外源独脚金内酯缓解蒙古黄芪干旱胁迫的生理与转录响应OA

To investigate the physiological and molecular mechanisms by which exogenous strigolactone(SL)alleviates drought stress in Astragalus membranaceus var.mongholicus,a pot experiment with controlled watering was conducted using Astragalus membranaceus var.mongholicus as the material.4 treatments were established:normal water supply(control),drought stress,drought stress+foliar application of 0.5 μmol/L SL,and drought stress+foliar application of 5 μmol/L SL.Physiological in-dicator measurements combined with RNA-Seq transcriptome sequencing were employed to systemat-ically analyze the effects of exogenous SL on the physiological characteristics and gene expression reg-ulation of Astragalus membranaceus var.mongholicus under drought stress.The results showed that drought stress significantly inhibited the growth and photosynthesis of Astragalus membranaceus var.mongholicus and aggravated membrane lipid peroxidation damage.Exogenous SL effectively alleviated the damage caused by drought in Astragalus membranaceus var.mongholicus.Specifically,the 0.5μmol/L SL treatment mainly induced the activation of WRKY and bHLH transcription factors,syn-ergistically promoting α-linolenic acid metabolism and flavonoid biosynthesis,thereby strengthening the antioxidant defense system of the plants.In contrast,the 5 μmol/L SL treatment significantly upregu-lated the expression of MYB-related transcription factors,promoted the repair of photosynthesis-antenna pro-tein-related pathways and enhanced glutathione metabolism,and synergistically increased polysaccharide accu-mulation,thereby facilitating the transition of plants from stress defense to growth recovery.In conclusion,exogenous SL could mediate specific transcription factor regulatory networks to activate either the antioxidant defense system or photosynthetic system repair pathways,constructing a multi-dimensional response mecha-nism of Astragalus membranaceus var.mongholicus in response to drought stress.