| Sunflower broomrape is the most serious parasitic weed threatening sunflower production worldwide,which infects sunflower roots and causes serious yield and economic losses.In this study,43 sunflower germplasm resources were identified for resistance,and s41 material(resistant)and s26 material(susceptible)were used as test materials.Based on the physiological responses of susceptible and resistant materials to Broomrape infestation,and transcriptome studies were conducted to reveal the physiological and biochemical characteristics and molecular mechanisms under broomrape infestation,the main findings were as follows:(1)Among 43 sunflower germplasm resources,a total of four resistance classes of highly resistant,resistant,susceptible and highly susceptible materials were identified,and no immune materials were identified.29 materials,including s06 and s41 for highly resistant materials,s43 for resistant materials,s01,s02,s03,s04,s05,s07 and s08 for susceptible materials,and s14,s17,s19,s20 for highly susceptible materials s23,s24,s25,s26 and other11 materials,the parasitism degree of high resistance grade 0.20 and 0.15,parasitism rate of13.33% and 7.69%,respectively;resistance grade 0.27,parasitism rate of 18.18%,respectively;the parasitism degree of susceptible grade between 1.65 and 9.82,parasitism rate between 53.33% and 100.00%,high susceptible The parasitism level of susceptible grade ranged from 1.65 to 9.82,and the parasitism rate ranged from 53.33% to 100.00%,while the parasitism rate of high susceptible grade ranged from 10.58 to 16.25,and the parasitism rate was 100.00%.(2)Paraffin sections of susceptible materials showed that the cell walls of parasitized sunflower roots were not observed to thicken significantly when compared with those of non-parasitized roots,i.e.,the parasitized sunflower roots did not cause corkiness of cells in the outer cortex.When Lepidoptera crossed the outer cortex and inner cortex to reach the vascular bundle,the parasitic process of Lepidoptera caused corkiness of the cell wall of the inner cortex cells.The formation of suction apparatus starts only when the endothelial layer is reached,and multiple shoot tubes are formed when the sunflower roots are parasitized by broomrape.(3)The physiological indexes of both the highly resistant material and the highly susceptible material were higher than the control under the inoculation of Leptospermum.In the highly resistant material,glutathione content,phenylalanine aminolytic enzyme activity and salicylic acid content were 37.00%,118.01% and 96.33% higher than the control,respectively.The differences of phenylalanine deaminase,cinnamyl alcohol dehydrogenase,ascorbyl peroxidase activity and salicylic acid content in the high-sensitive material were all highly significant compared with the high-sensitive material,with 99.35%,52.76% and17.89% higher than the resistant material,respectively,and 52.76% higher than the highsensitive material in the salicylic acid content.(4)In the metabolic pathways of salicylic acid,lignin synthesis,glutathione synthesis,and cork synthesis,analysis of the s26-vs-s41 comparative group revealed that the genes for the disease-course-related protein PR-1,phenylalanine deaminase,glutathione-S-transferase,and CYP86 enzyme genes,on the other hand,showed down-regulation,indicating that the genes for these enzymes were more highly expressed in the highly resistant material,and the genes for phosphoglucose-1-dehydrogenase,and glutathione peroxidase genes showed upregulation,indicating higher expression in the high-sensitive material.Analysis of the s26-vs-s26 CK and s41-vs-s41 CK comparison groups revealed that the genes for NPR1,F5 H,and glutathione peroxidase were heavily expressed in the susceptible and resistant materials under broomrape inoculation.Analysis of s26CK-vs-s41 CK revealed that NPR1,disease process-related protein PR-1,glutathione-S-transferase gene,and CYP86 enzyme gene showed down-regulation,indicating that the expression of these genes was higher in the resistant material under the treatment of no inoculation with broomrape.(5)GO functional enrichment analysis showed that biological processes were mainly cellular processes,developmental processes,metabolic processes,and biological regulation;cellular components were mainly cellular,cellular parts,organelles,membranes,and organelle parts;in terms of molecular functions,binding,catalytic activity,and transporter proteins were dominant.Levantine parasitism mainly affects the cell wall,cell membrane,peroxidase,KEGG pathway enrichment analysis shows that Levantine parasitic sunflower mainly affects sugar metabolism,amino acid metabolism,lipid metabolism,secondary metabolite biosynthesis,signal transduction,folding,sorting and degradation,translation,energy metabolism,transport metabolic pathway,Levantine parasitic under mainly affects the phenylpropanoid biosynthesis of sense and resistance materials,phyto hormone signaling,plant MAPK signaling pathway,zeatin,carotenoid biosynthesis and other metabolic pathways.(6)For the analysis of differentially expressed genes,the up-regulated differentially expressed genes of the susceptible and resistant materials affected basically the same processes under the inoculation broomrape when conditions,including sunflower phytohormones,water channel proteins,plant drought resistance,plant cell defense responses,etc.The down-regulated expressed genes of the susceptible and resistant materials were different,and the down-regulated genes of the highly susceptible materials mainly affected plant drought resistance,regulation of water dissipation,water channel proteins,growth hormone transport pathogenesis The down-regulated genes of high-sensitive materials mainly affected the processes of drought resistance,regulation of water dispersal,water channel proteins,growth hormone transport pathogenesis,and lipid metabolism,while the down-regulated differentially expressed genes of high-resistant materials mainly affected the processes of C/N and ABC transport,cytochrome P450,unipodal ipid synthesis,and MAPK signaling in plants. |
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