Physiological And Molecular Response Of Strawberry Plants Under Exogenous Phenolic Acid Stress

Continuous cropping obstacle is a serious problem in the facility production of strawberry.In this study,the changes of the membrane and the internal structure in root mitochondria are observed by means of electron microscopy,and the subcellular characteristics of strawberry in responding to allelopathy effect are also studied by measuring the level of phosphorylation,the activities of electron transportation and photosynthetic electron transport,and photo damaging.High throughput transcriptome sequencing and bioinformatics analysis are used to identify the target genes responding to allelopathy effect among the differential expression genes relating to mitochondria function,and then verify the function of those target genes.The results are used to discuss the potential responding mechanism of mitochondria in strawberry roots to allelopathy effect mediating by phenolic acid,which has theoretical and practical significance for promoting the sustainable development of strawberry industries.The main results are as follows:1.The growth and biomass of different species and the treatment of exogenous phenolic acids in response to different leaf dipping treatment on plant growth was stronger inhibition,and the effect was shown as the treatment of syringic acid>syringic acid+phthalic acid two formic acid treatment>phthalic acid treatment.2.The two treatments of 3 phenolic acids all inhibited the photosynthesis of strawberry plants.It showed that Pn,Gs,Ci and WUE were significantly lower than those of control,the contents of chlorophyll and Chl.a,Chl.b and Chl.a+b were reduced in different degrees.The photosynthetic parameters of VPSI index was significantly increased,VPSI+PSII index were significantly lower than the control,V_j,W_k and F_v/F_m increased and PI_ABS decreased.3.Although all treatments increased the respiratory rate of COX pathway,but the change was not significant,while the AOX pathway increased significantly under exogenous phenolic acid stress,which showed that the efficiency of leaf soaking respiration was higher than that of root irrigation.4.The application of three exogenous phenolic acids can lead to a significant decrease in root activity,and with the prolongation of processing time,root activity showed a significant downward trend,and the activities of H⁺-ATPase,K⁺Na⁺-ATPase and Ca²⁺Mg²⁺-ATPase decreased to some extent.5.Under normal culture conditions,H₂O₂ and O₂^-content in roots was very low,root watering treatment,compared with control,H₂O₂ and O₂^-levels were elevated in different degrees,treatment D>treatment D+L>treatment L.6.A mixture of exogenous syringic acid,phthalic acid and two kinds of treatments were decreased,POD,CAT and SOD root APX activity and gene expression,increase MPTP,reduce theΔψm and root mitochondrial cytochrome Cyt c/a content,and ultimately reduce mitochondrial function.7.Under exogenous phenolic acid stress,the root respiration rate decreased significantly,while EMP-TCA based approaches,the contribution rate was significantly reduced,while the PPP approach showed obvious increasing trend of EMP,the activities of the respiratory key enzymes were inhibited with the prolongation of the stress time,which led to the obstruction of the respiratory pathways.8.The results of differential expression gene clustering and KEGG showed that 149 with the Rubisco photosynthetic enzyme genes involved,67 oxidative phosphorylation and mitochondrial membrane metabolism related genes were down regulated;the other were down regulated genes involved in the respiratory metabolism of 42 and 35 with mitochondrial EMP and TCA.