Mode of Delivery and Neonatal Outcome in Adolescent Pregnancy (13-16 Years Old) Associated with Anemia.

Background: Adolescent pregnancy represents an important public-health problem due to its maternal and fetal outcomes. Adolescent patients are predisposed to multiple obstetrical complications, including anemia and preterm birth which has a higher incidence among this population; withal, in the specialty literature, anemia is considered to be a risk factor for preterm delivery; furthermore, multiple studies have demonstrated that a very young age is an independent risk factor for preterm birth. Objectives: The study aims to reveal if anemia during adolescent pregnancy has a negative impact on the time and mode of delivery and newborns' outcomes. Patients and methods: We performed a retrospective multicentric study on adolescent pregnancy. We analyzed 172 patients aged between 13 and 16 years who delivered in two large tertiary hospitals between 1 October 2018 and 15 April 2022. We divided the patients into two groups­a study group (n = 64) with anemia and a control group (n = 108) without anemia. We evaluated the modes of delivery, the times of birth, and the neonatal outcomes by 1-min newborn's Apgar score, neonatal intensive-care unit (NICU) admission, and the newborns' weights. Results: The rate of cesarean section was higher in patients with anemia than in the control group (45.31% vs. 38.88%, p < 0.001). We found that patients between 13 and 16 years diagnosed with anemia have a higher risk of preterm birth than those without anemia (35.93% vs. 21.29%, p < 0.001); however, an increased rate of LBW neonates was observed in the anemic adolescent group ≤14 years (p < 0.001). Regarding the newborns' 1-min Apgar score, NICU admission, no statistically significant differences were recorded between the two groups according to the severity of anemia. In the anemic patients' group, prenatal screening was identified in 9.37% of cases, while in the control group, in 16.67% (p = 0.034), which represents negative predictive factors, along with a low socio-economic status for the presence of anemia in young adolescent patients. Conclusions: Anemia is a risk factor for preterm birth, LBW, and cesarean section in young adolescent pregnancy. The association of lack of prenatal care and low socio-economic status worsens maternal and neonatal outcomes.

SARS-CoV-2 Infection during Pregnancy and Histological Alterations in the Placenta.

(1) Background: Despite the high number of cases of COVID-19 during pregnancy, SARS-CoV-2 congenital infection is rare. The role of the placenta as a barrier preventing the transmission of SARS-CoV-2 from the mother to the fetus is still being studied. This study aimed to evaluate the impact of SARS-CoV-2 infection on placental tissue. (2) Methods: This was a transversal monocentric observational study. In the study, we included pregnant women with COVID-19 who delivered at "Sfântul Pantelimon" Clinical Emergency Hospital between 1 April 2020 and 30 March 2022. Histological analyses, both macroscopic and microscopic, were performed for placentas that came from these cases. (3) Results: To date, a characteristic placental lesion has not been clearly demonstrated, but most findings include features of maternal and fetal vascular malperfusion, which probably reflect the reduction in placental blood flow due to low oxygen level from the hypoxic respiratory disease and underlying hypercoagulable state induced by the COVID-19 infection. (4) Conclusions: The histopathological aspects found in placentas that came from COVID-19-positive pregnant women are common for many other diseases, but when they are found together, they are highly suggestive for viral infectious involvement of the placenta.

The Risk of Obstetrical Hemorrhage in Placenta Praevia Associated with Coronavirus Infection Antepartum or Intrapartum.

Background and Objectives: The aim was to evaluate the severity of obstetrical bleeding in the third trimester associated with COVID infection in placenta previa and accreta. Materials and Methods: A retrospective study was conducted to compare the risk of obstetrical bleeding in the case of placenta previa with or without associated SARS-CoV-2 infection. Patients presenting with placenta previa before labor were classified into three groups: group A (control) as no infection throughout their pregnancy, group B as confirmed infection during the 1st trimester, and group C as confirmed infection at the time of delivery. Infected patients were stratified according to the severity of signs and symptoms. The severity of obstetrical hemorrhage at birth was assessed quantitatively and qualitatively. All placentas were analyzed histologically to identify similarities. Results: Prematurity and pregnancy-induced hypertension appear significantly related to SARS-CoV-2 infection during the 3rd trimester. Placenta accreta risk increases significantly with infection during the 1st trimester. No statistically significant differences in the severity of hemorrhage associated with childbirth in cases with placenta previa between groups A and C but increased obstetrical bleeding mainly due to emergency hemostatic hysterectomy in group B driven by placenta accrete were detected. Obstetrical hemorrhage at birth in the case of coexistence of the infection was found not to correlate with the severity of the viral disease. Meanwhile, the number of days of hospitalization after birth is related to the specific treatment of COVID infection and not related to complications related to birth. Conclusions: The study finds an increased incidence of placenta accreta associated with placenta previa in cases where the viral infection occurred in the first trimester of pregnancy, associated with an increased incidence of hemostasis hysterectomies in these patients. Placental histological changes related to viral infection are multiple and more important in patients who had COVID infection in the first trimester.

Ectopic Intrauterine Device Revealed by Ureteral Colic in a 37-Week Pregnant Woman: Case Report.

Copper T intrauterine devices (IUDs) are a popular long-acting reversible contraceptive method. The most common reasons for contraceptive failure are expulsion and extrauterine migration. We report a case of a 28-year-old female, G13P3, 37 weeks pregnant, who presented to the hospital for left abdominal flank pain. The patient was admitted for treatment of left ureteral colic. The woman went into labour, and Caesarean Section was performed due to foetal distress. During the surgery, an inspection of the peritoneal cavity revealed a copper IUD embedded in the granulous tissue located in the left lateral abdominal region, which was extracted. No uterine scar tissue could be identified macroscopically. The migration of an IUD in the abdominal cavity is a rare finding, and coexistence with third-trimester pregnancy is an infrequent but serious event due to potential visceral complications. Higher gravidity can be associated with an increased risk of IUD migration in women with a non-scarred uterus.

Catalytic Enantioselective Birch-Heck Sequence for the Synthesis of Phenanthridinone Derivatives with an All-Carbon Quaternary Stereocenter.

Novel phenanthridinone analogues with an all-carbon quaternary stereocenter have been enantioselectively synthesized using the Birch-Heck sequence. Flat phenanthridinone structures have extensive bioactivity but consequently also suffer from poor therapeutic selectivity. The addition of a quaternary center to the phenanthridinone skeleton has the potential to generate more complex analogues with improved selectivity. Unfortunately, no general synthetic pathway to such derivatives exists. Herein we report a four-step process that transforms inexpensive benzoic acid into 22 different quaternary carbon-containing phenanthridinone analogues with a variety of substituents on all three rings: alkyl groups at the quaternary center; methyl, methoxymethyl, or para-methoxybenzyl on the amide nitrogen; and halogen and methyl substituents on the aryl ring. Good to very good enantioselectivity was demonstrated in the key intramolecular desymmetrizing Mizoroki-Heck reaction. Transformations of the Heck reaction products into molecules with potentially greater therapeutic relevance were also accomplished.

Prognostic value of the location of submucosal uterine leiomyomas in infertility.

Submucosal fibroid location and size are predictive factors of impaired fertility. Submucosal fibroids cause infertility through several mechanisms including distortion of the endometrial cavity, increased uterine contractility, local inflammation and remodeling of the endometrial blood supply. This is a monocentric, retrospective, cross-sectional study, conducted in the Department of Obstetrics and Gynecology of 'Sf. Pantelimon' Clinical Emergency Hospital, analyzing patients from a 5-year period (January 2015-December 2019). In the present study, the relationship between different characteristics of the submucosal fibroids (among others, location and dimensions) and fertility (birth rates, early pregnancy loss rates) were investigated. This study identified that submucosal and intramural fibroids are risk factors for reduced birth rate compared with subserosal fibroids (P=0.02, RR=2.58, 95% CI 1.03-6.47; P=0.005, RR=1.18, 95% CI 1.02-1.35, respectively). In addition, G2 leiomyomas are risk factors for low birth rate compared with G0 and G1 fibroids (P=0.01, RR=1.95, 95% CI 1.05-3.60). Moreover, the presence of a subserosal fibroid was associated with an increased early pregnancy loss rate (P=0.01, RR=2.14, 95% CI 1.05-4.35). In conclusion, the location and degree of uterine cavity distortion are important factors that alter the normal development of a pregnancy and the birth rate.

Obstetrical Soft Tissue Trauma during Spontaneous Vaginal Birth in the Romanian Adolescent Population-Multicentric Comparative Study with Adult Population.

Romania is a country with high rates of adolescent births, associating scarce comprehensive obstetrical management with this specific population. This research aims to assess soft tissue trauma after vaginal birth in teenage mothers compared to their adult counterparts. A retrospective case-control study was conducted for one year in two hospitals. All vaginal deliveries were considered; the age cut-off value was considered at 20 years old for case and control groups. Lacerations were divided into three subgroups, considering the involved anatomical region; group I: labial and periurethral lacerations, group II: vaginal and perineal lacerations, and group III: cervical lacerations. There were 1498 women included in the study: 298 young mothers and 1200 adults. Teenagers were more likely to have an episiotomy during vaginal delivery compared to adult women: 56% versus 26.7% (p = 0.00, Pearson Chi-square) and a 1.89 times increased risk for developing additional group II lacerations: p = 0.01, Pearson Chi-square test with Bonferroni correction: OR = 1.89, 95% CI: 1.18-3.02. Group II lacerations were the most frequent type of birth trauma in both study groups. Fetal weight ≥4000 g was associated with a two times higher risk for vaginal and perineal lacerations when age criterion was not considered (OR = 1.98, 95% CI: 1.13-3.47, p = 0.01). The incidence of group I and II lacerations increased with age: from 0% and 9.1% between 10 and 14 years old to 6% and 26.2% between 18 and 19 years old. All groups of lacerations were more often identified in the case group, compared to the adult group. Fetal macrosomia and spontaneously ruptured membranes at admission could not be documented as risk factors for obstetrical injury in young mothers. Episiotomy performed in teenagers was not a protective procedure for group II lacerations.

Investigating Caesarean Section Practice among Teenage Romanian Mothers Using Modified Robson Ten Group Classification System.

The Robson ten-group classification system is a recognized effective method of assessing caesarean rate. It is based on dividing patients into ten mutually exclusive groups, focusing on six maternal and newborn variables (parity, gestational age, plurality, foetal presentation, previous caesarean, and mode of labour onset). The aim of our analysis was twofold: first, to present the implementation of Robson classification in a pregnant teenage population; and second, to identify the indications for CS in the adolescent population. This study was designed as a one-year prospective analysis and considered all women younger than 20 years of age who delivered in a tertiary care hospital. Before discharge, women who had caesarean delivery responded to a questionnaire regarding their education, prenatal surveillance, and obstetrical history. Caesarean sections accounted for 47.01% of all births. A proportion of 24.57% of the participants had at least one previous caesarean section. Group 10 (all women with a single cephalic preterm pregnancy) was second most often identified among women in middle adolescence (14.03%); 32.20% of the participants in late adolescence were in group 5 (multiparas with a scarred uterus, single cephalic term pregnancy). Differences between the two age groups were not statistically different (p = 0.96). Abnormal cardiotocographic findings (38.23%), the arrest of descent (19.11%) and arrest of dilation (19.11%), were the most frequent indications for caesareans in Robson group 1. Neonates from mothers in Robson groups 8 (women with a multiple pregnancy) and 7 (multiparas single breech pregnancy) had the most unfavourable outcomes regarding gestational age at delivery and admission to the intensive care unit. We concluded that future focus on obstetrical management is mandatory in Robson groups 7 and 8. Adolescents in Robson group 1 (nulliparas, single cephalic term pregnancy, spontaneous labour) are the primary beneficiaries of strategies to reduce caesarean sections rates.

Assessment of Postpartum Depression in Adolescents Who Delivered during COVID-19 Social Restrictions: The Experience of a Tertiary Hospital from Bucharest, Romania.

In the context of the viral spread of COVID-19 in 2020, Romanian authorities declared national confinement for two months. Our country faces a public health issue regarding adolescent pregnancy. This study assessed the predisposition of teenage mothers to postpartum depression and the influence of the viral pandemic on their emotional status. This study enrolled patients 10 to 19 years old who delivered in our department between March-December 2020. Teenagers were attributed to the "lockdown group" (n = 30) and the "open group" (n = 171). All study participants agreed to take an interview based on a three-part questionnaire, including the Edinburgh Postnatal Depression Scale (EPDS). In the "lockdown group", 16.67% of patients felt stressed over the last year compared to 11.11% of individuals in the "open group", but there was no statistically significant difference between groups regarding overall EPDS scores (z value 0.51, Mann-Whitney U test). Predictable variables for postpartum depression were the use of cigarettes (OR = 1.08, 95% CI: 1.00-1.16), intended pregnancies (OR = 0.25, 95% CI: 0.09-0.68, p = 0.007) and absence of stressors in the last year (OR = 0.07, 95% CI: 0.02-0.30, p = 0.0002). More adolescents were stressed during confinement compared to those who delivered in the following time period; this aspect did not interfere with depression screening scores. A planned pregnancy, even during adolescence, can serve as a protective factor for postpartum depression.

Insights on Hysteroscopic Procedures and Their Place in Romanian Gynecologic Practice-The Experience of Two Medical Units.

Hysteroscopy has known an increasing use in Romania over the last decade, succeeding to mark an impact on lowering the costs of medical services. The strategy of this study was to present the experience of two Romanian medical units with different experiences using inpatient regimen hysteroscopy, and to further compare it with current worldwide tendencies. Strong points in our practice were sought, as well as components that require improvement. Overall, abnormal uterine bleeding stands for most hospital case presentations in our study group; hysteroscopy had the highest accuracy and positive predictive value in identifying uterine myomas: 91.03% and 100%, respectively; for endometrial polyps, statistical analysis showed the highest sensitivity: 100%, with 83.89% specificity and a 77.64% positive predictive value. The applicability of hysteroscopy was further described for infertility cases and isthmocele repair.

Cell type specific transcriptional reprogramming of maize leaves during Ustilago maydis induced tumor formation.

Ustilago maydis is a biotrophic pathogen and well-established genetic model to understand the molecular basis of biotrophic interactions. U. maydis suppresses plant defense and induces tumors on all aerial parts of its host plant maize. In a previous study we found that U. maydis induced leaf tumor formation builds on two major processes: the induction of hypertrophy in the mesophyll and the induction of cell division (hyperplasia) in the bundle sheath. In this study we analyzed the cell-type specific transcriptome of maize leaves 4 days post infection. This analysis allowed identification of key features underlying the hypertrophic and hyperplasic cell identities derived from mesophyll and bundle sheath cells, respectively. We examined the differentially expressed (DE) genes with particular focus on maize cell cycle genes and found that three A-type cyclins, one B-, D- and T-type are upregulated in the hyperplasic tumorous cells, in which the U. maydis effector protein See1 promotes cell division. Additionally, most of the proteins involved in the formation of the pre-replication complex (pre-RC, that assure that each daughter cell receives identic DNA copies), the transcription factors E2F and DPa as well as several D-type cyclins are deregulated in the hypertrophic cells.

A rare case of synchronous ovarian tumors: clinical case report and literature review.

Epithelial ovarian carcinoma makes up 90-95% of all ovarian malignancies, taking into account also low-malignant-potential tumors. The Krukenberg tumor is a rare metastatic adenocarcinoma (ADK) in the ovary, representing 1-2% of ovarian tumors. Multiple primary malignant neoplasms may exist when more than one cancerous tumor is diagnosed in the same or a different organ. The incidence of multiple primary cancers among malignancies is between 2.4% to 8%. The aim of this paper is to report the case of a 47-year-old patient with two synchronous malignant tumors involving both ovaries, one diagnosed as primary papillary serous cystadenocarcinoma and the other one diagnosed as ovarian metastasis (Krukenberg tumor) of a synchronous colorectal ADK, and the complex diagnostic and therapeutic challenges that such a rare case poses. Histopathological (HP) examination and especially the immunohistochemical analysis had a determining role in differentiating between an ovarian primary tumor and a metastasis from a gastrointestinal tract cancer. The tumors examination for somatic mutations of Kirsten rat sarcoma viral oncogene homolog (KRAS) and neuroblastoma RAS viral oncogene homolog (NRAS) genes was performed in order to individualize the chemotherapic treatment in this difficult case. The conclusion of this case is that, although synchronous multiple primary cancers in a young patient are a rare condition, this situation should be taken into account in the differential diagnosis when we encounter clinical and HP diagnostic challenges.

The problems associated with adolescent pregnancy in Romania: A cross-sectional study.

RATIONALE: The extent of pregnancy in adolescents and young adults, especially in low and middle-income countries, is a source of increasing concern given its social and economic impact. AIMS AND OBJECTIVE: We hypothesized that there would be correlations between female patients becoming pregnant at a young age and practices such as harmful alcohol misuse, cigarette smoking, and drug use, the use of toxic substances, low educational attainment, and an essential absence of health care seeking about the outcome of adolescent pregnancies. METHODS: We performed a prospective cross-sectional study of patients who gave birth between August and November 2017 at St. Pantelimon Emergency Hospital in Bucharest, Romania. Seventy-four patients aged 14 to 20 years, with a mean maternal age of 18.07 years, were enrolled in the study and answered a 15-item questionnaire about their social, educational, and medical background. RESULTS: Fifty-three patients (71.6%) gave birth by caesarean section and 21 (28.3%) by vaginal delivery. Notably, patients aged 14 to 16 years had a lower rate of caesarean delivery compared with those aged 17 to 20 years. Moreover, 83.0% of the caesarean sections and 76.1% of the vaginal deliveries were at term. With reference to age and type of delivery, women are more likely to give birth by caesarean section at any age group (the association is not statistically significant at P < .05), except for the age of 15 years (five out of six patients in our sample had a spontaneous birth). Smoking was the most common risk behavior in the sample (45.9%, n = 34), followed by alcohol consumption (17.5%, n = 13) and drug use (5.40%, n = 4). CONCLUSIONS: A high percentage of caesarean delivery was reported, particularly in patients aged >17 years. The percentage of female participants who underwent a caesarean delivery for their second pregnancy was significantly higher than compared with primipara participants. Patients receiving consistent antenatal care visits compared with those who did not monitor their pregnancy did not differ in the likelihood of undergoing a caesarean section.

Correlation of ultrasound features and the Risk of Ovarian Malignancy Algorithm score for different histopathological subtypes of benign adnexal masses.

Ovarian masses are one of the most frequently identified entities in gynecological practice. Early differential diagnosis is a key factor in the medical management of each patient. Transvaginal ultrasound along with additional preoperative testing, such as serum cancer antigen 125 (CA-125) levels and the Risk of Ovarian Malignancy Algorithm (ROMA) score, usually provide sufficient information for a presumptive diagnosis. Minimally invasive surgery as a therapeutic approach is the standard procedure for uncomplicated and benign adnexal masses. Histopathological examination alone, or in conjunction with immunohistochemical testing establishes a more certain diagnosis in the final step of the patient management plan. We developed a retrospective descriptive observational study based on the evaluation of 107 patients admitted to the Department of Obstetrics and Gynecology at "Sf Pantelimon" Clinical Emergency Hospital in Bucharest between January 2000 and July 2017. Each patient was diagnosed with an ovarian mass and underwent laparoscopic surgery for treatment. All data underwent descriptive statistical analysis in order to establish correlations between preoperative test results and definitive diagnoses. The typical ultrasound findings of endometriotic cysts were histopathologically confirmed in 52.6% of the examined patients. Using ultrasound, benign teratomas were suspected in 66.6% of all documented dermoid cysts and 90% of the patients with a calculated ROMA score had corresponding values less than 15%. Mean CA-125 value was 26.58 U/mL. Laparoscopic surgery with ovarian cystectomy was performed for 78.5% of the cases. Histopathological examinations established endometriosis was present in 26.16% of cases. According to an independent samples t test (with 2 extreme values eliminated), patients in the premenopausal group had a significantly lower mean ROMA score than postmenopausal patients (6.87% vs 20.98%, respectively; P < .001). The groups had similar homogeneity (P = .131 according to the Levene test). Our results showed that transvaginal ultrasound established a presumptive diagnosis for almost half of our patients. Cystectomy was the main surgical procedure used for the management of benign ovarian masses. Endometriosis was the most common benign ovarian pathology evaluated and treated in our study.

Alobar holoprosencephaly associated with a rare chromosomal abnormality: Case report and literature review.

RATIONALE: Holoprosencephaly is a structural malformation of the brain that results from the complete or incomplete noncleavage of the forebrain of the embryo into 2 hemispheres. We report a severe case of alobar holoprosencephaly diagnosed at 38 weeks, associated with cebocephaly, microcephaly, and craniosynostosis. PATIENT CONCERN: The main knowledge added by this case is the late ultrasound diagnosis and chromosomal analysis that revealed a very rare abnormality (45X/46,XX/47,XX) with mosaicism at chromosome 18. DIAGNOSES: Investigation of the mother revealed nothing remarkable from clinical point of view and on laboratory tests. Ultrasonography identified a fetal biometry appropriate for gestational age, except for the head biometry and abdominal circumference, that were appropriate for less than the fifth percentile. Microcephaly, a large midline monoventricle, absent midlinestructures, cleft lip, cebocephaly (hypotelorism, single-nostril nose), ethmocephaly (hypotelorism, interorbital proboscis) and craniosynostosis, were also present. Fetal magnetic resonance imaging of fetus revealed an absent midline structure, a central monoventricle, abnormal corpus calosum, and abnormal gyri. INTERVENTIONS: A cesarean section at 38 weeks was indicated for fetal bradycardia and a female baby was delivered, with Apgar score 6, weight 2290g. After birth, the diagnosis of the fetus confirmed holoprosencephaly with facial anomalies and demonstrated repeated tonic-clonic seizure, severe respiratory failure, cyanosis, decreased muscle tone, palor, and apnea. Laboratory examination of the newborn revealed acidosis and a prolonged of prothrombin time. The neonate was treated for severe respiratory distress syndrome, with immediate intubation and resuscitation. Vitamin K, fresh frozen plasma, and antibiotics were also administered. OUTCOMES: After delivery, exitus of the fetus occurred at 3 days and 18hours due to massive pulmonary hemorrhage. LESSONS: We described a case of alobar holoprosencephaly diagnosed at 38 weeks of gestation and associated with a rare chromosomal abnormality (45X/46,XX/47,XX) with mosaicism at chromosome 18. Emotional implications could have been less severe if the patient underwent regular ultrasonography allowing a diagnosis in the first or early second trimester.

How to make a tumour: cell type specific dissection of Ustilago maydis-induced tumour development in maize leaves.

The biotrophic fungus Ustilago maydis causes smut disease on maize (Zea mays), which is characterized by immense plant tumours. To establish disease and reprogram organ primordia to tumours, U. maydis deploys effector proteins in an organ-specific manner. However, the cellular contribution to leaf tumours remains unknown. We investigated leaf tumour formation at the tissue- and cell type-specific levels. Cytology and metabolite analysis were deployed to understand the cellular basis for tumourigenesis. Laser-capture microdissection was performed to gain a cell type-specific transcriptome of U. maydis during tumour formation. In vivo visualization of plant DNA synthesis identified bundle sheath cells as the origin of hyperplasic tumour cells, while mesophyll cells become hypertrophic tumour cells. Cell type-specific transcriptome profiling of U. maydis revealed tailored expression of fungal effector genes. Moreover, U. maydis See1 was identified as the first cell type-specific fungal effector, being required for induction of cell cycle reactivation in bundle sheath cells. Identification of distinct cellular mechanisms in two different leaf cell types and of See1 as an effector for induction of proliferation of bundle sheath cells are major steps in understanding U. maydis-induced tumour formation. Moreover, the cell type-specific U. maydis transcriptome data are a valuable resource to the scientific community.

Insights into Host Cell Modulation and Induction of New Cells by the Corn Smut Ustilago maydis.

Many filamentous fungal pathogens induce drastic modulation of host cells causing abnormal infectious structures such as galls, or tumors that arise as a result of re-programming in the original developmental cell fate of a colonized host cell. Developmental consequences occur predominantly with biotrophic phytopathogens. This suggests that these host structures result as an outcome of efficient defense suppression and intimate fungal-host interaction to suit the pathogen's needs for completion of its infection cycle. This mini-review mainly summarizes host cell re-programming that occurs in the Ustilago maydis - maize interaction, in which the pathogen deploys cell-type specific effector proteins with varying activities. The fungus senses the physiological status and identity of colonized host cells and re-directs the endogenous developmental program of its host. The disturbance of host cell physiology and cell fate leads to novel cell shapes, increased cell size, and/or the number of host cells. We particularly highlight the strategies of U. maydis to induce physiologically varied host organs to form the characteristic tumors in both vegetative and floral parts of maize.

Chitin-induced and CHITIN ELICITOR RECEPTOR KINASE1 (CERK1) phosphorylation-dependent endocytosis of Arabidopsis thaliana LYSIN MOTIF-CONTAINING RECEPTOR-LIKE KINASE5 (LYK5).

To detect potential pathogens, plants perceive the fungal polysaccharide chitin through receptor complexes containing lysin motif receptor-like kinases (LysM-RLKs). To investigate the ligand-induced spatial dynamics of chitin receptor components, we studied the subcellular behaviour of two Arabidopsis thaliana LysM-RLKs involved in chitin signalling, CHITIN ELICITOR RECEPTOR KINASE1 (CERK1) and LYSIN MOTIF-CONTAINING RECEPTOR-LIKE KINASE5. We performed standard and quantitative confocal laser scanning microscopy on stably transformed A. thaliana plants expressing fluorescently tagged CERK1 and LYK5 from their native promoters. Microscopy approaches were complemented by biochemical analyses in plants and in vitro. Both CERK1 and LYK5 localized to the plasma membrane and showed constitutive endomembrane trafficking. After chitin treatment, however, CERK1 remained at the plasma membrane while LYK5 relocalized into mobile intracellular vesicles. Detailed analyses revealed that chitin perception transiently induced the internalization of LYK5 into late endocytic compartments. Plants that lacked CERK1 or expressed an enzymatically inactive CERK1 variant did not exhibit chitin-induced endocytosis of LYK5. CERK1 could phosphorylate LYK5 in vitro and chitin treatment induced CERK1-dependent phosphorylation of LYK5 in planta. Our results suggest that chitin-induced phosphorylation by CERK1 triggers LYK5 internalization. Thus, our work identifies phosphorylation as a key regulatory step in endocytosis of plant RLKs and also provides evidence for receptor complex dissociation after ligand perception.

Cell biology of corn smut disease-Ustilago maydis as a model for biotrophic interactions.

Ustilago maydis is a well-established model system for biotrophic fungal plant pathogens. The fungus has a dimorphic life cycle with a yeast-like saprophytic phase switching to filamentous, pathogenic growth upon hyphal fusion. Due to its highly differentiated development and the amenability for reverse-genetics U. maydis provides a model system for both fungal cell biology as well as the study of biotrophic plant interaction. The present article highlights key findings in different aspects of cell biology on the corn smut disease and provides an outlook on the most intriguing open questions.

The fungal core effector Pep1 is conserved across smuts of dicots and monocots.

The secreted fungal effector Pep1 is essential for penetration of the host epidermis and establishment of biotrophy in the Ustilago maydis-maize pathosystem. Previously, Pep1 was found to be an inhibitor of apoplastic plant peroxidases, which suppresses the oxidative burst, a primary immune response of the host plant and enables fungal colonization. To investigate the conservation of Pep1 in other pathogens, genomes of related smut species were screened for pep1 orthologues. Pep1 proteins were produced in Escherichia coli for functional assays. The biological function of Pep1 was tested by heterologous expression in U. maydis and Hordeum vulgare. Pep1 orthologues revealed a remarkable degree of sequence conservation, indicating that this effector might play a fundamental role in virulence of biotrophic smut fungi. Pep1 function and its role in virulence are conserved in different pathogenic fungi, even across the monocot-dicot border of host plants. The findings described in this study classify Pep1 as a phylogenetically conserved fungal core effector. Furthermore, we documented the influence of Pep1 on the disease caused by Blumeria graminis f. sp. hordei which is a non-smut-related pathosystem.