Strigolactones positively regulate chilling tolerance in pea and in Arabidopsis

Abstract

Strigolactones (SL) fulfil important roles in plant development and stress tolerance. Here, we characterized the role of SL in the dark chilling tolerance of pea and Arabidopsis by analysis of mutants that are defective in either SL synthesis or signalling. Pea mutants (rms3, rms4, and rms5) had significantly greater shoot branching with higher leaf chlorophyll a/b ratios and carotenoid contents than the wild type. Exposure to dark chilling significantly decreased shoot fresh weights but increased leaf numbers in all lines. Moreover, dark chilling treatments decreased biomass (dry weight) accumulation only in rms3 and rms5 shoots. Unlike the wild type plants, chilling-induced inhibition of photosynthetic carbon assimilation was observed in the rms lines and also in the Arabidopsis max3-9, max4-1, and max2-1 mutants that are defective in SL synthesis or signalling. When grown on agar plates, the max mutant rosettes accumulated less biomass than the wild type. The synthetic SL, GR24, decreased leaf area in the wild type, max3-9, and max4-1 mutants but not in max2-1 in the absence of stress. In addition, a chilling-induced decrease in leaf area was observed in all the lines in the presence of GR24. We conclude that SL plays an important role in the control of dark chilling tolerance.

Strigolactones in plant adaptation to abiotic stresses: An emerging avenue of plant research

“…The control over this phenotypic plasticity via SLs indicates that they have the potential to enable plants to avoid deleterious effects from severe drought by reducing vegetative growth and by also saving energy for subsequent reproductive development. By using SL mutants of pea (SL‐synthetic rms3 and SL‐signalling rms4 ) and Arabidopsis (SL‐synthetic max3 and max4 , and SL‐signalling max2 ), Cooper et al () recently demonstrated the roles of SLs in protecting photosynthesis under dark chilling conditions, thereby enhancing shoot biomass production. In addition, SLs also act as a positive regulator of leaf senescence by enabling plants to reallocate the nutrients from old tissues to developing younger tissues (Yamada & Umehara, ).…”

“…Thus, an important area of research has emerged to further elucidate the roles of SLs in plant stress adaptation. Because SLs have already been proven to be responsive to drought, salinity, and chilling (Cooper et al, ; C. V. Ha et al, ; W. Li et al, ; Liu et al, ; Visentin et al, ; Y. Zhang et al, ), it would be interesting to investigate how SLs adjust osmotic imbalance and oxidative stress by regulating the formation of compatible solutes and antioxidant components.…”

“…These findings collectively provided important clues regarding the potential of SLs in regulating plant responses and adaptation to environmental stresses. Thus, an increasing number of studies have recently focused on the implications of SLs in the adaptation of plants to environmental constraints and have reported many novel findings (Bu et al, ; Cooper et al, ; C. V. Ha et al, ; Liu et al, ; Lv et al, ; Ma et al, ; Ruiz‐Lozano et al, ; Umehara et al, ; Visentin et al, ; Y. Zhang, Lv, & Wang, ). Moreover, the connection of SLs in AM symbiosis‐mediated improvement of physiological responses has also been reported in plants under abiotic stresses, such as high salinity and drought (Aroca et al, ; Ruiz‐Lozano et al, ).…”

Comparing and Contrasting the Multiple Roles of Butenolide Plant Growth Regulators: Strigolactones and Karrikins in Plant Development and Adaptation to Abiotic Stresses

“…In recent years, substantial evidence has demonstrated that SLs and KARs are involved in the regulation of the plant responses to abiotic stress [8,37,38,[41][42][43]46,63,143,190,191] (Table 1). SL levels are finely modulated under various types of abiotic stress.…”

“…SLs also promote beneficial symbiotic relationships between host plants and mycorrhizal fungi [35,36]. The biosynthesis and signaling of SLs are regulated by various abiotic stress factors [37][38][39][40], including the recently reported SL involvement in responding to nutrient deprivation, drought, chilling and salinity [38,[40][41][42][43][44][45][46][47][48][49][50]. Such studies provide new insights into the novel roles SL signaling plays in the regulation of plant adaptation to adverse environmental conditions [51][52][53][54].Karrikins (KARs) are found in smoke released from the heating or combustion of plant material, after which they can stimulate the germination of dormant seeds [55][56][57][58].…”