Screening of hulless barley germplasm resources for resistance to Pyrenophora graminea and Morphological observation and transcriptomic analysis following infection

In order to preliminarily explore the response mechanism of highland barley germplasm resources after being infected by leaf stripe disease at the molecular level, and to provide relevant candidate genes for the subsequent research on disease-resistant genes. In this study, 28 highland barley germplasm resources were identified for indoor disease resistance using the highly pathogenic strains L-7 and FS-18, and the disease-resistant resource (ZYM2179) and the disease-susceptible resource (Chaiqing No.1) were selected; then the Pyrenophora graminea L-7 was used to infect the disease-resistant resource (ZYM2179) and the disease-susceptible resource (Chaiqing No.1), and WGA-AF488 slice production and RNA-seq sequencing were performed at different time periods.The results showed that the degree of invasion of the stripe pathogen increased with the lengthening of the infection time in the same highland barley germplasm resource, and the number of hyphal invasions also increased, and the degree of invasion of different highland barley germplasm resources infected at the same time was also different. At the same time, it was found that the incidence rate of the disease-susceptible resource also increased with the increase of the infection time; a total of 18,523 differentially expressed genes were identified by comparing the transcriptome sequencing data at different time points after the Pyrenophora graminea infection; when the stripe pathogen infected the highland barley germplasm resources at different time periods, the number of differentially expressed genes enriched in the GO and KEGG pathways between the disease-resistant and disease-susceptible resources was significantly different; a total of 104 differentially expressed genes related to the Pyrenophora graminea infection were obtained in the disease-resistant resource, and the main enriched pathways included metabolic pathways, biosynthesis of other secondary metabolites, carbon sequestration in photosynthetic organisms, plant-pathogen interactions, nitrogen metabolism, microbial metabolism in different environments, carbon metabolism, etc. To verify the accuracy of the RNA-seq data, Randomly select 10 genes related to leaf stripe disease resistance pathways (HSP70-4, PER1, SCE1, NAR-7, HSP26.2, IBI1, TPI, At3g47520, AL-AAT2, STE1) from 104 candidate disease resistance genes.The expression levels of the differentially expressed genes before and after the leaf stripe disease infection were statistically analyzed by qRT-PCR, and the results showed that the fluorescence quantification of these 10 anti-leaf stripe disease genes was basically consistent with the transcriptome sequencing results.This study aims to investigate the differences in barley under Pyrenophora graminea fungus stress through disease resistance identification, morphological observation, and transcriptome sequencing, in order to provide a theoretical basis for the discovery of barley leaf stripe disease resistant genes and the study of leaf stripe disease resistance mechanisms. This is of great significance for the cultivation of new barley varieties resistant to leaf stripe disease and the development of the barley industry.