Strigolactones （SLs） are a novel class of plant hormones and rhizosphere communication signals, although the molecular mechanisms underlying their activities have not yet been fully determined. Nor is their applicat...Strigolactones （SLs） are a novel class of plant hormones and rhizosphere communication signals, although the molecular mechanisms underlying their activities have not yet been fully determined. Nor is their application in agriculture well developed. The importance of plant hormone agonists has been demonstrated in both basic and applied research, and chemicals that mimic strigolactone functions should greatly facilitate strigolactone research. Here, we report our discovery of a new phenoxyfuranone compound, 4-Br debranone （4BD）, that shows similar activity to that of the major strigolactone （SL） analog GR24 in many aspects of a biological assay on plants. 4BD strongly inhibited tiller bud outgrowth in the SL-deficient rice mutant d10 at the same concentration as GR24, with no adverse effects, even dur- ing prolonged cultivation. This result was also observed in the Arabidopsis thaliana SL-deficient mutants max1, max3, and max4. However, the application of 4BD to the Arabidopsis SL-insensitive mutant max2 induced no morphological changes in it. The expression of SL biosynthetic genes was also reduced by 4BD treatment, probably via negative feed- back regulation. However, in a seed germination assay on Striga hermonthica, a root parasitic plant, 4BD showed far less activity than GR24. These results suggest that 4BD is the first plant-specific strigolactone mimic.展开更多
Strigolactones(SLs)are plant hormones that regulate the branching of plants and seed germination stimulants of root parasitic plants.As root parasites are a great threat to agricultural production,the use of SL agonis...Strigolactones(SLs)are plant hormones that regulate the branching of plants and seed germination stimulants of root parasitic plants.As root parasites are a great threat to agricultural production,the use of SL agonists could be anticipated to provide an efficient method for regulating root parasites as suicidal germination inducers.A series of phenoxyfuranone-type SL mimics,termed debranones,has been reported to show potent bioactivities,including reduction of the tiller number on rice,and stimulation of seed germination in the root parasite Striga hermonthica.To exert both activities,two substituents on the phenyl ring of the molecules were important but at least a substituent at the 2-position must be an electron-withdrawing group.However,little is known about the effect of the properties of the substituents at the 2-position on bioactivities.Here,we found that different substituents at the 2-position give different preferences for bioactivities.Halogenated debranones were more effective than the others and SL agonist GR24 for inhibiting rice tiller but far less effective in the induction of S.hermonthica germination.Meanwhile,nitrile and methyl derivatives clearly stimulated the germination of S.hermonthica seeds.Although their IC_(50) values were 100 times higher than that of GR24 in the receptor competitive binding assay,their physiological activities were approximately 1/10 of GR24.These differences could be due to their uptake in plants and/or their physicochemical stability under our experimental conditions.These findings could support the design of more potent and selective SL agonists that could contribute to solving big agricultural issues.展开更多
文摘Strigolactones （SLs） are a novel class of plant hormones and rhizosphere communication signals, although the molecular mechanisms underlying their activities have not yet been fully determined. Nor is their application in agriculture well developed. The importance of plant hormone agonists has been demonstrated in both basic and applied research, and chemicals that mimic strigolactone functions should greatly facilitate strigolactone research. Here, we report our discovery of a new phenoxyfuranone compound, 4-Br debranone （4BD）, that shows similar activity to that of the major strigolactone （SL） analog GR24 in many aspects of a biological assay on plants. 4BD strongly inhibited tiller bud outgrowth in the SL-deficient rice mutant d10 at the same concentration as GR24, with no adverse effects, even dur- ing prolonged cultivation. This result was also observed in the Arabidopsis thaliana SL-deficient mutants max1, max3, and max4. However, the application of 4BD to the Arabidopsis SL-insensitive mutant max2 induced no morphological changes in it. The expression of SL biosynthetic genes was also reduced by 4BD treatment, probably via negative feed- back regulation. However, in a seed germination assay on Striga hermonthica, a root parasitic plant, 4BD showed far less activity than GR24. These results suggest that 4BD is the first plant-specific strigolactone mimic.
基金partly supported by a grant from the Core Research for Evolutional Science and Technology(CREST)Program of the Japan Science and Technology Agency(JST)the Japan International Cooperation Agency(JICA)+1 种基金JST under a joint program of Science and Technology Research Partnership for Sustainable Development(SATREPS)a JSPS Grant-in-Aid for Scientific Research(Grant no.18H03939 to TA).
文摘Strigolactones(SLs)are plant hormones that regulate the branching of plants and seed germination stimulants of root parasitic plants.As root parasites are a great threat to agricultural production,the use of SL agonists could be anticipated to provide an efficient method for regulating root parasites as suicidal germination inducers.A series of phenoxyfuranone-type SL mimics,termed debranones,has been reported to show potent bioactivities,including reduction of the tiller number on rice,and stimulation of seed germination in the root parasite Striga hermonthica.To exert both activities,two substituents on the phenyl ring of the molecules were important but at least a substituent at the 2-position must be an electron-withdrawing group.However,little is known about the effect of the properties of the substituents at the 2-position on bioactivities.Here,we found that different substituents at the 2-position give different preferences for bioactivities.Halogenated debranones were more effective than the others and SL agonist GR24 for inhibiting rice tiller but far less effective in the induction of S.hermonthica germination.Meanwhile,nitrile and methyl derivatives clearly stimulated the germination of S.hermonthica seeds.Although their IC_(50) values were 100 times higher than that of GR24 in the receptor competitive binding assay,their physiological activities were approximately 1/10 of GR24.These differences could be due to their uptake in plants and/or their physicochemical stability under our experimental conditions.These findings could support the design of more potent and selective SL agonists that could contribute to solving big agricultural issues.
