Proteomic profile of tepary bean seed storage proteins in germination with low water potential.

BACKGROUND: Tepary bean (Phaseolus acutifolius A. Gray) is one of the five species domesticated from the genus Phaseolus with genetic resistance to biotic and abiotic stress. To understand the mechanisms underlying drought responses in seed storage proteins germinated on water and polyethylene glycol (PEG-6000) at -0.49 MPa, we used a proteomics approach to identify potential molecular target proteins associated with the low water potential stress response. METHODS: Storage proteins from cotyledons of Tepary bean seeds germinated at 24, 48 and 72 h on water and PEG-6000 at -0.49 MPa were analyzed by one-dimensional electrophoresis (DE) with 2-DE analysis and shotgun mass spectrometry. Using computational database searching and bioinformatics analyses, we performed Gene Ontology (GO) and protein interactome (functional protein association network) String analyses. RESULTS: Comparative analysis showed that the effect of PEG-6000 on root growth was parallel to that on germination. Based on the SDS‒PAGE protein banding patterns and 2-DE analysis, ten differentially abundant seed storage proteins showed changes in storage proteins, principally in the phaseolin and lectin fractions. We found many proteins that are recognized as drought stress-responsive proteins, and several of them are predicted to be intrinsically related to abiotic stress. The shotgun analysis searched against UniProt's legume database, and Gene Ontology (GO) analysis indicated that most of the seed proteins were cytosolic, with catalytic activity and associated with carbohydrate metabolism. The protein‒protein interaction networks from functional enrichment analysis showed that phytohemagglutinin interacts with proteins associated with the degradation of storage proteins in the cotyledons of common bean during germination. CONCLUSION: These findings suggest that Tepary bean seed proteins provide valuable information with the potential to be used in genetic improvement and are part of the drought stress response, making our approach a potentially useful strategy for discovering novel drought-responsive proteins in other plant models.

Pediatric Burn Care: How Burn Camps Survived and Thrived During the Coronavirus Pandemic.

Burn camps play a vital role in the recovery of burn survivors by allowing them to develop the confidence and skill sets needed to reintegrate back into society. During the COVID-19 pandemic, burn camps across the United States and Canada could not hold any in-person activities. They had to either pause burn camps or quickly adapt to a virtual online platform. A 37-item electronic survey was developed and emailed to burn camp directors in the United States and Canada to determine what adaptations were necessary during the pandemic. This survey allowed directors to provide details on many facets such as camp format, successes observed, and challenges encountered. Twenty-one of 34 (62%) burn camp organizations completed the survey. Thirteen of the 21 (62%) respondents held virtual burn camps in 2020 while everyone else canceled their camps in 2020. The mean number of camps offered per organization decreased from 6.3 in 2019 to 4.7 in 2020. The average number of burn survivors and family members participating also dropped in that same period (2019 aggregate mean = 229.2 vs 2020 aggregate mean = 151.4). Components of virtual camp included video conferencing platforms, "camp-in-a-box" activities, and some prerecorded sessions. Most camp directors believed that their campers were satisfied with the virtual format. Factors allowing for a successful virtual camp included an effective online platform, scheduling adequate duration of programs, and appropriate staffing levels. Most common barriers to an effective virtual camp were participant engagement, special needs/accessibility concerns, and staff effectiveness in this format. While challenging, burn camps can be held in a virtual format successfully with proper planning, staff training, and support of campers and their families.

Rib Plating as an Effective Approach to Managing Traumatic Rib Injuries: A Review of the Literature.

Timely repair is essential to maximizing outcomes in patients with traumatic rib injuries, whether in the presence or absence of flail chest (FC) or existing as single or multiple rib fractures (MRF), due to its high morbidity and mortality rate. This review focuses primarily on the plating system as an effective surgical approach to stabilizing these injuries. Literature was surveyed using the Google Scholar, PLOS One, and PubMed search engines between August 2021 and April 2022. A total of 34 articles were included herein, and primary and secondary outcomes were assessed. The primary outcomes of interest were intensive care unit length-of-stay (ICU LOS), hospital length-of-stay (HLOS), ventilatory requirements, and mortality rate. The secondary outcomes of interest were postoperative pain level and postoperative complications. The majority of the studies included herein reported lower ICU LOS, HLOS, and ventilation requirements in surgical patients when compared to conservatively managed patients. However, variables such as the presence or absence of FC also impacted outcomes in certain studies. Mortality rate and postoperative pain were largely underreported in the selected studies, but limited data from these studies suggest that these outcomes tend to be lower in surgical patients compared to those treated conservatively. When present, postoperative complications were often less severe amongst surgical patients compared to conservatively managed patients. Results further suggest that surgical repair is associated with lower pain severity as early as 72 hours postop. Likewise, findings suggest that early rib fracture stabilization is superior to late stabilization and often yields a sooner return to a baseline health status. Few studies report little to no statistical difference in primary and secondary outcomes between operative and conservative treatment. However, there is greater evidence that suggests the contrary, with better short-term and potential for better long-term outcomes in patients who undergo rib fixation.

Bariatric Surgery With Roux-En-Y Gastric Bypass or Sleeve Gastrectomy for Treatment of Obesity and Comorbidities: Current Evidence and Practice.

BACKGROUND: With the growing prevalence of obesity in the global population, alternative measures for weight loss and treatment of comorbidities must be considered due to the increasing difficulty of conservative management alone. Here we discuss the benefits of bariatric surgery on weight loss as well comorbidities that are present in a majority of obese patients.  Methods: In this review, we discuss the current practice and evidence of bariatric surgery as it pertains to weight loss and the beneficial effect on comorbidities commonly present in obesity. RESULTS:  Our review found that bariatric surgery with either the roux-en-y gastric bypass or laparoscopic sleeve gastrectomy can result in weight loss of up to 80% of excess weight. We also found that bariatric surgery has a profound effect on multiple comorbidities such as type 2 diabetes mellitus, hypertension, and hyperlipidemia through remission of the disease. CONCLUSION:  Bariatric surgery serves as an efficacious alternative for treatment of obesity and comorbidities.

High-Throughput Screening to Examine the Dynamic of Stay-Green by an Imaging System.

The development of RGB (red, green, blue) sensors has opened the way for plant phenotyping. This is relevant because plant phenotyping allows us to visualize the product of the interaction between the plant ontogeny, anatomy, physiology, and biochemistry. Better yet, this can be achieved at any stage of plant development, i.e., from seedling to maturity. Here, we describe the use of phenotyping, based on the stay-green trait, of common bean (Phaseolus vulgaris L.) plant, as a model, stressed by water deficit, to elucidate the result of that interaction. Description is based on interpretation of RGB digital images acquired using a phenomic platform and a specific software. These images allow us to obtain a data group related to the color parameters that quantify the changes and alterations in each plant growth and development.

Phenotypic, Anatomical, and Diel Variation in Sugar Concentration Linked to Cell Wall Invertases in Common Bean Pod Racemes under Water Restriction.

The common bean (Phaseolus vulgaris L.) pod wall is essential for seed formation and to protect seeds. To address the effect of water restriction on sugar metabolism in fruits differing in sink strength under light-dark cycles, we used plants of cv. OTI at 100% field capacity (FC) and at 50% FC over 10 days at the beginning of pod filling. Water restriction intensified the symptoms of leaf senescence. However, pods maintained a green color for several days longer than leaves did. In addition, the functionality of pods of the same raceme was anatomically demonstrated, and no differences were observed between water regimes. The glucose and starch concentrations were lower than those of sucrose, independent of pod wall size. Remarkably, the fructose concentration decreased only under water restriction. The cell wall invertase activity was twofold higher in the walls of small pods than in those of large ones in both water regimes; similar differences were not evident for cytosolic or vacuolar invertase. Using bioinformatics tools, six sequences of invertase genes were identified in the P. vulgaris genome. The PvINVCW4 protein sequence contains substitutions for conserved residues in the sucrose-binding site, while qPCR showed that transcript levels were induced in the walls of small pods under stress. The findings support a promising strategy for addressing sink strength under water restriction.

Percutaneous Endoscopic Gastrostomy Misplacement in the Transverse Colon of a Neurocognitively Compromised Patient.

Percutaneous endoscopic gastrostomy (PEG) tube placement is a widespread method of delivering sustained nutrition to individuals requiring long-term support. Multiple techniques exist to achieve this, and adverse events can arise if not done properly including but not limited to pneumoperitoneum and bowel perforation. Safeguard tactics exist to prevent these complications but they are not always successful. Herein, we explore a case of PEG tube misplacement through the transverse colon.  A 69-year-old male with a history of advanced dementia, cerebrovascular accident (CVA), and seizure disorder presented for a replacement of his malfunctioning PEG tube at a different site. On postoperative day one, the patient developed abdominal pain and shortness of breath. His subsequent imaging workup revealed pneumoperitoneum, and the patient ultimately underwent an exploratory laparotomy to repair the damage, washout his abdomen, and reinsert the PEG tube. Postoperatively, the patient had a lengthy hospital stay, which was complicated and prolonged by sepsis and mechanical ventilation.  The PEG tube placement procedure is not without its difficulties in all stages, pre- intra- and post-operatively, especially in patients with neurocognitive compromise, therefore, it is important to continue exploring methods to optimize the operation.

Starch accumulation in bean fruit pericarp is mediated by the differentiation of chloroplasts into amyloplasts.

The sucrose supply to bean fruits remains almost constant during seed development, and the early stages of this process are characterized by a significant amount of starch and soluble sugars (glucose, fructose and sucrose) accumulated in the pericarp. Bean fruits are photosynthetically active; however, our results indicated that starch synthesis in the pericarp was largely dependent on the photosynthetic activity of the leaves. The photosynthetic activity and the amount of the Rubisco large subunit were gradually reduced in the fruit pericarp, and a large increase in the amount of the ADP-glucose pyrophosphorylase small subunit (AGPase SS) was observed. These changes suggested differentiation of chloroplasts into amyloplasts. Pericarp chloroplasts imported glucose 1-P to support starch synthesis, and their differentiation into amyloplasts allowed the surplus sucrose to be used in the synthesis of starch, which was later degraded to meet the needs of fast-growing seeds. Starch stored in the bean fruit pericarp was not degraded in response to drought stress, but it was rapidly used under severe nutrient restriction. Together, this work indicated that starch accumulation in the pericarp of bean fruits is important to adjust the needs of developing seeds to the amount of sucrose that is provided to fruits.

Sternotomy Approach to the Anterior Cervicothoracic Spine.

The anterior cervicothoracic spine is a challenging region to approach given the various vascular, osseous, nervous, and articular structures, which prevent adequate exposure. This region is susceptible to lesions ranging from tumors, degenerative disease, infectious processes, and traumatic fractures. Our objective was to critically evaluate the sternotomy approach in spine surgery to give the technical implications of its usage. The safety and efficacy of the transsternal approach are discussed as well as the advantages, disadvantages, indications, and contraindications. The transsternal approach is the most direct access to pathologies in the upper anterior cervicothoracic spine and enables the spine surgeon to gain direct exposure to the cervicothoracic junction for ideal visualization. Anatomical considerations must be kept in mind while performing a sternotomy to prevent complications such as denervation or bleeding. This technique is useful for the armamentarium of spinal surgeons.

Neuroprotective strategies of cerebrolysin for the treatment of infants with neonatal hypoxic-ischemic encephalopathy.

BACKGROUND: Perinatal asphyxia (PA) is a devastating neonatal condition characterized by a lack of oxygen supporting the organ systems. PA can lead to hypoxic-ischemic encephalopathy (HIE), a brain dysfunction due to oxygen deprivation with a complex neurological sequela. The pathophysiology of HIE and PA is not entirely understood, with therapeutic hypothermia being the standard treatment with only limited value. However, alternative neuroprotective therapies can be a potential treatment modality. METHODS: In this review, we will characterize the biochemical mechanisms of PA and HIE, while also giving insight into cerebrolysin, a neuroprotective treatment used for HIE and PA. RESULTS: We found that cerebrolysin has up to 6-month treatment window post-ischemic insult. Cerebrolysin injections of 0.1 ml/kg of body weight twice per week were found to provide gross motor and speech deficit improvement. CONCLUSION: Our literature search emphasizes the positive effects of cerebrolysin for general improvement outcomes. Nevertheless, biomarker establishment is warranted to improve patient outcomes.

The Appendix: A Rare Case of an Appendiceal Collision Tumor.

Appendicitis is a common cause of right lower quadrant pain. However, appropriate diagnostic evaluation and a high clinical suspicion can reveal alternative etiologies that are not so commonly encountered. In this report, we present a rare case of an appendiceal collision tumor involving two distinct neoplasms as the source of the patient's pain and describe how thoughtful clinical maneuvering led to its diagnosis and treatment.

Physcomitrium patens Infection by Colletotrichum gloeosporioides: Understanding the Fungal-Bryophyte Interaction by Microscopy, Phenomics and RNA Sequencing.

Anthracnose caused by the hemibiotroph fungus Colletotrichum gloeosporioides is a devastating plant disease with an extensive impact on plant productivity. The process of colonization and disease progression of C. gloeosporioides has been studied in a number of angiosperm crops. To better understand the evolution of the plant response to pathogens, the study of this complex interaction has been extended to bryophytes. The model moss Physcomitrium patens Hedw. B&S (former Physcomitrella patens) is sensitive to known bacterial and fungal phytopathogens, including C. gloeosporioides, which cause infection and cell death. P. patens responses to these microorganisms resemble that of the angiosperms. However, the molecular events during the interaction of P. patens and C. gloeosporioides have not been explored. In this work, we present a comprehensive approach using microscopy, phenomics and RNA-seq analysis to explore the defense response of P. patens to C. gloeosporioides. Microscopy analysis showed that appressoria are already formed at 24 h after inoculation (hai) and tissue colonization and cell death occur at 24 hai and is massive at 48 hai. Consequently, the phenomics analysis showed progressing browning of moss tissues and impaired photosynthesis from 24 to 48 hai. The transcriptomic analysis revealed that more than 1200 P. patens genes were differentially expressed in response to Colletotrichum infection. The analysis of differentially expressed gene function showed that the C. gloeosporioides infection led to a transcription reprogramming in P. patens that upregulated the genes related to pathogen recognition, secondary metabolism, cell wall reinforcement and regulation of gene expression. In accordance with the observed phenomics results, some photosynthesis and chloroplast-related genes were repressed, indicating that, under attack, P. patens changes its transcription from primary metabolism to defend itself from the pathogen.

Paracoccygeal Transsacral Approach: A Rare Approach for Axial Lumbosacral Interbody Fusion.

Lumbosacral interbody fusion is a mainstay of surgical treatment for degenerative spinal pathologies causing chronic pain and functional impairment. However, the optimal technique for this procedure remains controversial. Well-established open approaches, including anterior lumbar interbody fusion (ALIF), posterior lumbar interbody fusion (PLIF), and transforaminal lumbar interbody fusion (TLIF), have historically been the standard of practice. A recent paradigm shift in spinal surgery has led to the investigation of minimally invasive approaches to mitigate tissue damage without compromising outcomes. This extensive review aims to examine current clinical and biomechanical evidence on the paracoccygeal transsacral approach to an axial lumbosacral interbody fusion. Since this technique was first described in 2004, accumulating evidence suggests it results in high fusion rates, consistent improvements in pain and function, reduced perioperative morbidity, and low rates of complication. Although early clinical outcomes have been promising, there is a paucity of comparative data investigating outcomes of the paracoccygeal transsacral approach to traditional alternatives and other minimally invasive techniques. Here, we summarize current evidence and discuss pertinent topics for the spinal surgeon considering this novel approach, including indications, advantages, relevant anatomy, contraindications, and technical considerations.

Interaction among species, time-of-day, and soil water potential on biochemical and physiological characteristics of cladodes of Opuntia.

The physiology and biochemistry of young Opuntia spp. cladodes relate with their Crassulacean acid metabolism, which extends over the day-night cycle in four phases, is species-dependent and is affected by water availability. This study aimed to assess the interaction among species, time-of-day, and the soil water potential (ΨW) on biochemical and physiological characteristics of cladodes of Opuntia species. Three-week-old cladodes were harvested at 7:00 a.m. and 3:00 p.m. from plants with or without irrigation for 30 d (-0.17 and -5.72 MPa soil ΨW), from O. albicarpa, O. ficus-indica, O. hyptiacantha, O. megacantha, and O. streptacantha. The experimental design was a factorial 5 x 2 x 2 (species, sampling time and soil ΨW). The experimental unit was one cladode per plant, and six repetitions were evaluated. Total acids, glucose, fructose, sucrose, starch, total phenolics, free amino acids, and soluble proteins concentrations were evaluated, as well as acid invertase and neutral invertase activities. The interaction among species x soil ΨW and species x time of the day was significant (P ≤ 0.05) in all variables evaluated. An exception was the species x soil ΨW on starch concentration (P = 0.1827). The biochemical and physiological characteristics of Opuntia cladodes were modified by the time of the day and soil ΨW interaction, but most of the characteristics were positively or inversely affected depending on the species, frequently displaying a descending trend following O. streptacantha, O. hyptiacantha, O. megacantha, O. albicarpa and O. ficus-indica. The total acids, glucose, fructose, starch, soluble proteins, and free amino acids concentrations revealed that domestication significantly modifies C and N metabolism in Opuntia.

Prevalence of sports-related spinal injury stratified by competition level and return to play guidelines.

Spinal injury is among the most severe and feared injuries an athlete may face. We present an up-to-date review of the recent literature, stratifying recommendations based on injury location (cervical, thoracic, and lumbar spine) and type, as well as, the level of competitive play (high school, collegiate, professional). A literature search was completed to identify all publications reporting return to play guidelines for athletic injuries or injury-related surgery irrespective of the study design. Publication dates were not restricted by year. Search terms used included "return to play" and "spinal injury" on National Library of Medicine (PubMed) and Google Scholar. Selection criteria for literature included axial spine injury guidelines for athletic participation post-injury or post-surgery. Literature found from the search criteria was sorted based on level of competition and location of axial spine injury involved. It was found that professional athletes are more likely to suffer severe spinal injuries, require surgery, and necessitate a longer return to play (RTP), with high school and college athletes usually returning to play within days or weeks. Injuries occur mainly within contact sports and concordance exists between initial and subsequent spinal injuries. Adequate rest, rehabilitation, and protective equipment alongside the education of athletes and coaches are recommended. In conclusion, a multidisciplinary approach to patient management is required with consideration for the emotional, social, and perhaps financial impact that spinal injury may have upon the athlete. Consensus from the literature states that in order for an athlete to safely return to play, that athlete should not be actively suffering from pain, should have a full range of motion, and complete return of their strength in the absence of neurological deficit.

A Review of Mechanisms on the Beneficial Effect of Exercise on Atherosclerosis.

Cardiovascular disease has affected a large percentage of the world, and as a result, we have had major advancements in pharmacological and procedural intervention of this disease. With the increased burden of rising healthcare costs, alternative treatment with exercise has shown to be much more cost effective and just as beneficial to patients compared to pharmacological and procedural treatment. We highlight some of the major mechanisms behind the beneficial effect of exercise on atherosclerosis and hope to encourage patients and providers to attempt to adopt this form of treatment that has not only shown to be beneficial to heart disease, but diseases such as diabetes and obesity as well.

Association between Burnout Syndrome and medical training by specialty in first-year residents / Síndrome de burnout en residentes de primer año: asociación por especialidad

Abstract Introduction Burnout syndrome (BOS) comprises emotional exhaustion, depersonalization, and reduced personal accomplishment in those affected. Instruments such as the Maslach Burnout Inventory (MBI) can help to identify those affected. Physicians in training have been described as an at-risk group for this syndrome. Objective Describe the association between BOS and medical training by specialty in first-year residents. Method This is a cross-sectional analytical study of specialty residents at the Hospital Civil de Guadalajara. Sociodemographic data were obtained and the MBI was administered to identify BOS. Samples were compared, and a comparative analysis performed to identify factors associated with BOS. Results Eighty-eight residents were included, with 21.6% (n = 19) presenting BOS, 53.4% displaying emotional exhaustion (n = 47), 53.7% showing depersonalization (n = 47), and 39.8% reduced personal accomplishment (n = 35). Presenting BOS was not associated with sociodemographic characteristics or type of specialty. Work hours (ro = .229, p = .032), and a higher number of on-call hours/week (ro = .34, p = .001) were associated with higher BOS. Discussion and conclusion The prevalence of BOS was lower than expected. Over half scored for emotional exhaustion and depersonalization, which could be explained by a self-reporting bias. There was no association between the group/type of specialty and BOS. This study creates new knowledge that works as an institutional situational diagnosis, helps to determine the scope of the problem, and encourages to consider the contributing factors to its origin and maintenance.

Resumen Introducción El síndrome de burnout (SBO) comprende el agotamiento emocional, la despersonalización y la reducción de la realización personal en aquellos a quienes afecta. Instrumentos como el Maslach Burnout Inventory (MBI) pueden ayudar a identificar a los afectados. Los médicos en formación se han descrito como un grupo de riesgo para presentar este síndrome. Objetivo Describir la asociación entre el síndrome de burnout y la formación médica por especialidad en residentes de primer año. Método Se trata de un estudio analítico transversal de residentes de especialidad del Hospital Civil de Guadalajara. Se obtuvieron datos sociodemográficos y se administró el MBI para identificar SBO. Se compararon las muestras y se realizó un análisis comparativo para identificar los factores asociados con SBO. Resultados Se incluyeron 88 residentes, con 21.6% (n = 19) presentando SBO; 53.4% mostrando agotamiento emocional (n = 47); 53.7% (n = 47) mostrando despersonalización; y 39.8% (n = 35) reducción de realización personal. La presentación de SBO no se asoció a características sociodemográficas ni al tipo de especialidad. Las horas de trabajo (ro = .229, p = .032) y un mayor número de horas de guardia/semana (ro = .34, p = .001) se asociaron con una mayor BOS. Discusión y conclusión La prevalencia de SBO fue menor de lo esperado. Más de la mitad puntuó por agotamiento emocional y despersonalización, lo que podría explicarse por un sesgo en la autoevaluación. No hubo asociación entre el grupo/tipo de especialidad y SBO. Este estudio genera nuevos conocimientos que funcionan como un diagnóstico situacional institucional, ayuda a determinar el alcance del problema y alienta a considerar los factores que contribuyen a su origen y mantenimiento.

Total Posterior Spinal Arthroplasty Systems for Dynamic Stability.

Degenerative disease of the lumbar spine commonly develops with age and can cause debilitating pain or neurologic deficits. When minimally invasive treatments and pain management interventions fail to provide relief, the traditional treatment has consisted of decompression surgery followed by the possible need for lumbar fusion. A mechanical implant device, known as a Total Posterior Spine (TOPS) System, has been introduced as a potential dynamic alternative to fusion surgery following decompression. The device is a dynamic posterior arthroplasty via pedicle screw insertion that maintains mobility, flexibility, and range of motion by providing multiaxial, three-column stabilization. While currently approved for use in Europe, the device is undergoing clinical trials in the United States to determine efficacy and potential complications. This paper provides a comprehensive narrative review of this technique's mechanism, early clinical outcomes, and considerations for patient selection. A review of the literature identified both positive results and adverse effects. While TOPS' use shows excellent potential, additional prospective trials are needed to determine this system's long-term complications.

Isolation and characterization of psychrophilic and psychrotolerant plant-growth promoting microorganisms from a high-altitude volcano crater in Mexico.

Extreme ecosystems are a possible source of new interesting microorganisms, in this study the isolation of psychrophilic and psychrotolerant plant growth promoting microorganisms was pursued in a cold habitat, with the aim of finding novel microbes that can protect crops from cold. Eight yeast and four bacterial strains were isolated from rhizospheric soil collected from the Xinantécatl volcano in Mexico, and characterized for plant growth promoting properties. Most of the yeasts produced indole acetic acid and hydrolytic enzymes (cellulases, xilanases and chitinases), but none of them produced siderophores, in contrast to their bacterial counterparts. Inorganic phosphate solubilization was detected for all the bacterial strains and for two yeast strains. Yeast and bacterial strains may inhibit growth of various pathogenic fungi, propounding a role in biological control. Microorganisms were identified up to genera level, by applying ribotyping techniques and phylogenetic analysis. Bacterial strains belonged to the genus Pseudomonas, whereas yeast strains consisted of Rhodotorula sp. (4), Mrakia sp. (3) and Naganishia sp. (1). New species belonging to the aforementioned genera seem to have been isolated from both bacteria and yeasts. Germination promoting activity on Solanum lycopersicum seeds was detected for all strains compared to a control, whereas tomato plantlets, grown at 15 °C in the presence of some of the strains, performed better than the non-inoculated plantlets. This study offers the possibility of using these strains as an additive to improve culture conditions of S. lycopersicum in a more environmentally compatible way. This is the first study to propose psychrophilic/psychrotolerant yeasts, as plant growth promoting microbes.

A gain-of-function mutation of plastidic invertase alters nuclear gene expression with sucrose treatment partially via GENOMES UNCOUPLED1-mediated signaling.

Plastid gene expression (PGE) is one of the signals that regulate the expression of photosynthesis-associated nuclear genes (PhANGs) via GENOMES UNCOUPLED1 (GUN1)-dependent retrograde signaling. We recently isolated Arabidopsis sugar-inducible cotyledon yellow-192 (sicy-192), a gain-of-function mutant of plastidic invertase, and showed that following the treatment of this mutant with sucrose, the expression of PhANGs as well as PGE decreased, suggesting that the sicy-192 mutation activates a PGE-evoked and GUN1-mediated retrograde pathway. To clarify the relationship between the sicy-192 mutation, PGE, and GUN1-mediated pathway, plastid and nuclear gene expression in a double mutant of sicy-192 and gun1-101, a null mutant of GUN1 was studied. Plastid-encoded RNA polymerase (PEP)-dependent PGE was markedly suppressed in the sicy-192 mutant by the sucrose treatment, but the suppression as well as cotyledon yellow phenotype was not mitigated by GUN1 disruption. Microarray analysis revealed that the altered expression of nuclear genes such as PhANG in the sucrose-treated sicy-192 mutant was largely dependent on GUN1. The present findings demonstrated that the sicy-192 mutation alters nuclear gene expression with sucrose treatment via GUN1, which is possibly followed by inhibiting PEP-dependent PGE, providing a new insight into the role of plastid sugar metabolism in nuclear gene expression.