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Abstract Background Developing wheat cultivars with durable resistance to powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is crucial for sustainable agriculture. The wheat genotype MYC exhibited high resistance to the Bgt isolate E09 at the seedling stage. Genetic analysis identified a recessive gene, temporarily named PmMYC, responsible for this resistance. Understanding the molecular mechanisms underlying this resistance is essential for advancing breeding programs. Results Bulked Segregant RNA-Seq revealed numerous alternative splicing events generated following Bgt infection, suggesting powdery mildew may disrupt alternative splicing and affect immune responses. Gene Ontology (GO) analysis indicated significant enrichment of differentially expressed genes in “response to stimuli” and “immune system processes”, implying their roles in disease defense. BSR-Seq analysis identified two high-confidence candidate regions for PmMYC on chromosome 2B, spanning 40,451,950 − 102,426,703 bp and 421,707,046–449,840,516 bp. Within these intervals, 740 genes were identified, with nonsynonymous mutations in 46 genes in the parents and bulks. Real-time PCR showed distinct expression profiles in four genes in resistant MYC compared to susceptible Yannong 21. KEGG and COG analyses of differentially expressed genes in candidate intervals revealed enrichment in immune processes related to plant-pathogen interactions, confirming that PmMYC initiated a broad immune response to prevent Bgt invasion. Conclusion The study identified key genetic intervals and genes involved in the resistance of wheat genotype MYC to Bgt. The identified genes, particularly those with altered expression profiles, could serve as valuable targets for breeding programs aimed at developing wheat cultivars with durable resistance to powdery mildew. These findings enhanced our understanding of plant-pathogen interactions and provided a foundation for future genetic and functional studies.

Abstract Background Diabetic retinopathy (DR), the principal cause of acquired blindness among the working-age population, is the most frequent microvascular complication of diabetes. Although metabolic disorders are hypothesized to play a role in its pathogenesis, the underlying mechanism remains largely elusive. Methods To elucidate the mechanism, we initially compared metabolite profiles of vitreous fluid between 23 patients with DR and 12 non-diabetic controls using liquid chromatography/tandem mass spectrometry, identifying the distinct metabolite indoxyl sulfate (IS). Subsequently, streptozotocin (STZ)-induced diabetic and IS-injected rat models were established to examine the effects of IS on retinal microvasculature. RNA sequencing was conducted to identify potential regulatory mechanisms in IS-treated human retinal endothelial cells (HREC). Finally, target gene knockdown in HREC and treatment of IS-injected rats with inhibitors (targeting IS production or downstream regulators) were employed to elucidate the detailed mechanisms and identify therapeutic targets for DR. Results Metabolomics identified 172 significantly altered metabolites in the vitreous humor of diabetics, including the dysregulated tryptophan metabolite indoxyl sulfate (IS). IS was observed to breach the blood-retinal barrier and accumulate in the intraocular fluid of diabetic rats. Both in vivo and in vitro experiments indicated that elevated levels of IS induced endothelial apoptosis and disrupted cell junctions. RNA sequencing pinpointed prostaglandin E2 (PGE2) synthetase-cyclooxygenase 2 (COX-2) as a potential target of IS. Validation experiments demonstrated that IS enhanced COX-2 expression, which subsequently increased PGE2 secretion by promoting transcription factor EGR1 binding to COX-2 DNA following entry into cells via organic anion transporting polypeptides (OATP2B1). Furthermore, inhibition of COX-2 in vivo or silencing EGR1/OATP2B1 in HREC mitigated IS-induced microcapillary damage and the activation of COX-2/PGE2. Conclusion Our study demonstrated that indoxyl sulfate (IS), a uremic toxin originating from the gut microbiota product indole, increased significantly and contributed to retinal microvascular damage in diabetic retinopathy (DR). Mechanistically, IS impaired retinal microvascular integrity by inducing the expression of COX-2 and the production of PGE2. Consequently, targeting the gut microbiota or the PGE2 pathway may offer effective therapeutic strategies for the treatment of DR. Graphical Abstract