Effects Of Strigolactones Research Articles

Effects of exogenous strigolactone on the cadmium accumulation in Galinsoga parviflora Cav.

ABSTRACT Strigolactone can improve the tolerance of plants to abiotic stress. To improve the phytoremediation capacity of cadmium (Cd) hyperaccumulator Galinsoga parviflora Cav., the effects of strigolactone (using strigolactone analog GR24 with the concentration of 1 and 2 μmol/L) on the Cd accumulation of G. parviflora were studied. Cd treatment at 0.1 mg/L inhibited the growth of G. parviflora. Under Cd stress (0.1 mg/L), GR24 had no significant effect on the biomass and catalase activity of G. parviflora, while it decreased the peroxidase activity and increased the superoxide dismutase activity. In addition, GR24 decreased the root Cd content and root Cd extraction. GR24 at 1 μmol/L increased the shoot Cd content, shoot Cd extraction, bioconcentration factor, and translocation factor, while at 2 μmol/L, the opposite effect was observed. When the concentration of GR24 was 1 μmol/L, the shoot Cd content and shoot Cd extraction increased by 8.75% and 12.35%, respectively, compared with control. Moreover, correlation and grey relational analyses showed that the translocation factor, shoot Cd content, and plant height were the top three most highly correlated parameters with the shoot Cd extraction. These findings suggest that GR24 at 1 μmol/L can improve the phytoremediation capacity of G. parviflora for Cd.

Insights into strigolactone (GR24) mediated regulation of cadmium-induced changes and ROS metabolism in Artemisia annua

Agricultural soil contamination and subsequently crops still require alternative solutions to reduce associated environmental risks. The effects of strigolactones (SLs) in alleviating cadmium (Cd) phytotoxicity in Artemisia annua plants were investigated during this study. Strigolactones play a vital role during plant growth and development due to their complex interplay during a plethora of biochemical processes. However, information on the potential of SLs to elicit abiotic stress signaling and trigger physiological modifications in plants is limited. In order to decipher the same, A. annua plants were exposed to different concentrations of Cd (20 and 40 mg kg-1), with or without the supplementation of exogenous SL (GR24, a SL analogue) at 4 µM concentration. Under Cd stress, excess Cd accumulation resulted in reduced growth, physio-biochemical traits, and artemisinin content. However, the follow-up treatment of GR24 maintained a steady state equilibrium between reactive oxygen species and antioxidant enzymes, improved chlorophyll fluorescence parameters such as Fv/Fm, ФPSII, and ETR for improved photosynthesis, enhanced chlorophyll content, maintained chloroplast ultrastructure, improved the glandular trichome (GT) attributes and artemisinin production in A. annua. Moreover, it also resulted in improved membrane stability, reduced Cd accumulation, and regulated the behaviour of stomatal apertures for better stomatal conductance under Cd stress. The results of our study suggest that GR24 could be highly effective in alleviating Cd-induced damages in A. annua. It acts via the modulation of the antioxidant enzyme system for redox homeostasis, protection of the chloroplasts and pigments for improved photosynthetic performance, and improved GT attributes for enhanced artemisinin production in A. annua.

The effects of strigolactones on some biochemical traits in calcified media on grapevine

Plants are stressed in different ways when they are in environments unsuitable for them. Among these stresses, abiotic factors are common. Calcified soil is also a stress factor. In this type of soil, there are problems with the nutrient intake of the plant, nutrient deficiencies, or toxicity. In a stress environment, plants try to survive by reacting differently. One of these reactions is that plants increase the synthesis of phenolic compounds. These compounds perform various physiological functions in adapting to environmental problems. It is known that the reactions of plants to stress are associated with endogenous hormones. One of these hormones is strigolactone (SL), which is produced in plant roots and introduced as a new generation of hormones. In this study, the effects of SL applications in grapevine grown in calcified environments were examined with regard to the content of phenolic compounds and mineral element intake. ‘Hasandede’ grape variety grafted on 1103 P American rootstock were grown in environments containing control, 10% and 25% calcium oxide (CaO) and applied with SL (control, 1, 3 and 5 μM) in different doses. Total phenolic compounds were found statistically much higher especially in the majority of plants applied with 3 μM and 5 μM SL is considered to be the effect of SLs in stress prevention. It was concluded that mineral compounds intakes generally responded positively to SL applications. These results are considered to prove the effects of SLs on plant nutrition physiology and stress tolerance.

Effects of Strigolactone on Torreya grandis Gene Expression and Soil Microbial Community Structure Under Simulated Nitrogen Deposition.

Nitrogen enters the terrestrial ecosystem through deposition. High nitrogen levels can affect physical and chemical properties of soil and inhibit normal growth and reproduction of forest plants. Nitrogen modulates the composition of soil microorganisms. Strigolactones inhibits plant branching, promotes root growth, nutrient absorption, and promotes arbuscular fungal mycelia branching. Plants are subjected to increasing atmospheric nitrogen deposition. Therefore, it is imperative to explore the relationship between strigolactone and nitrogen deposition of plants and abundance of soil microorganisms. In the present study, the effects of strigolactone on genetic responses and soil microorganisms of Torreya grandis, under simulated nitrogen deposition were explored using high-throughput sequencing techniques. T. grandis is a subtropical economic tree species in China. A total of 4,008 differentially expressed genes were identified in additional N deposition and GR24 treatment. These genes were associated with multiple GO terms and metabolic pathways. GO enrichment analysis showed that several DEGs were associated with enrichment of the transporter activity term. Both additional nitrogen deposition and GR24 treatment modulated the content of nutrient elements. The content of K reduced in leaves after additional N deposition treatment. The content of P increased in leaves after GR24 treatment. A total of 20 families and 29 DEGs associated with transporters were identified. These transporters may be regulated by transcription factors. A total of 1,402,819 clean reads and 1,778 amplicon sequence variants (ASVs) were generated through Bacterial 16S rRNA sequencing. Random forest classification revealed that Legionella, Lacunisphaera, Klebsiella, Bryobacter, and Janthinobacterium were significantly enriched in the soil in the additional N deposition group and the GR24 treatment group. Co-occurrence network analysis showed significant differences in composition of soil microbial community under different treatments. These results indicate a relationship between N deposition and strigolactones effect. The results provide new insights on the role of strigolactones in plants and composition of soil microorganisms under nitrogen deposition.

Effect of strigolactones on recruitment of the rice root-associated microbiome.

Strigolactones are endogenous plant hormones regulating plant development and are exuded into the rhizosphere when plants experience nutrient deficiency. There, they promote the mutualistic association of plants with arbuscular mycorrhizal fungi that help the plant with the uptake of nutrients from the soil. This shows that plants actively establish—through the exudation of strigolactones—mutualistic interactions with microbes to overcome inadequate nutrition. The signaling function of strigolactones could possibly extend to other microbial partners, but the effect of strigolactones on the global root and rhizosphere microbiome remains poorly understood. Therefore, we analyzed the bacterial and fungal microbial communities of 16 rice genotypes differing in their root strigolactone exudation. Using multivariate analyses, distinctive differences in the microbiome composition were uncovered depending on strigolactone exudation. Moreover, the results of regression modeling showed that structural differences in the exuded strigolactones affected different sets of microbes. In particular, orobanchol was linked to the relative abundance of Burkholderia–Caballeronia–Paraburkholderia and Acidobacteria that potentially solubilize phosphate, while 4-deoxyorobanchol was associated with the genera Dyella and Umbelopsis. With this research, we provide new insight into the role of strigolactones in the interplay between plants and microbes in the rhizosphere.

Enhancement of the photosynthetic and removal performance for microalgae-based technologies by co-culture strategy and strigolactone induction

In this study, digestate and biogas were treated simultaneously based on fungi-microalgae symbionts and fungi-microalgae-bacteria symbionts, respectively. The effects of strigolactone (GR24) on the biomass of symbionts and photosynthesis of algae, and purification of digestate and biogas were explored. With the induction of GR24, the metabolism of microorganism-microalgae systems and photosynthesis of microalgae were enhanced causing the rapid growth of the symbionts, further strengthening the purification performance of the systems. Moreover, the GR24 enhanced the CO2 removal performance of the co-culture systems via increasing the carbonic anhydrase activity of microalgae cells. The fungi-microalgae-bacteria co-culture strategy with GR24 induction was found to obtain great photosynthetic and removal performance, possessing the 73.54 ± 6.83% CO2 removal rate and 88.61 ± 8.24% COD removal rate.

Effects of strigolactone on photosynthetic and physiological characteristics in salt-stressed rice seedlings

Saline stress has been identified as the primary factor inhibiting rice seedling growth, which represents a complex abiotic stress process. Most plant hormones have been shown to alleviate the plant damage caused by salt stress. The effects of synthetic strigolactone (GR24) on Jinongda 667 rice seedlings treated with 200 mM NaCl were studied. Photosynthesis and its related physiological characteristics were analyzed in salt-stressed rice seedlings treated with GR24. NaCL stress inhibited the growth of the rice, including plant height and root length, by approximately 14% and 40%, respectively. Compared to the control check group (CK), the adverse effects of salt stress on the growth status, leaf photosynthesis, and physiological/biochemical indices in the rice seedlings were alleviated in the GR24 treatment group. With increases in the GR24 concentration, the plant height and root length of the seedlings increased. The plant height in the groups treated with 1/2 Hoagland’s complete nutrient solution + 200 mM NaCl +1 μM GR24 (T4) and 1/2 Hoagland’s complete nutrient solution + 200 mM NaCl +5 μM GR24 (T5) were significantly different than the 1/2 Hoagland’s complete nutrient solution + 200 mM NaCl group (T1) (P < 0.05), and there were significant differences between the T5 and T1 groups in root length (P < 0.05).The chlorophyll content in the rice seedling leaves was significantly different between the T1 group and all other groups (P < 0.05). The net photosynthetic rate of the T1 group was not significantly different from the T2 group (P > 0.05). The transpiration rate, stomatal conductance, and intercellular CO2 concentrations showed the same trends as the net photosynthetic rate. The MAD, POD, and SOD activities were significantly increased by 68%, 60%, 14%, respectively, compared to the CK group (P < 0.01). When the GR24 concentration was 1 μM, the rice seedlings were resistant to the adverse effects of high salt stress. Therefore, the addition of proper concentrations of GR24 could improve the rice yield in saline-alkali land.

Enhancement of lipid accumulation in Monoraphidium sp. QLY-1 by induction of strigolactone

In this study, the effects of strigolactone (SL) on the biomass, lipid content, biochemical properties, and gene transcription of Monoraphidium sp. QLY-1 were examined. The lipid content and lipid productivity increased by 61% and 55% in QLY-1 under 1 μM SL induction compared to the control group, respectively. SL also upregulated the levels of endogenous NO and Ca2+ and lipid biosynthesis gene transcription. Subsequently, the relationship between Ca2+ and nitric oxide (NO) in the regulation of cell growth and lipid accumulation of QLY-1 under SL induction conditions was analysed. An increase in endogenous Ca2+ regulated cell growth and lipid biosynthesis by modulating the levels of NO and lipid biosynthesis-related gene expression. Collectively, this study provided a valuable approach for biofuel production from microalgae under SL induction and demonstrated that there is crucial crosstalk between the Ca2+ and NO signalling in the manipulation of lipid biosynthesis in microalgae under SL treatment.

Alleviation of drought stress in grapevine by foliar-applied strigolactones

Drought is one of the major abiotic stress factors that affect grape growth and yield, which in turn negatively affects the grape and wine production industry. Developing effective approaches to improve grapevine tolerance to drought stress is a priority for viticulture. Strigolactones, a newly discovered class of carotenoid-derived phytohormones, have been found to participate in various physiological processes. Herein, the effect of strigolactones (SLs) on grape seedlings under drought stress was investigated. Two-year-old grape seedlings (Vitis vinifera L.) were sprayed with 3 doses of rac-GR24 (1 μM, 3 μM and 5 μM), a synthesized strigolactone, and then were subjected to 7% (w/v) polyethylene glycol (PEG-6000) to simulate the drought conditions. Synthetic GR24 treated plants showed higher tolerance to drought stress with regard to lower electrolyte leakage, stomatal opening, reactive oxygen species (ROS), and higher relative water content, chlorophyll content, photosynthesis rate and malondialdehyde (MDA) content. GR24 application also decreased the levels of indoleacetic acid (IAA) and zeatin riboside (ZR), while increasing the level of abscisic acid (ABA), both in the roots and leaves under drought stress. These results suggested that foliar application of GR24 could ameliorate the adverse effects of drought due to its regulation of stomatal closure through ABA or ROS, and modulation of chlorophyll components and photosynthesis, as well as activation of the antioxidant defense capacity. Cross-talk with other hormones, especially ABA, was also suggested to be one of the important mechanism during this process. This study contributes to our current understanding of GR24-induced drought tolerance in grapevines.

Effects of Strigolactones on Grain Yield and Seed Development in Rice

Strigolactones (SLs) are well known as a class of endogenous phytohormones that regulate tiller bud outgrowth. Reduction of inorganic phosphate (Pi) induces the accumulation of SLs, which inhibit tiller bud outgrowth in wild-type (WT) rice plants, but not in SL mutants. This suggests that SLs are important for plant adaptation to Pi-deficient conditions. Thus, we investigated the effects of SLs on grain yield and seed size in WT and dwarf (d) mutant rice plants treated with various Pi concentrations. In both WT and d mutants, plant growth, chlorophyll levels, panicle number, number of hulls, and total grain number decreased as Pi decreased, indicating that SL is not required to mediate these Pi responses. The d mutants produced more panicles than the WT control, but there was no increase in grain yield, and the seed-setting rate decreased. Removal of outgrowing tillers did not affect grain yield in d mutants. GR24 (a synthetic SL) treatment rescued grain yield in d mutants. The d3 and d53 mutants had the lowest grain yields among d mutants. Furthermore, the endosperm of d mutants was 25% smaller than that of WT plants; there were no significant differences in embryo length between WT and d mutant plants, but the endosperm cell area of the d mutants was approximately 30% smaller than that of WT plants. We propose that SLs control grain yield and rice endosperm development.

The role of strigolactones in photomorphogenesis of pea is limited to adventitious rooting.

The recently discovered group of plant hormones, the strigolactones, have been implicated in regulating photomorphogenesis. We examined this extensively in our strigolactone synthesis and response mutants and could find no evidence to support a major role for strigolactone signaling in classic seedling photomorphogenesis (e.g. elongation and leaf expansion) in pea (Pisum sativum), consistent with two recent independent reports in Arabidopsis. However, we did find a novel effect of strigolactones on adventitious rooting in darkness. Strigolactone-deficient mutants, Psccd8 and Psccd7, produced significantly fewer adventitious roots than comparable wild-type seedlings when grown in the dark, but not when grown in the light. This observation in dark-grown plants did not appear to be due to indirect effects of other factors (e.g. humidity) as the constitutively de-etiolated mutant, lip1, also displayed reduced rooting in the dark. This role for strigolactones did not involve the MAX2 F-Box strigolactone response pathway as Psmax2 f-box mutants did not show a reduction in adventitious rooting in the dark compared with wild-type plants. The auxin-deficient mutant bushy also reduced adventitious rooting in the dark, as did decapitation of wild-type plants. Rooting was restored by the application of indole-3-acetic acid (IAA) to decapitated plants, suggesting a role for auxin in the rooting response. However, auxin measurements showed no accumulation of IAA in the epicotyls of wild-type plants compared with the strigolactone synthesis mutant Psccd8, suggesting that changes in the gross auxin level in the epicotyl are not mediating this response to strigolactone deficiency.

Effect of strigolactones and auxins on growth and metabolite content of Sutherlandia frutescens (L.) R. Br. microplants in vitro

The influence of strigolactones as hormones in plants is not fully characterised even though they are known to affect plant architecture, both above ground and in the roots. Using an in vitro system, the effects of the synthetic auxins 1-naphthalene acetic acid and indole-3-butyric acid (NAA and IBA) and synthetic strigolactones (GR24 and Nijmegen-1) were tested on microplant development of Sutherlandia frutescens, a leguminous medicinal plant native to South Africa. Considerable phytochemical variation in wild populations has led to the proposal of using micropropagation for this species. This will assist with domestication and provide plants with a more predictable chemistry for the phytopharmaceuticals industry. Nodal explants with an axillary bud were grown on Murashige and Skoog (Plant Physiol 15:473–497, 1962) medium [0.8 % (m/v) agar (pH 5.8), 3 % (m/v) sucrose and 0.1 g/L myo-inositol] supplemented with NAA, IBA, GR24 and Nijmegen-1, either singly or in combination. The amino acid profile and secondary metabolite pool was monitored using LC–MS-profiling. Treatment with NAA promoted mass shoot production, whilst a combination of NAA and Nijmegen-1 also positively influenced the accumulation of amino acids, flavonoids (sutherlandins) and terpenoids (sutherlandiosides) that S. frutescens produces. Since these compounds represent the presumed active compounds in this species and the biomarkers used in quality control assessment of S. frutescens tissues harvested for the pharmaceutical industry, this treatment holds promise for the commercial production of Sutherlandia extracts and herbal medications.

Citlivost burinnych a divorastucich zaraz k syntetickemu analogu strigolaktonov GR24

Parasitic plants of genera Orobanche and Phelipanche germinate after exposition to chemical signals exuded by roots of the host plants. The most studied germination stimulants belong to strigolactones (SLs), the newly discovered plant hormones which are stimulating hyphal branching of arbuscular mycorrhizal fungi and are involved in regulation of shoot and root architecture of plants. However, little is known about the effect of strigolactones on germination of non-weedy broomrapes. The objective of our study was to investigate the sensitivity of seeds of non-weedy broomrapes to synthetic analogue of SLs, GR24. The seeds of non-weedy broomrapes Orobanche alba, O. alsatica, O. caryophyllacea, O. elatior, O. flava, O. lutea, O. pallidiflora, O. reticulata, Phelipanche arenaria, P. purpurea and weedy species P. ramosa were collected in natural and cropland plant communities in Slovakia. Seeds of P. ramosa and P. purpurea were highly sensitive to GR24. On the other hand, effectivity of GR24 in inducing germination of several wild species, O. alba, O. caryophyllacea and P. arenaria was low, while the stimulant shown to be completely not effective on other non-weedy species O. alsatica, O. elatior, O. flava, O. lutea, O. pallidiflora, and O. reticulata. The results point out there are differences in the requirement for germination signals that possibly depend on the host.

67. Effects of Strigolactone on Phosphate starvation response in arabidopsis

67. Effects of Strigolactone on Phosphate starvation response in arabidopsis

Flavonoids and strigolactones in root exudates as signals in symbiotic and pathogenic plant-fungus interactions.

Secondary plant compounds are important signals in several symbiotic and pathogenic plant-microbe interactions. The present review is limited to two groups of secondary plant compounds, flavonoids and strigolactones, which have been reported in root exudates. Data on flavonoids as signaling compounds are available from several symbiotic and pathogenic plant-microbe interactions, whereas only recently initial data on the role of strigolactones as plant signals in the arbuscular mycorrhizal symbiosis have been reported. Data from other plant-microbe interactions and strigolactones are not available yet. In the present article we are focusing on flavonoids in plant-fungal interactions such as the arbuscular mycorrhizal (AM) association and the signaling between different Fusarium species and plants. Moreover the role of strigolactones in the AM association is discussed and new data on the effect of strigolactones on fungi, apart from arbuscular mycorrhizal fungi (AMF), are provided.