Fatty acids (FAs) have been implicated in signaling roles in plant defense responses. We previously reported that mutation or RNAi-knockdown (OsSSI2-kd) of the rice OsSSI2 gene, encoding a stearoyl acyl carrier protein FA desaturase (SACPD), remarkably enhanced resistance to blast fungus Magnaporthe oryzae and the leaf-blight bacterium Xanthomonas oryzae pv. oryzae (Xoo). Transcriptomic analysis identified six AAA-ATPase family genes (hereafter OsAAA-ATPase1–6) upregulated in the OsSSI2-kd plants, in addition to other well-known defense-related genes. Here, we report the functional analysis of OsAAA-ATPase1 in rice’s defense response to M. oryzae. Recombinant OsAAA-ATPase1 synthesized in Escherichia coli showed ATPase activity. OsAAA-ATPase1 transcription was induced by exogenous treatment with a functional analogue of salicylic acid (SA), benzothiadiazole (BTH), but not by other plant hormones tested. The transcription of OsAAA-ATPase1 was also highly induced in response to M. oryzae infection in an SA-dependent manner, as gene induction was significantly attenuated in a transgenic rice line expressing a bacterial gene (nahG) encoding salicylate hydroxylase. Overexpression of OsAAA-ATPase1 significantly enhanced pathogenesis-related gene expression and the resistance to M. oryzae; conversely, RNAi-mediated suppression of this gene compromised this resistance. These results suggest that OsAAA-APTase1 plays an important role in SA-mediated defense responses against blast fungus M. oryzae.

Rice blast resistance (R) genes-mediated resistance response depends on various resistance-related genes involved in incompatible interactions. In this work, the expression profiles of innate rice immunity related genes were examined in the mediated resistance response of true/field resistance genes. Three sets of rice near-isogenic lines (NILs) were used: the resistant NILs carrying true resistance genes in the genetic background of the susceptible cultivar Nipponbare (NB), NB-Pib, NB-Pizt, NB-Pik and NB-Pita2; NILs bearing field resistance genes pi21 in the susceptible cultivar Aichiasahi (AA) AA-pi21, Kahei (KHR). The marker gene OsWRKY45 of salicylic acid (SA) signalling was upregulated in all tested cultivars. And, JAmyb (marker gene of jasmonic acid signalling) showed higher upregulation in the resistance lines with nucleotide-binding sites and leucine-rich repeat (NBS-LRR) R genes Pib, Pizt, Pik, Pita2 and Pikahei than in NB and KHS. SalT of abscisic acid (ABA) signalling may be involved in the R/Avr interaction, including Pizt, Pik, pi21 and Pikahei. However, SalT was shown to negatively regulate Pib/AvrPib interaction. OsPR1b and PBZ1 were differentially expressed and strongly activated at a later stage by 48 h post-inoculation. Interestingly, there was evidence that OsPR1b and PBZ1 played an important role in the pi21-mediated response. It was shown that OsRAR1 could be upregulated in the true resistance line NB-Pita2 and the field resistance line KHR, while OsSGT1 and OsHSP90 could be upregulated in all tested lines. The involvement of these genes illustrated the complexity of the downstream signalling pathways in the mediated resistance response of true/field resistance genes.

The main aim of the work is to study the regulation of gene expression in the interaction between rice and Magnaporthe oryzae by gene chip technology. In this study, we mainly focused on changes of gene expression at 24, 48, and 72 hours post-inoculation (hpi), through which we could conduct a more comprehensive analysis of rice blast-related genes in the process of infection. The results showed that the experimental groups contained 460, 1227, and 3937 significant differentially expressed genes at 24, 48, and 72 hpi, respectively. Furthermore, 115 significantly differentially expressed genes were identified in response to rice blast infection at all three time points. By annotating these 115 genes, they were divided into three categories: metabolic pathways, proteins or enzymes, and organelle components. As expected, many of these genes were known rice blast-related genes; however, we discovered new genes with high fold changes. Most of them encoded conserved hypothetical proteins, and some were hypothetically conserved genes. Our study may contribute to finding new resistance genes and understanding the mechanism of rice blast development. GRAPHICAL ABSTRACT

Plant basic leucine zipper (bZIP) proteins play an essential role in the genes expression and regulation in higher plants. They have been shown to regulate diverse plant specific phenomena, including germination, floral induction and development, seed maturation, photomorphogenesis, biotic and abiotic stresses. Resistance response mediated by the rice blast resistance gene Pi36 is a typical signal transduction, in which 12 OsbZIP genes were differentially expressed by microarray analyses. To understand the potential function of OsbZIP genes during the defense responses against rice blast, the expression analysis of these OsbZIP genes, in response to the blast fungus inoculation and the related defense signal molecules induction, were further conducted using real-time fluorescent quantitative polymerase chain reaction (PCR) technique. Our data indicates that among the 12 OsbZIP genes, the expression level eight tested genes were differentially regulated and maintained to 96 h points post inoculation in rice resistant and susceptible cultivars during Magnaporthe oryzae infection, and all of them were also significantly up-regulated by one or several kinds of exogenous plant hormones stresses. Although, these genes were induced only at early time points (1 to 24 h); it is evident that the OsbZIP genes may be involved in different signaling pathway, and play potential important functions in the defense response to rice blast. Key words: OsbZIP transcription factors, rice blast, resistance response, plant hormones stresses.

Sacred lotus (Nelumbo nucifera) is an important aquatic crop whose growth and productivity are severely constrained by environmental stresses. Salicylic Acid (SA), Jasmonic Acid (JA), and Abscisic Acid (ABA) are key plant growth regulators (PGRs) involved in stress responses, but their regulatory mechanisms in lotus remain unclear. In this study, transcriptome sequencing was performed in lotus seedlings treated with exogenous SA, JA, and ABA to characterize hormone-responsive regulatory networks. SA predominantly resulted in transcriptional repression, with responsive genes mainly associated with photosynthesis and ribosome-related pathways, whereas JA and ABA showed similar regulatory patterns with enrichment of hormone signaling and Mitogen-activated protein kinase (MAPK) pathways, but distinct roles in defense regulation and stress adaptation. A total of 607 genes were identified as commonly responsive to the three PGRs and were significantly enriched in cold response, defense response, secondary metabolism, and photosynthesis-related pathways. Protein–protein interaction analysis identified two hub genes encoding light-harvesting chlorophyll a/b-binding proteins, suggesting that the photosynthesis–antenna proteins pathway may represent a convergent regulatory node in hormone-mediated stress responses. This study provides new insights into SA-, JA-, and ABA-mediated stress responses and identifies potential candidate genes for improving stress tolerance in lotus.

Sponge gourd ( L. cylindrica Mill.), a crucial dual-purpose crop in the Cucurbitaceae family, faces severe yield losses due to diseases like Fusarium wilt and Tomato leaf curl New Delhi virus (ToLCNDV) infection. The NBS-LRR (Nucleotide-Binding Site–Leucine-Rich Repeat) gene family, core components of plant Effector-Triggered Immunity (ETI), plays a vital role in pathogen defense. This study conducted a comprehensive genome-wide analysis of the NBS-LRR gene family in Luffa cylindrica using bioinformatics tools and transcriptome data. A total of 89 NBS-LRR genes were identified and classified into seven subfamilies: TIR(Toll/Interleukin-1 Receptor)-NBS-LRR(TNL) (15), TIR-NBS(TN)(16), CC (Coiled-Coil))-NBS-LRR(CNL)(8), CC-NBS (CN) (14), NBS(N)(23), NBS-LRR (NL) (10), and RN(RPW8-NBS) (3). These genes showed irregular distribution across 12 chromosomes, with the highest density on Chr08. Phylogenetic analysis revealed five primary clades, reflecting evolutionary relationships among subfamilies. Conserved domain and motif analysis indicated intra-subfamily conservation and inter-subfamily divergence, with all members containing the core NB-ARC domain. Promoter cis -acting element analysis identified 65 elements, with light-responsive and hormone/defense-stress-responsive elements being predominant, suggesting involvement in multiple biological processes. Intra-species synteny analysis found two homologous gene pairs between Chr02 and Chr06, while inter-species analysis showed closer evolutionary ties with cucumber (18 orthologous pairs) than Arabidopsis (1 ortholog) and no orthologs with rice. Tissue-specific expression analysis revealed highest expression in roots, and disease response analysis identified six genes associated with ToLCNDV resistance and nine genes linked to Fusarium wilt resistance. These findings provide valuable resources for understanding the molecular basis of disease resistance in L. cylindrica and accelerating disease-resistant breeding.