The Role Of 2,5-dihydroxyphenylacetic Acid Involved In Resistance To Wheat Stripe Rust

Wheat stripe rust caused by a specialized parasitic fungus,Puccinia striiformis f.sp.tritici(Pst),is a global problem for wheat production.Currently,the use of diseaseresistant varieties is considered to be the most economical,environmentally friendly and efficient means,but the breeding rate of disease-resistant varieties is often slower than the mutation rate of Pst.Meanwhile,the application of synthetic chemicals in the long-term pose risks to both the environment and pathogen resistance.Previous studies have shown that plants employ natural compounds in their defense mechanism.Thus,exploring natural molecule compounds that provide durable resistance against stripe rust in wheat is essential.In this experiment,we utilized metabolomic and transcriptomic analysis to investigate changes in the synthesis of specific metabolites and related genes during resistance to Pst,by studying the incompatible interaction of Suwon 11 and Pst CYR23.Our techniques included data mining,integrated analysis,Agrobacterium-mediated transient expression,virus-mediated gene silencing,highperformance liquid chromatography(HPLC),and q RT-PCR.Through this,we have uncovered the metabolomic and transcriptomic responses of the wheat and Pst interaction,which lays out a solid foundation for delineating the molecular mechanism of wheat’s resistance to Pst.The results of our study offer insights into natural compounds that can aid in controlling and managing stripe rust in wheat for the long term.The main findings are as follows:1.Integrated analysis clarified the involvement of HGA in the wheat-Pst interaction process: The infestation of Su11 by Pst CYR23 resulted in 76 significant differential metabolites,with the highest number produced at 24 hpi.Further trend analysis exhibited an increasing trend in several significant differential metabolites,including 2-aminoadipic acid,histidine,arginine,and saccharopine,after Pst infestation.Transcriptome analysis demonstrated that differentially expressed genes(DEGs)related to secondary metabolism,including “phenolpropane and phenolics”,“terpenoids” and “flavonoids”,were strongly induced by Pst,while DEGs associated with light reaction were down-regulated.Integrated metabolomics and transcriptomics allowed us to identify significant differential metabolites that followed the same trend as the changes in their genes encoding biosynthesis.The gene regulatory network involved in response to Pst infection was constructed,which revealed that several transcription factor families including WRKYs,MYBs,and b ZIPs were identified as potentially hubs in wheat against Pst.HPLC and q RT-PCR were used to verify that HGA and its synthesis-related gene p-hydroxyphenylpyruvate dioxygenase(Ta HPD)were induced to be up-regulated by CYR23.There results suggested that HGA might play a role in wheat resistance to Pst.In conclusion,this study demonstrates the involvement of HGA in the wheat-Pst interaction process.Further research is needed to explore the potential application of HGA in developing plant disease resistance.2.Function of HGA in wheat resistance to stripe rust: In vitro inhibition tests revealed that HGA effectively suppressed the growth of pathogens such as Fusarium graminearum,Sclerotinia sclerotiorum,and Pseudomonas syringae.In the control group,where the germination rate of Pst urediospores was 60%,a concentration of 10mmol/L HGA effectively suppressed the germination of Pst urediospores,while 1mmol/L HGA resulted in abnormal germination.Exogenous HGA reduced wheat stripe rust and the accumulation of Pst biomass.Overexpression of Ta HPD in tobacco leaves using Agrobacterium-mediated transient expression technology,HGA content and resistance to S.sclerotiorum were increased.Silencing the Ta HPD gene in plants using barley streak mosaic virus(BSMV)mediated gene silencing technology resulted in hypersensitive reactions when inoculated with CYR23,and increased Pst urediospore mounds and biomass.Histological analysis showed a promotion of mycelial growth and a reduction in the accumulation of reactive oxygen species(ROS)in silenced Ta HPD plants.Further investigation using q RT-PCR and HPLC confirmed that silencing Ta HPD significantly decreased the relative expression of Ta HPD and HGA levels in infected plants.These findings indicate that HGA directly inhibits the growth of pathogens and that the content of HGA plays a crucial role in plant resistance to diseases.3.HGA involved in disease resistance signaling pathway: The wheat transcriptome was sequenced by exogenous HGA treatment,and the Map Man analysis revealed that up-regulated DEGs were mainly concentrated in “Phenylpropanoids &Phernlics” and “Nucleotides”,while down-regulated DEGs were mainly concentrated in “Light Reaction”.Further analysis showed that exogenous HGA strongly induced phenylpropanoids and lignin metabolism in wheat,with up-regulated DEGs concentrated in “Phenylpropanoids” and “Lignin and lignans”.Plant-biotic interaction panel analysis revealed an enrichment of beta glucanase,MAPK,Glutations Stransference,and Jasmonic acid(JA)pathways among up-regulated DEGs,HGA also induced up-regulated expression of plant pattern recognition receptors.indicating that HGA can induce plant defense response genes and plant hormones.To confirm these findings,transcriptomic data were subjected to q RT-PCR,the results showed that the relative expression of defense genes such as chitinase,β-glucanase and peroxidase were increased after exogenous HGA treatment.Exogenous HGA activated the JA biosynthetic pathway in plants,and JA pathway-related synthetic genes and JA content were induced to be up-regulated by HGA.And exogenous HGA could enhance the expression of lignin and ROS-related genes and increase lignin and ROS accumulation.These results suggested that HGA is involved in JA signaling-mediated biosynthesis of phenylpropanoids metabolism,enhancing wheat resistance to Pst.In conclusion,this study outlines the involvement of HGA in wheat-Pst interactions and its role in regulating resistance to wheat stripe rust.This research enhances our understanding of the molecular mechanisms underlying this interaction,and highlights the potential for HGA to be a valuable tool in the control of wheat stripe rust.By shedding light on these important aspects,our findings contribute to the theoretical basis for green control of wheat stripe rust.