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Chemical barriers contribute to nonhost resistance, which is defined as the resistance of an entire plant species to nonadapted pathogen species. However, the molecular basis of metabolic defense in nonhost resistance remains elusive. Here, we report genetic evidence for the essential role of phytoalexin capsidiol in nonhost resistance of pepper (Capsicum spp.) to potato late blight Phytophthora infestans using transcriptome and genome analyses. Two different genes for capsidiol biosynthesis, 5-epi-aristolochene synthase (EAS) and 5-epi-aristolochene-1,3-dihydroxylase (EAH), belong to multigene families. However, only a subset of EAS/EAH gene family members were highly induced upon P. infestans infection, which was associated with parallel accumulation of capsidiol in P. infestans-infected pepper. Silencing of EAS homologs in pepper resulted in a significant decrease in capsidiol accumulation and allowed the growth of nonadapted P. infestans that is highly sensitive to capsidiol. Phylogenetic and genomic analyses of EAS/EAH multigene families revealed that the emergence of pathogen-inducible EAS/EAH genes in Capsicum-specific genomic regions rendered pepper a nonhost of P. infestans. This study provides insights into evolutionary aspects of nonhost resistance based on the combination of a species-specific phytoalexin and sensitivity of nonadapted pathogens.

Background Transposable elements are major evolutionary forces which can cause new genome structure and species diversification. The role of transposable elements in the expansion of nucleotide-binding and leucine-rich-repeat proteins (NLRs), the major disease-resistance gene families, has been unexplored in plants. Results We report two high-quality de novo genomes ( Capsicum baccatum and C. chinense ) and an improved reference genome ( C. annuum ) for peppers. Dynamic genome rearrangements involving translocations among chromosomes 3, 5, and 9 were detected in comparison between C. baccatum and the two other peppers. The amplification of athila LTR-retrotransposons, members of the gypsy superfamily, led to genome expansion in C. baccatum . In-depth genome-wide comparison of genes and repeats unveiled that the copy numbers of NLRs were greatly increased by LTR-retrotransposon-mediated retroduplication. Moreover, retroduplicated NLRs are abundant across the angiosperms and, in most cases, are lineage-specific. Conclusions Our study reveals that retroduplication has played key roles for the massive emergence of NLR genes including functional disease-resistance genes in pepper plants.

This study investigates how each environmental, social, and governance (ESG) dimension relates to tax avoidance in well- and poorly governed firms. The analysis uses data from 2016 to 2020 on A-share companies listed on the Shanghai and Shenzhen stock exchanges and three panel methodologies: pooled ordinary least squares, random effects, and fixed effects models. The results show that not all ESG dimensions are equally associated with tax avoidance, and the relationship between ESG and tax avoidance differs between well- and poorly governed firms. For well-governed firms, the social and governance dimensions positively correlate with tax avoidance, whereas the environmental dimension does not. For poorly governed firms, none of the three dimensions correlate with tax avoidance. These findings suggest that ESG and tax avoidance are more compatible than conflicting. Moreover, they underscore the importance of good corporate governance in enabling tax avoidance as an ESG-compatible strategy. This study addresses the debatable relationship between ESG and tax avoidance, which has significant implications for stakeholders, including managers, investors, and policymakers. Plain Language Summary Exploring the relationship between ESG and tax strategies This study explores the relationship between environmental, social, and governance (ESG) practices and tax avoidance among A-share companies listed on the Shanghai and Shenzhen stock exchanges from 2016 to 2020. Specifically, it examines whether this relationship differs between well- and poorly governed firms. The findings reveal that the social and governance dimensions of ESG are linked to higher tax avoidance in well-governed firms, whereas the environmental dimension is not. In poorly governed firms, none of the ESG dimensions is significantly related to tax avoidance. This suggests that ESG practices can align with tax avoidance strategies, and good governance is crucial for this alignment. This study provides valuable insights for managers, investors, and policymakers on the importance of good governance in harmonizing tax strategies with ESG.

Nonhost resistance (NHR) is a plant immune response to resist most pathogens. The molecular basis of NHR is poorly understood, but recognition of pathogen effectors by immune receptors, a response known as effector‐triggered immunity, has been proposed as a component of NHR. We performed transient expression of 54 Phytophthora infestansRXLR effectors in pepper (Capsicum annuum) accessions. We used optimized heterologous expression methods and analyzed the inheritance of effector‐induced cell death in an F₂ population derived from a cross between two pepper accessions. Pepper showed a localized cell death response upon inoculation with P. infestans, suggesting that recognition of effectors may contribute to NHR in this system. Pepper accessions recognized as many as 36 effectors. Among the effectors, PexRD8 and Avrblb2 induced cell death in a broad range of pepper accessions. Segregation of effector‐induced cell death in an F₂ population derived from a cross between two pepper accessions fit 15 : 1, 9 : 7 or 3 : 1 ratios, depending on the effector. Our genetic data suggest that a single or two independent/complementary dominant genes are involved in the recognition of RXLR effectors. Multiple loci recognizing a series of effectors may underpin NHR of pepper to P. infestans and confer resistance durability.

Summary Nonhost resistance (NHR) is a robust plant immune response against non‐adapted pathogens. A number of nucleotide‐binding leucine‐rich repeat (NLR) proteins that recognize non‐adapted pathogens have been identified, although the underlying molecular mechanisms driving robustness of NHR are still unknown. Here, we screened 57 effectors of the potato late blight pathogen Phytophthora infestans in nonhost pepper (Capsicum annuum) to identify avirulence effector candidates. Selected effectors were tested against 436 genome‐wide cloned pepper NLRs, and we identified multiple functional NLRs that recognize P. infestans effectors and confer disease resistance in the Nicotiana benthamiana as a surrogate system. The identified NLRs were homologous to known NLRs derived from wild potatoes that recognize P. infestans effectors such as Avr2, Avrblb1, Avrblb2, and Avrvnt1. The identified CaRpi‐blb2 is a homologue of Rpi‐blb2, recognizes Avrblb2 family effectors, exhibits feature of lineage‐specifically evolved gene in microsynteny and phylogenetic analyses, and requires pepper‐specific NRC (NLR required for cell death)‐type helper NLR for proper function. Moreover, CaRpi‐blb2–mediated hypersensitive response and blight resistance were more tolerant to suppression by the PITG_15 278 than those mediated by Rpi‐blb2. Combined results indicate that pepper has stacked multiple NLRs recognizing effectors of non‐adapted P. infestans, and these NLRs could be more tolerant to pathogen‐mediated immune suppression than NLRs derived from the host plants. Our study suggests that NLRs derived from nonhost plants have potential as untapped resources to develop crops with durable resistance against fast‐evolving pathogens by stacking the network of nonhost NLRs into susceptible host plants.

Background Dual RNA sequencing is a powerful tool that enables a comprehensive understanding of the molecular dynamics underlying plant-microbe interactions. RNA sequencing (RNA-seq) poses technical hurdles in the transcriptional analysis of plant-bacterial interactions, especially in bacterial transcriptomics, owing to the presence of abundant ribosomal RNA (rRNA), which potentially limits the coverage of essential transcripts. Therefore, to achieve cost-effective and comprehensive sequencing of the bacterial transcriptome, it is imperative to devise efficient methods for eliminating rRNA and enhancing the proportion of bacterial mRNA. In this study, we modified a strand-specific dual RNA-seq method with the goal of enriching the proportion of bacterial mRNA in the bacteria-infected plant samples. The enriched method involved the sequential separation of plant mRNA by poly A selection and rRNA removal for bacterial mRNA enrichment followed by strand specific RNA-seq library preparation steps. We assessed the efficiency of the enriched method in comparison to the conventional method by employing various plant-bacterial interactions, including both host and non-host resistance interactions with pathogenic bacteria, as well as an interaction with a beneficial rhizosphere associated bacteria using pepper and tomato plants respectively. Results In all cases of plant-bacterial interactions examined, an increase in mapping efficiency was observed with the enriched method although it produced a lower read count. Especially in the compatible interaction with Xanthmonas campestris pv. Vesicatoria race 3 (Xcv3), the enriched method enhanced the mapping ratio of Xcv3 - infected pepper samples to its own genome (15.09%; 1.45-fold increase) and the CDS (8.92%; 1.49-fold increase). The enriched method consistently displayed a greater number of differentially expressed genes (DEGs) than the conventional RNA-seq method at all fold change threshold levels investigated, notably during the early stages of Xcv3 infection in peppers. The Gene Ontology (GO) enrichment analysis revealed that the DEGs were predominantly enriched in proteolysis, kinase, serine type endopeptidase and heme binding activities. Conclusion The enriched method demonstrated in this study will serve as a suitable alternative to the existing RNA-seq method to enrich bacterial mRNA and provide novel insights into the intricate transcriptomic alterations within the plant-bacterial interplay.

Transcription activator-like effector (TALE) proteins of the plant pathogenic bacterial genus Xanthomonas bind to and transcriptionally activate host susceptibility genes, promoting disease. Plant immune systems have taken advantage of this mechanism by evolving TALE binding sites upstream of resistance (R) genes. For example, the pepper Bs3 and rice Xa27 genes are hypersensitive reaction plant R genes that are transcriptionally activated by corresponding TALEs. Both R genes have a hallmark expression pattern in which their transcripts are detectable only in the presence and not the absence of the corresponding TALE. By transcriptome profiling using next-generation sequencing (RNA-seq), we tested whether we could avoid laborious positional cloning for the isolation of TALE-induced R genes. In a proof-of-principle experiment, RNA-seq was used to identify a candidate for Bs4C , an R gene from pepper that mediates recognition of the Xanthomonas TALE protein AvrBs4. We identified one major Bs4C candidate transcript by RNA-seq that was expressed exclusively in the presence of AvrBs4. Complementation studies confirmed that the candidate corresponds to the Bs4C gene and that an AvrBs4 binding site in the Bs4C promoter directs its transcriptional activation. Comparison of Bs4C with a nonfunctional allele that is unable to recognize AvrBs4 revealed a 2-bp polymorphism within the TALE binding site of the Bs4C promoter. Bs4C encodes a structurally unique R protein and Bs4C -like genes that are present in many solanaceous genomes seem to be as tightly regulated as pepper Bs4C . These findings demonstrate that TALE-specific R genes can be cloned from large-genome crops with a highly efficient RNA-seq approach.

Pyropia yezoensis (P. yezoensis) is an important marine algae. Its high protein content serves as a good source of biologically active peptides. Potent inhibitory effects on the production of inflammatory mediators were observed in a bioactive peptide derived from P. yezoensis (peptide from P. yezoensis; PPY1), as demonstrated in lipopolysaccha-ride (LPS)-stimulated macrophages. The present study showed that peptide concentrations ranging from 250 to 1,000 ng/ml had no significant cytotoxicity in the cell viability assay when applied to the RAW 264.7 cells for 24 h. PPY1 completely inhibited LPS-stimulated nitric oxide (NO) release in a dose-dependent manner. Fluorescence intensity, corresponding to intracellular reactive oxygen species (ROS) produced by 10 ng/ml LPS-stimulated cells, significantly shifted, indicating that the peptide reduced the level of ROS. Furthermore, PPY1 exerted potent inhibitory activity to reduce the release of pro-inflammatory cytokines (inducible NO synthase, cyclo-oxygenase-2, interleukin-1β and tumor necrosis factor-α) in LPS-stimulated macrophages in a dose-dependent manner. These results also showed that the anti-inflammatory activity of PPY1 was associated with downregulation of extracellular signal-regulated kinase, protein 38, and c-jun NH2-terminal kinase phosphorylation in the mitogen-activated protein kinase pathways. In conclusion, PPY1 can have a significant role as an anti-inflammatory agent, with a potential for use in marine products.

Context: 2,7″-Phloroglucinol-6,6′-bieckol is a type of phlorotannin isolated from brown algae, Ecklonia cava Kjellman (Phaeophyceae; Laminareaceae). 2,7″-Phloroglucinol-6,6′-bieckol mediates antioxidant activities. However, there has been no research on improving postprandial hyperglycaemia using 2,7″-phloroglucinol-6,6′-bieckol.Objective: This study investigated the inhibitory effects of 2,7″-phloroglucinol-6,6′-bieckol on activities of α-glucosidase and α-amylase as well as its alleviating effect on postprandial hyperglycaemia in streptozotocin-induced diabetic mice.Materials and methods: α-Glucosidase and α-amylase inhibitory assays were carried out. The effect of 2,7″-phloroglucinol-6,6′-bieckol on hyperglycaemia after a meal was measured by postprandial blood glucose in streptozotocin-induced diabetic and normal mice. The mice were treated orally with soluble starch (2 g/kg BW) alone (control) or with 2,7″-phloroglucinol-6,6′-bieckol (10 mg/kg bw) or acarbose (10 mg/kg BW) dissolved in 0.2 mL water. Blood samples were taken from tail veins at 0, 30, 60, and 120 min and blood glucose was measured by a glucometer.Results: 2,7″-Phloroglucinol-6,6′-bieckol showed higher inhibitory activities than acarbose, a positive control against α-glucosidase and α-amylase. The IC50 values of 2,7″-phloroglucinol-6,6′-bieckol against α-glucosidase and α-amylase were 23.35 and 6.94 μM, respectively, which was found more effective than observed with acarbose (α-glucosidase IC50 of 130.04 μM; α-amylase IC50 of 165.12 μM). In normal mice, 2,7″-phloroglucinol-6,6′-bieckol significantly suppressed the postprandial hyperglycaemia caused by starch. The 2,7″-phloroglucinol-6,6′-bieckol administration group (2349.3 mmol·min/L) had a lower area under the curve (AUC) glucose response than the control group (2690.83 mmol·min/L) in diabetic mice.Discussion and conclusion: 2,7″-Phloroglucinol-6,6′-bieckol might be used as an inhibitor of α-glucosidase and α-amylase as well as to delay absorption of dietary carbohydrates.

Purpose This paper aims to verify the effect of corporate social responsibility (CSR) on Chinese listed firms’ earnings management and tax avoidance. Specifically, this study investigates whether government-guided CSR implementation indeed drives firms to behave in a responsible manner by constraining earnings management and tax avoidance. Design/methodology/approach The paper analyses a sample of Chinese listed companies that are confronted with the unique situation of CSR being developed at a rapid pace by government-led policy and regulation. The study further investigates whether the effect of CSR on earnings management and tax avoidance is different for state-owned and private enterprises by partitioning the sample into these two subgroups. Findings The findings of this study show that government-guided CSR could be effective in reducing the firms’ earnings management and tax avoidance, even though the effect is limited to state-owned enterprises. Originality/value This paper provides new evidence on the relation of CSR with earnings management and tax avoidance in the Chinese context and sheds light on the importance of differentiating between the state-owned and private enterprises when studying the corporate behaviors of Chinese firms.