The bacterial pathogen Ralstonia solanacearum causes wilt disease on Arabidopsis thaliana and tomato (Solanum lycopersicum). This pathogen uses type III effectors to inhibit the plant immune system; however, how individual effectors interfere with plant immune responses, including transcriptional reprograming, remain elusive. Here, we show that the type III effector RipAB targets Arabidopsis TGACG SEQUENCE-SPECIFIC BINDING PROTEIN (TGA) transcription factors, the central regulators of plant immune gene regulation, via physical interaction in the nucleus to dampen immune responses. RipAB was required for R. solanacearum virulence on wild-type tomato and Arabidopsis but not Arabidopsis tga1 tga4 and tga2 tga5 tga6 mutants. Stable expression of RipAB in Arabidopsis suppressed the pathogen-associated molecular pattern-triggered reactive oxygen species (ROS) burst and immune gene induction as well as salicylic acid (SA) regulons including RBOHD and RBOHF, responsible for ROS production, all of which were phenocopied by the tga1 tga4 and tga2 tga5 tga6 mutants. We found that TGAs directly activate RBOHD and RBOHF expression and that RipAB inhibits this through interfering with the recruitment of RNA polymerase II. These results suggest that TGAs are the bona fide and major virulence targets of RipAB, which disrupts SA signaling by inhibiting TGA activity to achieve successful infection.

Purpose: To evaluate the therapeutic effect of Epimedium brevicornum Maxim. extract (EBME) on ovariectomy-induced osteoporosis in rats. Methods: The rats were divided into six experimental groups, viz, control (group 1) and five ovariectomy-induced (OVX) groups. The OVX groups include OVX-inducing agent only group (group 2), OVX with 17ß-estradiol (E₂, 25 μg/kg/day, group 3), OVX with 60 mg EBME/kg body weight/day (group 4), OVX with 120 mg EBME/kg body weight/day (group 5) and OVX with 240 mg EBME/kg body weight/day (group 6). The treatment started for the OVX groups with a single weekly dose of OVX inducing agent for 4 weeks, followed by oral daily dose of E₂ (group 3) or EBME (groups 4, 5 and 6) for another 16 weeks. Bone mineral density (BMD) of the 4th lumber vertebrae (4LV) and right femur of each rat was estimated. BMD determination was preceded by the measurement of the length of the femur and identification of diaphysis (center). Trabecular microarchitecture was assessed via three representative 4LV. The other parameters measured in this study were serum alkaline phosphatase (ALP), urinary calcium (U-Ca), urinary phosphorus (U-P), urinary creatinine (U-SCr) and osteocalcin (OC) levels. Result: The results showed that the BMD decrease induced by OVX in 4LV and femur was significantly mitigated by high dose of EBME. EBME also protected the trabecular microarchitecture against OVXassociated deterioration, evidenced by decreased bone turnover marker levels in 4LV at high EBME dose. Trabecular number (Tb-N, 3.7 ± 0.2), trabecular thickness (Tb-Th, 0.082 ± 0.011), and trabecular spacing (Tb-Sp, 0.17 ± 0.01) of the highest dose EBME-treated OVX rats ’4LV were significantly (p < 0.05) different from the corresponding values of EBME-free OVX rats. Conclusion: The results reveal that administration of high doses of EBME lasting for 16 weeks not only protected against OVX-induced osteoporosis in rats but was also without the risk of endometrial hyperplasia. Thus, the extract may be a better alternative to other agents in current use for the treatment of postmenopausal osteoporosis in elderly women. However, its efficacy and safety require further investigations. Keywords: Epimedium brevicornum Maxim., Postmenopausal osteoporosis, Ovariectomy, Bone mineral density

Background: The Trihelix transcription factor family, characterized by a unique triple-helix structure, plays important roles in plant growth, development, and responses to biotic stresses. Cucumber ( Cucumis sativus L.), a globally important horticultural crop, suffers significant growth and yield losses under biotic stresses (e.g., pathogens, insects, nematodes). Although Trihelix transcription factors have been well characterized in model plants like Arabidopsis thaliana , systematic analyses in cucumber are still limited. This study aims to comprehensively identify the Trihelix transcription factor gene family in cucumber using bioinformatics methods and analyze their expression patterns under biotic stresses, thereby providing insights into their potential roles in cucumber growth, development, and stress responses. Results: Using Arabidopsis Trihelix sequences as queries, we identified 29 CsaTri genes in Cucumis sativus L. cv. Chinese Long v4.0 genome (all containing the canonical Trihelix domain, named CsaTri1 – CsaTri29 by chromosomal position). Phylogenetic analysis classified these genes into 5 subfamilies (GT-1, GT-2, SH4, GT-γ, and SIP1), and they are unevenly distributed across 7 chromosomes. Gene structure and functional motif analyses revealed highly conserved motifs and domain architectures within the same subfamily. Cis-regulatory element analysis indicated that these genes may be involved in hormone responses, stress responses, and growth and development processes. Tissue expression analysis showed that CsaTri12/CsaTri27/CsaTri28/CsaTri29 are highly expressed in stems, while CsaTri8/CsaTri21 are highly expressed in roots. Transcriptome data and qRT-PCR results indicated that CsaTri genes actively respond to pathogen stress. Co-expression analysis linked CsaTri genes to immune pathways (PAMP recognition via LRR-RLK, post-transcriptional regulation via RNA metabolism/ubiquitin-proteasome system). Conclusions: Our study provides the first systematic characterization of the Cucumis sativus L. Trihelix transcription factor family, encompassing genomic, structural, evolutionary, and expression features. The identification of stress-responsive genes (e.g., CsaTri18 , SIP1 subfamily) and their associated regulatory networks provides valuable insights into the potential biotic stress defense mechanisms of Cucumis sativus L. These findings lay a foundation for future functional validation of key CsaTri genes and offer potential candidate targets for breeding stress-resistant cucumber varieties.

The genus Blunervirus comprises plant viruses that infect a diverse range of plants, but no blunervirus has been reported infecting elm trees (Ulmus parvifolia) in China to date. Using high-throughput sequencing and reverse-transcription PCR assays, a novel blunervirus, tentatively named elm blunervirus 1 (ElmBlV1), was identified from a symptomatic elm plant (Ulmus parvifolia) in China. The genome of ElmBlV1 harbors canonical molecular features of blunerviruses and comprises six RNA segments (RNAs1–6), with RNA5 and 6 being two additional genomic components not reported in known blunerviruses. Sequence analyses revealed amino acid (aa) identity of ElmBlV1 proteins ranging from 25.9% (polyprotein encoded by RNA1) to 64.2% (movement protein encoded by RNA4) relative to reported blunerviruses and include five orphan open reading frames. Phylogenetically, ElmBlV1 is most closely related to blueberry necrotic ring blotch virus. Furthermore, ElmBlV1 P37 localizes to both plasmodesmata and the nucleus. Additionally, the RNA reads mapping revealed high read coverage was observed on RNAs3–4 for this virus. To our knowledge, this is the first report of a blunervirus infecting an elm tree in China. Our results enrich the diversity of known viruses in the genus of Blunervirus and expand our understanding of their genomic characteristics and molecular biology.