Recognition of Microbe- and Damage-Associated Molecular Patterns by Leucine-Rich Repeat Pattern Recognition Receptor Kinases Confers Salt Tolerance in Plants.

In plants, a first layer of inducible immunity is conferred by pattern recognition receptors (PRRs) that bind microbe- and damage-associated molecular patterns to activate pattern-triggered immunity (PTI). PTI is strengthened or followed by another potent form of immunity when intracellular receptors recognize pathogen effectors, termed effector-triggered immunity. Immunity signaling regulators have been reported to influence abiotic stress responses as well, yet the governing principles and mechanisms remain ambiguous. Here, we report that PRRs of a leucine-rich repeat ectodomain also confer salt tolerance in Arabidopsis thaliana, following recognition of cognate ligands such as bacterial flagellin (flg22 epitope) and elongation factor Tu (elf18 epitope), and the endogenous Pep peptides. Pattern-triggered salt tolerance (PTST) requires authentic PTI signaling components; namely, the PRR-associated kinases BAK1 and BIK1 and the NADPH oxidase RBOHD. Exposure to salt stress induces the release of Pep precursors, pointing to the involvement of the endogenous immunogenic peptides in developing plant tolerance to high salinity. Transcriptome profiling reveals an inventory of PTST target genes, which increase or acquire salt responsiveness following a preexposure to immunogenic patterns. In good accordance, plants challenged with nonpathogenic bacteria also acquired salt tolerance in a manner dependent on PRRs. Our findings provide insight into signaling plasticity underlying biotic or abiotic stress cross-tolerance in plants conferred by PRRs.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Danger peptide receptor signaling in plants ensures basal immunity upon pathogen-induced depletion of BAK1.

Pathogens infect a host by suppressing defense responses induced upon recognition of microbe-associated molecular patterns (MAMPs). Despite this suppression, MAMP receptors mediate basal resistance to limit host susceptibility, via a process that is poorly understood. The Arabidopsis leucine-rich repeat (LRR) receptor kinase BAK1 associates and functions with different cell surface LRR receptors for a wide range of ligands, including MAMPs. We report that BAK1 depletion is linked to defense activation through the endogenous PROPEP peptides (Pep epitopes) and their LRR receptor kinases PEPR1/PEPR2, despite critical defects in MAMP signaling. In bak1-knockout plants, PEPR elicitation results in extensive cell death and the prioritization of salicylate-based defenses over jasmonate-based defenses, in addition to elevated proligand and receptor accumulation. BAK1 disruption stimulates the release of PROPEP3, produced in response to Pep application and during pathogen challenge, and renders PEPRs necessary for basal resistance. These findings are biologically relevant, since specific BAK1 depletion coincides with PEPR-dependent resistance to the fungal pathogen Colletotrichum higginsianum. Thus, the PEPR pathway ensures basal resistance when MAMP-triggered defenses are compromised by BAK1 depletion.

The NB-LRR proteins RGA4 and RGA5 interact functionally and physically to confer disease resistance.

Plant resistance proteins of the class of nucleotide-binding and leucine-rich repeat domain proteins (NB-LRRs) are immune sensors which recognize pathogen-derived molecules termed avirulence (AVR) proteins. We show that RGA4 and RGA5, two NB-LRRs from rice, interact functionally and physically to mediate resistance to the fungal pathogen Magnaporthe oryzae and accomplish different functions in AVR recognition. RGA4 triggers an AVR-independent cell death that is repressed in the presence of RGA5 in both rice protoplasts and Nicotiana benthamiana. Upon recognition of the pathogen effector AVR-Pia by direct binding to RGA5, repression is relieved and cell death occurs. RGA4 and RGA5 form homo- and hetero-complexes and interact through their coiled-coil domains. Localization studies in rice protoplast suggest that RGA4 and RGA5 localize to the cytosol. Upon recognition of AVR-Pia, neither RGA4 nor RGA5 is re-localized to the nucleus. These results establish a model for the interaction of hetero-pairs of NB-LRRs in plants: RGA4 mediates cell death activation, while RGA5 acts as a repressor of RGA4 and as an AVR receptor.

Palmitoylation-dependent membrane localization of the rice resistance protein pit is critical for the activation of the small GTPase OsRac1.

Nucleotide binding domain and leucine-rich repeat (NLR)-containing family proteins function as intracellular immune sensors in both plants and animals. In plants, the downstream components activated by NLR family proteins and the immune response mechanisms induced by these downstream molecules are largely unknown. We have previously found that the small GTPase OsRac1, which acts as a molecular switch in rice immunity, is activated by Pit, an NLR-type resistance (R) protein to rice blast fungus, and this activation plays critical roles in Pit-mediated immunity. However, the sites and mechanisms of activation of Pit in vivo remain unknown. To clarify the mechanisms involved in the localization of Pit, we searched for consensus sequences in Pit that specify membrane localization and found a pair of potential palmitoylation sites in the N-terminal coiled-coil region. Although wild-type Pit was localized mainly to the plasma membrane, this membrane localization was compromised in a palmitoylation-deficient mutant of Pit. The palmitoylation-deficient Pit displayed significantly lower affinity for OsRac1 on the plasma membrane, thereby resulting in failures of the Pit-mediated cell death, the production of reactive oxygen species, and disease resistance to rice blast fungus. These results indicate that palmitoylation-dependent membrane localization of Pit is required for the interaction with and the activation of OsRac1 and that OsRac1 activation by Pit is vital for Pit-mediated disease resistance to rice blast fungus.

Sekiguchi lesion gene encodes a cytochrome P450 monooxygenase that catalyzes conversion of tryptamine to serotonin in rice.

Serotonin is a well known neurotransmitter in mammals and plays an important role in various mental functions in humans. In plants, the serotonin biosynthesis pathway and its function are not well understood. The rice sekiguchi lesion (sl) mutants accumulate tryptamine, a candidate substrate for serotonin biosynthesis. We isolated the SL gene by map-based cloning and found that it encodes CYP71P1 in a cytochrome P450 monooxygenase family. A recombinant SL protein exhibited tryptamine 5-hydroxylase enzyme activity and catalyzed the conversion of tryptamine to serotonin. This pathway is novel and has not been reported in mammals. Expression of SL was induced by the N-acetylchitooligosaccharide (chitin) elicitor and by infection with Magnaporthe grisea, a causal agent for rice blast disease. Exogenously applied serotonin induced defense gene expression and cell death in rice suspension cultures and increased resistance to rice blast infection in plants. We also found that serotonin-induced defense gene expression is mediated by the RacGTPase pathway and by the G alpha subunit of the heterotrimeric G protein. These results suggest that serotonin plays an important role in rice innate immunity.

Promotion and Upregulation of a Plasma Membrane Proton-ATPase Strategy: Principles and Applications.

Plasma membrane proton-ATPase (PM H+-ATPase) is a primary H+ transporter that consumes ATP in vivo and is a limiting factor in the blue light-induced stomatal opening signaling pathway. It was recently reported that manipulation of PM H+-ATPase in stomatal guard cells and other tissues greatly improved leaf photosynthesis and plant growth. In this report, we review and discuss the function of PM H+-ATPase in the context of the promotion and upregulation H+-ATPase strategy, including associated principles pertaining to enhanced stomatal opening, environmental plasticity, and potential applications in crops and nanotechnology. We highlight the great potential of the promotion and upregulation H+-ATPase strategy, and explain why it may be applied in many crops in the future.

Takedown of Yasui procedure due to closed ventricular septal defect.

A two and a half year old girl who had undergone the Yasui procedure as a neonate for ventricular septal defect, subaortic stenosis, and interrupted aortic arch underwent follow-up catheterization 2 years postoperatively. It showed that the neo-left ventricular tract reconstructed by Damus-Kaye-Stansel anastomosis had occluded due to closure of the ventricular septal defect and residual subaortic stenosis at the original left ventricular outflow tract. The patient therefore underwent takedown of the Yasui procedure.

Cloning of a cDNA encoding a NAD-dependent formate dehydrogenase involved in oxalic acid metabolism from the white-rot fungus Ceriporiopsis subvermispora and its gene expression analysis.

The authors have proposed previously that intracellular degradation of oxalic acid via formate to CO(2) occurs in the white-rot fungus Ceriporiopsis subvermispora. The formate degradation is catalyzed by NAD-dependent formate dehydrogenase (CsFDH). In this study, two cDNAs named CsFDH1 and CsFDH2 encoding CsFDH were cloned. Each cDNA consisting of 1077 bp encodes a mature protein composed of 358 amino acid residues. The amino acid sequences of the deduced CsFDH1 and CsFDH2 showed 99% identity to each other. The predicted molecular mass for each was 39.3 kDa, which was similar to that of CsFDH purified from the vegetative mycelia of Ceriporiopsis subvermispora (purified-CsFDH). The recombinant CsFDH1 and CsFDH2 expressed by Escherichia coli showed FDH activity with similar characteristics to the purified CsFDH. However, the amount of CsFDH1 transcript from the vegetative mycelia was 236-691 times greater than that of CsFDH2. Therefore, the results strongly suggest that CsFDH1, as compared with CsFDH2, predominantly contributes to the production of the purified CsFDH.

Risk factor of interim failure and early detection of the high-risk patients with functional single ventricle after Blalock-Taussing shunt.

PURPOSE: The purpose of this study was to identify the risk factor of interim failure and to consider the method for detecting high-risk patients after Blalock-Taussing shunt. METHODS: Between 1990 and 2004, 64 patients with functional single ventricle and low pulmonary flow underwent Blalock-Taussing shunt. We evaluated risk factors of interim failure by Logistic regression. Furthermore, assessments by catheterization and echocardiography were compared between Group Completion (Group C; 36 patients who had completed the Fontan operation or were Fontan candidates) and Group Failure (Group F; 20 patients who died before the Fontan operation or dropped out from Fontan candidate). RESULTS: In Group C, the survival at 10 years was 93%. The risk factor of interim failure was a systemic ventricular end-diastolic volume (SVEDV) of more than 250% of normal after shunt. The ventricular volume by echocardiography in Group C had been maintained between 190% and 200% of normal. By contrast, the ventricle in Group F had been significantly dilated after postshunt short term. CONCLUSIONS: The risk factor of interim failure was postshunt ventricular dilation, and the dilation was identified after postshunt short term. We recommend volume study within two to three months after shunt, and bidirectional cavopulmonary anastomosis should be immediately indicated to patients with ventricular dilation.

Creation of an intraatrial tunnel to produce a total cavo-pulmonary connection in a patient with dominant right ventricle, totally anomalous pulmonary venous connection, and pulmonary atresia with non-confluent pulmonary arteries.

The surgical strategy for patients having a functionally single ventricle associated with totally anomalous pulmonary venous connection and pulmonary atresia with non-confluent pulmonary artery has yet to be agreed. We created an intraatrial tunnel to produce a total cavo-pulmonary connection in such a patient, also creating a confluence for the pulmonary arteries. By minimizing the use of the GoreTex patch, the patient was able to discontinue the use of warfarin.

Development and progression of atherosclerotic disease in relation to insulin resistance and hyperinsulinemia.

It is unclear whether the role of insulin resistance in the development of atherosclerotic cardiovascular disease is similar in populations in which the incidence of atherosclerotic diseases significantly differs from that in Western countries. The aim of this study was to determine the relationship between insulin resistance and the development of cardiovascular disease in the Japanese population. We conducted 75 g-oral glucose tolerance tests (OGTTs) on 1,928 inhabitants of two towns in Hokkaido, Japan. Subjects using antihypertensive agents and known diabetic patients were excluded from the study. Data from the remaining 1,227 subjects (540 males and 687 females; mean age 56.0 +/- 10.8 years) were used for the analysis, and 1,051 subjects were seen in a follow-up care setting for a period of 8 years. The presence of insulin resistance was defined according to the guidelines reported our previous study: insulin levels of 64.0 mU/l or higher 2 h after the 75 g-OGTT. The insulin-resistant (IR) group had several risk factors such as hypertension, diabetes, treated or untreated hypercholesterolemia, hypertriglyceridemia, low high-density-lipoprotein (HDL) cholesterol levels, and obesity. During the follow-up period of 8 years, the incidence of coronary artery disease, which was adjusted for age, body mass index, sex, systolic blood pressure, fasting plasma glucose, total cholesterol, triglyceride, and HDL cholesterol was significantly (3.2 times) higher in the IR group than in the insulin non-resistant group. The results suggested that insulin resistance is an independent risk factor for coronary artery disease in Japanese subjects, as has also been demonstrated in the case of individuals in Europe and USA.

Biventricular repair of double-outlet right ventricle and closing ventricular septal defect.

We report an infant with double-outlet right ventricle and progressive left ventricular failure caused by a closing apical muscular ventricular septal defect detected during follow-up, who achieved successful biventricular repair after surgical opening and enlargement of a closed perimembranous ventricular septal defect.

Prevalence of asymptomatic arteriosclerosis obliterans and its relationship with risk factors in inhabitants of rural communities in Japan: Tanno-Sobetsu study.

OBJECTIVES: Since arteriosclerosis obliterance in the legs (ASO) causes deterioration of the prognosis of the elderly, prevention of ASO is important for maintenance of their quality of lives. We studied the prevalences of ASO in rural communities in Japan. METHODS AND RESULTS: We measured the ratio of systolic blood pressure in the leg to that in the arm (ABI) using a new device, Form PWV/ABI, in 1398 subjects of both sexes. Subjects with ABI values below 0.9 were considered to have ASO. The prevalence of ASO was 2.7% in all of the subjects, 1.0% in subjects under the age of 60 years, and 3.4% in subjects aged 65 years or more. Multiple regression analysis showed that ABI was correlated with plasma level of total cholesterol in men. There were no significant differences of the mean age, mean fasting plasma glucose level and percentage of patients who smoked between the ASO group and non-ASO group in each sex. Mean cholesterol level in our subjects is lower than the reported levels in Europeans and Americans. The prevalence of ASO increased with increase in the number of risk factors in individual subjects. CONCLUSIONS: Among the atherosclerotic risk factors, age and total cholesterol seem to be more important risk factors of ASO than others.

Coronary stent implantation in patients with a single coronary artery--a report of 3 cases.

An isolated single coronary artery is a rare congenital anomaly and a cause of cardiac ischemia, congestive heart failure, and sudden cardiac death. Reported here are 3 cases of single coronary artery with acute myocardial infarction in which coronary stenting was performed. Also reported are the coronary blood flow patterns of the right coronary artery arising from the single left coronary artery.

[Relation of hypertension and glucose tolerance impairment in elderly people to the development of arteriosclerosis--investigation using pulse wave velocity].

Hypertension and diabetes are risk factors for arteriosclerosis and have a synergistic effect on the progression of arteriosclerosis. The aim of this study was to determine the correlation between complications of hypertension and diabetes and arteriosclerosis as assessed by pulse wave velocity (PWV) in elderly subjects. The subjects of this study were 186 people aged 60 years or older (mean age: 68.8 +/- 5.8 years) who were scheduled to undergo health examinations. PWV, systolic blood pressure (SBP), diastolic blood pressure (DBP), body mass index (BMI), fasting blood sugar (FBS), total cholesterol (TC), triglyceride (TG) and HDL cholesterol (HDL) were measured in each subject. The patients were divided according to the American Diabetes Association (ADA) diagnostic criteria for diabetes based on fasting blood sugar level into the following three groups: a normal (NGT) group (FBS < 110 mg/dl), an impaired fasting glucose (IFG) group (110 < or = FBS < 126 mg/dl) and a diabetes mellitus (DM) group (FBS > or = 126 mg/dl or receiving treatment for diabetes). Based on the JNC-VI and WHO/ISH diagnostic criteria, subjects who had a SBP of 140 mmHg or higher or a DBP of 90 mmHg or higher or who had been taking hypotensive drugs were assigned to the hypertension (HT) group, and the other subjects were assigned to the normotension (NT) group. PWV showed significant positive correlations with SBP and FBS (r = 0.499 and r = 0.300, respectively). The effects of hypertension on PWV were significantly higher in subjects with HT than in subjects with NT in all of the glucose tolerance groups (all p < 0.01). Moreover, in the subjects with HT, PWV started to increase from the IFG stage, and PWV was significantly higher in the DM groups than in the NGT group (p < 0.01). In multiple regression analysis using PWV as an objective variable, SBP and FBS were selected as significant explanatory variables. The results of this study indicate the need for stricter management of elderly people with slight glucose tolerance impairment and hypertension in order to prevent the occurrence of arteriosclerosis.

[Adiponectin levels and coronary risk factors in the elderly].

AIM: To determine the relationship between adiponectin level and coronary risk factors in men. METHODS: The subjects were 395 elderly men in two rural communities (Tanno, Sobetsu) in Japan. Blood pressure in the sitting position (SBP/DBP), after overnight fasting, plasma glucose level (FPG), total cholesterol (TC), triglyceride (TG), HDL cholesterol (HDL) and serum adiponectin were measured. The subjects were divided into two adiponectin level groups, a high adiponectin level (> or = 7.94 microg/ml) group (H-Adipo group) and a normal adiponectin level (< 7.94 microg/ml) group (N-Adipo group), and into two age groups, 70 years of age or older (70 or older group) and less than 70 years of age (under 70 group). RESULTS: Adiponectin showed negative correlations with BMI, FPG, TC and TG and positive correlations with age, SBP and HDL. In multiple regression analysis using adiponectin as a dependent variable. BMI, SBP, FPG, TG and HDL were selected as independent variables. Age and HDL in the H-Adipo group were significantly higher than those in the N-Adipo group, and BMI, FPG, TC and TG in the H-Adipo group were significantly lower than those in the N-Adipo group. In the 70 or older group. SBP and adiponectin were significantly higher and BMI, DBP, FPG, TC and TG were significantly lower than those in the under 70 group. The mean number of total coronary risk factors in the 70 or older group (1.71) was significantly lower than that in the under 70 group (2.06). CONCLUSIONS: Coronary risk factors other than systolic blood pressure were significantly reduced in the older subjects.

Successful biventricular repair of double-outlet right ventricle with transposition of the great arteries, pulmonary stenosis, and straddling mitral valve.

A 9-month-old boy with polysplenia, double-outlet right ventricle (DORV), transposition of the great arteries (TGA), a large ventricular septal defect (VSD), straddling mitral valve, pulmonary stenosis (PS), and a normal-sized pulmonary annulus underwent ventricular septation at the right side of the straddling mitral chord as well as an en bloc truncal switch procedure to minimize reduction of right ventricular (RV) volume from the intraventricular conduit. Echocardiography 5 months postoperatively showed laminar flow without obstruction through both ventricular outflow tracts, normal ventricular function, trivial aortic regurgitation, and mild pulmonary regurgitation (PR). This procedure is a good option for biventricular repair in the presence of a straddling mitral valve.

Case of congenital aneurysm of sinus of Valsalva with common arterial trunk.

We describe an unusual case of a patient with common arterial trunk and interrupted aortic arch, complicated by congenital aneurysm of the sinus of Valsalva, who underwent successful repair. To our knowledge, no such case has been reported in the English literature. The combination of common arterial trunk and congenital aneurysm of the sinus of Valsalva may yield insights into the morphogenesis of congenital aneurysm of the sinus of Valsalva.