The effects of the phytohormone strigolactone(SL)and smoke-derived karrikins(KARs)on plants are generally distinct,despite the fact that they are perceived through very similar mechanisms.The homologous receptors DWAR...The effects of the phytohormone strigolactone(SL)and smoke-derived karrikins(KARs)on plants are generally distinct,despite the fact that they are perceived through very similar mechanisms.The homologous receptors DWARF14(D14)and KARRIKIN-INSENSITIVE2(KAI2),together with the F-box protein MORE AXILLARY GROWTH2(MAX2),mediate SL and KAR responses,respectively,by targeting different SMAX1-LIKE(SMXL)family proteins for degradation.These mechanisms are putatively well-insulated,with D14-MAX2 targeting SMXL6,SMXL7,and SMXL8 and KAI2-MAX2 targeting SMAX1 and SMXL2 in Arabidopsis thaliana.Recent evidence challenges this model.We investigated whether D14 can target SMAX1 and whether this occurs naturally.Genetic analysis indicates that the SL analog GR24 promotes D14-SMAX1 crosstalk.Although D14 shows weaker interactions with SMAX1 than with SMXL2 or SMXL7,D14 mediates GR24-induced degradation of SMAX1 in plants.Osmotic stress triggers SMAX1 degradation,which is protective,through SL biosynthesis and signaling genes.Thus,D14-SMAX1 crosstalk may be beneficial and not simply a vestige of the evolution of the SL pathway.展开更多
基金We gratefully acknowledge funding support from US National Science Foundation(NSF)grants IOS-1737153,IOS-1740560,and IOS-1856741 to D.C.NSpanish Ministry of Science and Innovation grants BIO2017-84363-R and PID2020-112779RB-I00 and FESF Investing in Your Future to P.C.
文摘The effects of the phytohormone strigolactone(SL)and smoke-derived karrikins(KARs)on plants are generally distinct,despite the fact that they are perceived through very similar mechanisms.The homologous receptors DWARF14(D14)and KARRIKIN-INSENSITIVE2(KAI2),together with the F-box protein MORE AXILLARY GROWTH2(MAX2),mediate SL and KAR responses,respectively,by targeting different SMAX1-LIKE(SMXL)family proteins for degradation.These mechanisms are putatively well-insulated,with D14-MAX2 targeting SMXL6,SMXL7,and SMXL8 and KAI2-MAX2 targeting SMAX1 and SMXL2 in Arabidopsis thaliana.Recent evidence challenges this model.We investigated whether D14 can target SMAX1 and whether this occurs naturally.Genetic analysis indicates that the SL analog GR24 promotes D14-SMAX1 crosstalk.Although D14 shows weaker interactions with SMAX1 than with SMXL2 or SMXL7,D14 mediates GR24-induced degradation of SMAX1 in plants.Osmotic stress triggers SMAX1 degradation,which is protective,through SL biosynthesis and signaling genes.Thus,D14-SMAX1 crosstalk may be beneficial and not simply a vestige of the evolution of the SL pathway.
