A Novel Mutation in the XLRS1 Gene in a Korean Family with X-linked Retinoschisis

Purpose: To report a novel missense mutation in the XLRS1 gene in a Korean family with X-linked retinoschisis. Methods: Observation case report of a family with a proband with X-linked retinoschisis underwent complete ophthalmologic examination. Genomic DNA was excluded from the family's blood and all exons of the XLRS1 gene were amplified by polymerase chain reaction and analyzed using a direct sequencing method. Results: A novel Leu103Phe missense mutation was identified. Conclusions: A novel Leu103Phe mutation is an additional missense mutation which is responsible for the pathogenesis of X-linked retinoschisis.ope

Chiral symmetry and taste symmetry from the eigenvalue spectrum of staggered Dirac operators

We investigate general properties of the eigenvalue spectrum for improved staggered quarks. We introduce a new chirality operator $[\gamma_5 \otimes 1]$ and a new shift operator $[1 \otimes \xi_5]$, which respect the same recursion relation as the $\gamma_5$ operator in the continuum. Then we show that matrix elements of the chirality operator sandwiched between two eigenstates of the staggered Dirac operator are related to those of the shift operator by the Ward identity of the conserved $U(1)_A$ symmetry of staggered fermion actions. We perform a numerical study in quenched QCD using HYP staggered quarks to demonstrate the Ward identity. We introduce a new concept of leakage patterns which collectively represent the matrix elements of the chirality operator and the shift operator sandwiched between two eigenstates of the staggered Dirac operator. The leakage pattern provides a new method to identify zero modes and non-zero modes in the Dirac eigenvalue spectrum. This method is as robust as the spectral flow method but requires much less computing power. Analysis using a machine learning technique confirms that the leakage pattern is universal, since the staggered Dirac eigenmodes on normal gauge configurations respect it. In addition, the leakage pattern can be used to determine a ratio of renormalization factors as a by-product. We conclude that it might be possible and realistic to measure the topological charge $Q$ using the Atiya-Singer index theorem and the leakage pattern of the chirality operator in the staggered fermion formalism.Comment: 27 pages, 78 figures, 10 tables, references updated, more explanation adde

Convergent Evolution of Pathogen Effectors toward Reactive Oxygen Species Signaling Networks in Plants

Microbial pathogens have evolved protein effectors to promote virulence and cause disease in host plants. Pathogen effectors delivered into plant cells suppress plant immune responses and modulate host metabolism to support the infection processes of pathogens. Reactive oxygen species (ROS) act as cellular signaling molecules to trigger plant immune responses, such as pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity. In this review, we discuss recent insights into the molecular functions of pathogen effectors that target multiple steps in the ROS signaling pathway in plants. The perception of PAMPs by pattern recognition receptors leads to the rapid and strong production of ROS through activation of NADPH oxidase Respiratory Burst Oxidase Homologs (RBOHs) as well as peroxidases. Specific pathogen effectors directly or indirectly interact with plant nucleotide-binding leucine-rich repeat receptors to induce ROS production and the hypersensitive response in plant cells. By contrast, virulent pathogens possess effectors capable of suppressing plant ROS bursts in different ways during infection. PAMP-triggered ROS bursts are suppressed by pathogen effectors that target mitogen-activated protein kinase cascades. Moreover, pathogen effectors target vesicle trafficking or metabolic priming, leading to the suppression of ROS production. Secreted pathogen effectors block the metabolic coenzyme NADP-malic enzyme, inhibiting the transfer of electrons to the NADPH oxidases (RBOHs) responsible for ROS generation. Collectively, pathogen effectors may have evolved to converge on a common host protein network to suppress the common plant immune system, including the ROS burst and cell death response in plants

Understanding the Responses of Rice to Environmental Stress Using Proteomics

Diverse abiotic and biotic stresses have marked effects on plant growth and productivity. To combat such stresses, plants have evolved complex but not well understood responses. Common effects upon perception of environmental stress are differential expression of the plant proteome and the synthesis of novel regulatory proteins for protection from and acclimation to stress conditions. Plants respond differently in terms of activation of stress-responsive signaling pathways depending upon the type and nature of the stresses to which they are exposed. Progress in proteomics and systems biology approaches has made it possible to identify the novel proteins and their interactions that function in abiotic stress responses. This will enable elucidation of the functions of individual proteins and their roles in signaling networks. Proteomic analysis of the responses to various stress conditions is performed most commonly using 2D gel electrophoresis and high-throughput identification by LC-MS/MS. Because of recent developments in proteomics techniques, numerous proteomics studies of rice under abiotic stress conditions have been performed. In this review, proteomics studies addressing rice responses to the major environmental stressesincluding cold, heat, drought, salt, heavy metals, minerals, UV radiation, and ozone are discussed. Unique or common protein responses to these stress conditions are summarized and interpreted according to their possible physiological responses in each stress. Additionally, proteomics studies on various plant systems under various abiotic stress conditions are compared to provide deeper understanding of specific and common proteome responses in rice and other plant systems, which will further contribute to the identification of abiotic stress tolerance factor at protein level. Functional analysis of stress-responsive proteins will provide new research objectives with the aim of achieving stable crop productivity in the face of the increasing abiotic stress conditions caused by global climate change

The NIN-Like Protein OsNLP2 Negatively Regulates Ferroptotic Cell Death and Immune Responses to Magnaporthe oryzae in Rice

Nodule inception (NIN)-like proteins (NLPs) have a central role in nitrate signaling to mediate plant growth and development. Here, we report that OsNLP2 negatively regulates ferroptotic cell death and immune responses in rice during Magnaporthe oryzae infection. OsNLP2 was localized to the plant cell nucleus, suggesting that it acts as a transcription factor. OsNLP2 expression was involved in susceptible disease development. ΔOsnlp2 knockout mutants exhibited reactive oxygen species (ROS) and iron-dependent ferroptotic hypersensitive response (HR) cell death in response to M. oryzae. Treatments with the iron chelator deferoxamine, lipid-ROS scavenger ferrostatin-1, actin polymerization inhibitor cytochalasin A, and NADPH oxidase inhibitor diphenyleneiodonium suppressed the accumulation of ROS and ferric ions, lipid peroxidation, and HR cell death, which ultimately led to successful M. oryzae colonization in ΔOsnlp2 mutants. The loss-of-function of OsNLP2 triggered the expression of defense-related genes including OsPBZ1, OsPIP-3A, OsWRKY104, and OsRbohB in ΔOsnlp2 mutants. ΔOsnlp2 mutants exhibited broad-spectrum, nonspecific resistance to diverse M. oryzae strains. These combined results suggest that OsNLP2 acts as a negative regulator of ferroptotic HR cell death and defense responses in rice, and may be a valuable gene source for molecular breeding of rice with broad-spectrum resistance to blast disease

Plant secretome: Unlocking secrets of the secreted proteins

International audiencePlant secretomics is a newly emerging area of the plant proteomics field. It basically describes the global study of secreted proteins into the extracellular space of plant cell or tissue at any given time and under certain conditions through various secretory mechanisms. A combination of biochemical, proteomics and bioinformatics approaches has been developed to isolate, identify and profile secreted proteins using complementary in vitro suspension-cultured cells and in planta systems. Developed inventories of secreted proteins under normal, biotic and abiotic conditions revealed several different types of novel secreted proteins, including the leaderless secretory proteins (LSPs). On average, LSPs can account for more than 50% of the total identified secretome, supporting, as in other eukaryotes, the existence of novel secretory mechanisms independent of the classical endoplasmic reticulum-Golgi secretory pathway, and suggesting that this non-classical mechanism of protein expression is, for as yet unknown reasons, more massively used than in other eukaryotic systems. Plants LSPs, which seem to be potentially involved in the defense/stress responses, might have dual (extracellular and/or intracellular) roles as most of them have established intracellular functions, yet presently unknown extracellular functions. Evidence is emerging on the role of glycosylation in the apical sorting and trafficking of secretory proteins. These initial secretome studies in plants have considerably advanced our understanding on secretion of different types of proteins and their underlying mechanisms, and opened a door for comparative analyses of plant secretomes with those of other organisms. In this first review on plant secretomics, we summarize and discuss the secretome definition, the applied approaches for unlocking secrets of the secreted proteins in the extracellular fluid, the possible functional significance and secretory mechanisms of LSPs, as well as glycosylation of secreted proteins and challenges involved ahead. Further improvements in existing and developing strategies and techniques will continue to drive forward plant secretomics research to building comprehensive and confident data sets of secreted proteins. This will lead to an increased understanding on how cells couple the concerted action of secreted protein networks to their internal and external environments