Ralstonia solanacearum Type III Effector RipJ Triggers Bacterial Wilt Resistance in Solanum pimpinellifolium.

Ralstonia solanacearum causes bacterial wilt disease in solanaceous crops. Identification of avirulence type III-secreted effectors recognized by specific disease resistance proteins in host plant species is an important step toward developing durable resistance in crops. In the present study, we show that R. solanacearum effector RipJ functions as an avirulence determinant in Solanum pimpinellifolium LA2093. In all, 10 candidate avirulence effectors were shortlisted based on the effector repertoire comparison between avirulent Pe_9 and virulent Pe_1 strains. Infection assays with transgenic strain Pe_1 individually carrying a candidate avirulence effector from Pe_9 revealed that only RipJ elicits strong bacterial wilt resistance in S. pimpinellifolium LA2093. Furthermore, we identified that several RipJ natural variants do not induce bacterial wilt resistance in S. pimpinellifolium LA2093. RipJ belongs to the YopJ family of acetyltransferases. Our sequence analysis indicated the presence of partially conserved putative catalytic residues. Interestingly, the conserved amino acid residues in the acetyltransferase catalytic triad are not required for effector-triggered immunity. In addition, we show that RipJ does not autoacetylate its lysine residues. Our study reports the identification of the first R. solanacearum avirulence protein that triggers bacterial wilt resistance in tomato. We expect that our discovery of RipJ as an avirulence protein will accelerate the development of bacterial wilt-resistant tomato varieties in the future.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Do longer root hairs improve phosphorus uptake? Testing the hypothesis with transgenic Brachypodium distachyon lines overexpressing endogenous RSL genes.

Mutants without root hairs show reduced inorganic orthophosphate (Pi) uptake and compromised growth on soils when Pi availability is restricted. What is less clear is whether root hairs that are longer than wild-type provide an additional benefit to phosphorus (P) nutrition. This was tested using transgenic Brachypodium lines with longer root hairs. The lines were transformed with the endogenous BdRSL2 and BdRSL3 genes using either a constitutive promoter or a root hair-specific promoter. Plants were grown for 32 d in soil amended with various Pi concentrations. Plant biomass and P uptake were measured and genotypes were compared on the basis of critical Pi values and P uptake per unit root length. Ectopic expression of RSL2 and RSL3 increased root hair length three-fold but decreased plant biomass. Constitutive expression of BdRSL2, but not expression of BdRSL3, consistently improved P nutrition as measured by lowering the critical Pi values and increasing Pi uptake per unit root length. Increasing root hair length through breeding or biotechnology can improve P uptake efficiency if the pleotropic effects on plant biomass are avoided. Long root hairs, alone, appear to be insufficient to improve Pi uptake and need to be combined with other traits to benefit P nutrition.

Genome-wide transcriptome analysis of expression in rice seedling roots in response to supplemental nitrogen.

Nitrogen (N) is the most important macronutrient for plant growth and grain yields. For rice crops, nitrate and ammonium are the major N sources. To explore the genomic responses to ammonium supplements in rice roots, we used 17-day-old seedlings grown in the absence of external N that were then exposed to 0.5mM (NH4)2SO4 for 3h. Transcriptomic profiles were examined by microarray experiments. In all, 634 genes were up-regulated at least two-fold by the N-supplement when compared with expression in roots from untreated control plants. Gene Ontology (GO) enrichment analysis revealed that those upregulated genes are associated with 23 GO terms. Among them, metabolic processes for diverse amino acids (i.e., aspartate, threonine, tryptophan, glutamine, l-phenylalanine, and thiamin) as well as nitrogen compounds are highly over-represented, demonstrating that our selected genes are suitable for studying the N-response in roots. This enrichment analysis also indicated that nitrogen is closely linked to diverse transporter activities by primary metabolites, including proteins (amino acids), lipids, and carbohydrates, and is associated with carbohydrate catabolism and cell wall organization. Integration of results from omics analysis of metabolic pathways and transcriptome data using the MapMan tool suggested that the TCA cycle and pathway for mitochondrial electron transport are co-regulated when rice roots are exposed to ammonium. We also investigated the expression of N-responsive marker genes by performing a comparative analysis with root samples from plants grown under different NH4(+) treatments. The diverse responses to such treatment provide useful insight into the global changes related to the shift from an N-deficiency to an enhanced N-supply in rice, a model crop plant.

Dietary magnesium intake and metabolic syndrome in the adult population: dose-response meta-analysis and meta-regression.

ncreasing evidence has suggested an association between dietary magnesium intake and metabolic syndrome. However, previous research examining dietary magnesium intake and metabolic syndrome has produced mixed results. Our objective was to determine the relationship between dietary magnesium intake and metabolic syndrome in the adult population using a dose-response meta-analysis. We searched the PubMed, Embase and the Cochrane Library databases from August, 1965, to May, 2014. Observational studies reporting risk ratios with 95% confidence intervals (CIs) for metabolic syndrome in ≥ 3 categories of dietary magnesium intake levels were selected. The data extraction was performed independently by two authors, and the quality of the studies was evaluated using the Risk of Bias Assessment Tool for Nonrandomized Studies (RoBANS). Based on eight cross-sectional studies and two prospective cohort studies, the pooled relative risks of metabolic syndrome per 150 mg/day increment in magnesium intake was 0.88 (95% CI, 0.84-0.93; I(2) = 36.3%). The meta-regression model showed a generally linear, inverse relationship between magnesium intake (mg/day) and metabolic syndrome. This dose-response meta-analysis indicates that dietary magnesium intake is significantly and inversely associated with the risk of metabolic syndrome. However, randomized clinical trials will be necessary to address the issue of causality and to determine whether magnesium supplementation is effective for the prevention of metabolic syndrome.

Impact of rosiglitazone therapy on the lipid profile, glycemic control, and medication costs among type 2 diabetes patients.

OBJECTIVE: To investigate the impact of rosiglitazone therapy on lipid profiles, glycemic control, and costs associated with cholesterol-lowering and diabetic medications among Type 2 diabetes mellitus (T2DM) patients in a standard practice setting. METHOD: This retrospective cohort study was conducted using data from the General Practice Research Database during 1999-2006. T2DM patients were classified based on the addition of rosiglitazone versus either metformin or a sulfonylurea ('comparison group') to pre-existing glucose lowering agents. After propensity score matching to control for differences in baseline patient characteristics, 1450 matched pairs were identified. The mean changes in total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), glycosylated hemoglobin A1C (A1C), and daily medication costs were calculated. To investigate the incremental costs for lipid-lowering medications, a two-part model was utilized. RESULTS: The mean changes in TC and A1C for the rosiglitazone and metformin/sulfonylurea groups were 9 vs -10 mg/dL for TC, -2 vs -9 mg/dL for LDL-C, and -0.8% vs. -1.2% for A1C, respectively. The mean changes in daily medication costs of glucose- and lipid-lowering drugs were $3.95 for rosiglitazone patients and $0.27 for metformin/sulfonylurea patients. For patients with positive incremental lipid-lowering costs, rosiglitazone use was significantly associated with costs eight times greater than metformin/sulfonylureas. Generalizability of the study is limited due to cost estimates using the national formulary and potential selection bias. CONCLUSIONS: Addition of rosiglitazone to an existing antidiabetic medication regimen improved glycemic control to a lesser extent than metformin/sulfonylurea, and also deteriorated patients' lipid profiles, leading to significantly greater daily costs. Economic evaluations of alternative therapies should consider such costs to estimate the full impact of different therapeutic approaches in diabetes.

To compare the efficacy and safety of nifedipine sustained release with Ginkgo biloba extract to treat patients with primary Raynaud's phenomenon in South Korea; Korean Raynaud study (KOARA study).

This study examined the efficacy and safety of nifedipine sustained release (nifedipine SR) compared with Ginkgo biloba extract as treatment for primary Raynaud's phenomenon (RP) in Korea. Primary RP were screened and assigned to either the nifedipine SR group (Group N) or the Ginkgo biloba extract group (Group G) in the ratio of 2:1. After a run-in period of 2 weeks, patients received treatment for 8 weeks. We observed the percent improvement of the RP attack rate between before and after the 8-week treatment. Ninety-three subjects were randomly assigned. The percent improvement in Group N was 50.1% at 8 weeks after treatment, while it was 31.0% in Group G (p = 0.03). No serious adverse events occurred, and almost adverse events were mild and improved without specific treatment. nifedipine SR was more effective than Ginkgo biloba extract for treatment of primary RP in Korean patients. Both drugs were tolerable with primary RP patients.

Inhibitory effects of Stewartia koreana on osteoclast differentiation and bone resorption.

Osteoclasts are responsible for bone lysis in several bone diseases such as osteoporosis and rheumatoid arthritis. Natural products from plants have been invaluable source in discovery of compounds for new therapies. In this study, we screened plant products for potential application to therapy for bone loss using a primary osteoclastogenesis culture system and found that extract of Stewartia koreana (SKE) had a strong inhibitory effect on osteoclast formation. To gain molecular insights, we examined the effect of SKE on signaling pathways and transcription factors stimulated by the osteoclast differentiation factor RANKL. SKE suppressed the induction of c-Fos and NFATc1 by RANKL. However, SKE did not inhibit NF-kappaB activation by RANKL. Among the MAPKs stimulated by RANKL, SKE significantly reduced the activation of ERK and p38. Therefore, the anti-osteoclastogenic effect of SKE is likely to be elicited by interference with RANKL signaling to ERK and p38, which mediate the induction of c-Fos and subsequently that of NFATc1. Consistent with the in vitro effect on osteoclast differentiation, SKE showed a great inhibitory effect on in vivo bone loss in LPS-challenged mice. Taken together, we demonstrated that SKE has inhibitory effects on osteoclast differentiation in vitro and confirmed its in vivo efficacy in prevention of inflammatory bone loss.