants. There are multiple hormonal response pathways, which are adapted by the plants to overcome these stressful environmental constraints to reduce the negative impact on overall crop plant productivity. Genetic modulation of the SLs could also be applied as a potential approach in this regard. However, endogenous plant hormones play central roles in adaptation to changing environmental conditions, by mediating growth, development, nutrient allocation, and source/sink transitions. In addition, the hormonal interactions can fine-tune the plant response and determine plant architecture in response to environmental stimuli such as nutrient deprivation and canopy shade. Considerable advancements and new insights into SLs biosynthesis, signaling and transport has been unleashed since the initial discovery. In this review we present basic overview of SL biosynthesis and perception with a detailed discussion on our present understanding of SLs and their critical role to tolerate environmental constraints. The SLs and abscisic acid interplay during the abiotic stresses is particularly highlighted.Main Conclusion: More than shoot branching Strigolactones have uttermost capacity to harmonize stress resilience.

Sugar availability suppresses the auxin‐induced strigolactone pathway to promote bud outgrowth

“…We highlight that sugar supply inhibits strigolactone response to promote bud outgrowth. Strigolactones inhibit bud outgrowth and mediate the effect of auxin (Beveridge et al, 2000;Zou et al, 2006;Hayward et al, 2009) as well as the response to different abiotic stresses that modulate strigolactone synthesis (phosphate or nitrogen deficiency) or signalling (drought) (Umehara et al, 2010;Kohlen et al, 2011;Bu et al, 2014;Ha et al, 2014;Saeed et al, 2017). We show that sugar supply is able to repress the inhibitory effect of strigolactones on buds, as is the case for strigolactone-induced bamboo leaf senescence in the dark (Tian et al, 2018).…”

“…As mentioned above, high sugar levels may explain a reduction in apical dominance in response to environmental or genetic factors that increase the source-sink balance within the plant. In addition to sugar, cytokinins and strigolactones have been shown to be involved in branching in response to several environmental factors (Takei et al, 2002;Drummond et al, 2015;Roman et al, 2016;Saeed et al, 2017). We suggest that our network involving auxin, sugars, cytokinins and strigolactones may be a key integrator of the plant growth status and environmental conditions, to dynamically adapt plant architecture and therefore contribute to plant plasticity.…”

Sugar availability suppresses the auxin-induced strigolactone pathway to promote bud outgrowth

“…We highlight that sugar supply inhibits strigolactone response to promote bud outgrowth. Strigolactones inhibit bud outgrowth and mediate the effect of auxin (Beveridge et al , 2000; Zou et al , 2006; Hayward et al , 2009) as well as the response to different abiotic stresses which modulate strigolactone synthesis (phosphate or nitrogen deficiency) or signaling (drought) (Umehara et al , 2010; Kohlen et al , 2011; Bu et al , 2014; Ha et al , 2014; Saeed et al , 2017). We show that sugar supply is able to repress the inhibitory effect of strigolactones on buds, as it is the case for strigolactone-induced bamboo leaf senescence in dark (Tian et al , 2018).…”

“…It has been suggested that sucrose could promote bud outgrowth in a signaling manner in rose and pea (Barbier et al , 2015b; Fichtner et al , 2017) and further experiments are required to determine the molecular mechanisms underlying the interactions between sugar availability and auxin. In addition to sugar, cytokinins and strigolactones have been shown to be involved in the response of branching to several environmental factors (Takei et al , 2002; Drummond et al , 2015; Roman et al , 2016b; Saeed et al , 2017). We suggest that our network involving auxin, sugars, cytokinins, and strigolactones may be a key integrator of the plant growth status and environmental conditions, to dynamically adapt plant architecture and thus contribute to plant plasticity.…”

The Role of Dwarfing Traits in Historical and Modern Agriculture with a Focus on Rice

“…A well-known correlation between plant height and tiller number exists in rice (Yan et al 1998;Li et al 2003), and rice mutants in SL synthesis and signaling typically display both reduced stature and increased tillering (Kinoshita and Shinbashi 1982;Kinoshita and Takahashi 1991). It is therefore not surprising that SL biosynthesis has been proposed as a target for breeding (Yoneyama et al 2012;Saeed et al 2017).…”