Transcriptome Analysis of WIPK/SIPK-Suppressed Plants Reveals Induction by Wounding of Disease Resistance-Related Genes Prior to the Accumulation of Salicylic Acid

Salicylic acid (SA) plays a key role in plant resistance to pathogens. Accumulation of SA is induced by wounding in tobacco plants in which the expression of WIPK and SIPK, two mitogen-activated protein kinases, is suppressed. Here, the mechanisms underlying the abnormal accumulation of SA in WIPK/SIPK-suppressed plants have been characterized. SA accumulation started around 12 h after wounding and was inhibited by cycloheximide (CHX), a protein synthesis inhibitor. SA accumulation, however, was enhanced several fold when leaf discs were transferred onto CHX after floating on water for >= 6 h. Temporal and spatial analyses of wound-induced and CHX-enhanced SA accumulation suggested that wounding induces activators for SA accumulation followed by the generation of repressors, and late CHX treatment inhibits the production of repressors more efficiently than that of activators. Microarray analysis revealed that the expression of many disease resistance-related genes, including N, a Resistance (R) gene for Tobacco mosaic virus and R gene-like genes, was up-regulated in wounded WIPK/SIPK-suppressed plants. Expression of the N gene and R gene-like genes peaked earlier than that of most other genes as well as SA accumulation, and was mainly induced in those parts of leaf discs where SA was highly accumulated. Moreover, wound-induced SA accumulation was decreased by the treatments which compromise the function of R proteins. These results indicate that signaling leading to the expression of disease resistance-related genes is activated by wounding in WIPK/SIPK-suppressed plants, and induction of R gene and R gene-like genes might lead to the biosynthesis of SA.ArticlePLANT AND CELL PHYSIOLOGY. 54(6):1005-1015 (2013)journal articl

Characteristic expression of twelve rice PR1 family genes in response to pathogen infection, wounding, and defense-related signal compounds (121/180)

Pathogenesis-related (PR) proteins have been used as markers of plant defense responses, and are classified into 17 families. However, precise information on the majority members in specific PR families is still limited. We were interested in the individual characteristics of rice PR1 family genes, and selected 12 putatively active genes using rice genome databases for expressed genes. All were upregulated upon compatible and/or incompatible rice-blast fungus interactions; three were upregulated in the early infection period and four in the late infection period. Upon compatible rice–bacterial blight interaction, four genes were upregulated, six were not affected, and one was downregulated. These results are in striking contrast to those among 22 ArabidopsisPR1 genes where only one gene was pathogen-inducible. The responses of individual genes to salicylic acid, jasmonic acid, and ethylene induced defense signaling pathways in rice are likely to be different from those in dicot plants. Transcript levels in healthy leaves, roots, and flowers varied according to each gene. Analysis of the partially overlapping expression patterns of rice PR1 genes in healthy tissues and in response to pathogens and other stresses would be useful to understand their possible functions and for use as characteristic markers for defense-related studies in rice

Jasmonate-dependent plant defense restricts thrips performance and preference

<p>Abstract</p> <p>Background</p> <p>The western flower thrips (<it>Frankliniella occidentalis </it>[Pergande]) is one of the most important insect herbivores of cultivated plants. However, no pesticide provides complete control of this species, and insecticide resistance has emerged around the world. We previously reported the important role of jasmonate (JA) in the plant's immediate response to thrips feeding by using an <it>Arabidopsis </it>leaf disc system. In this study, as the first step toward practical use of JA in thrips control, we analyzed the effect of JA-regulated <it>Arabidopsis </it>defense at the whole plant level on thrips behavior and life cycle at the population level over an extended period. We also studied the effectiveness of JA-regulated plant defense on thrips damage in Chinese cabbage (<it>Brassica rapa </it>subsp. <it>pekinensis</it>).</p> <p>Results</p> <p>Thrips oviposited more on <it>Arabidopsis </it>JA-insensitive <it>coi1-1 </it>mutants than on WT plants, and the population density of the following thrips generation increased on <it>coi1-1 </it>mutants. Moreover, thrips preferred <it>coi1-1 </it>mutants more than WT plants. Application of JA to WT plants before thrips attack decreased the thrips population. To analyze these important functions of JA in a brassica crop plant, we analyzed the expression of marker genes for JA response in <it>B. rapa</it>. Thrips feeding induced expression of these marker genes and significantly increased the JA content in <it>B. rapa</it>. Application of JA to <it>B. rapa </it>enhanced plant resistance to thrips, restricted oviposition, and reduced the population density of the following generation.</p> <p>Conclusion</p> <p>Our results indicate that the JA-regulated plant defense restricts thrips performance and preference, and plays an important role in the resistance of <it>Arabidopsis </it>and <it>B. rapa </it>to thrips damage.</p

Impact of neoadjuvant intensity-modulated radiation therapy on borderline resectable pancreatic cancer with arterial abutment; a prospective, open-label, phase II study in a single institution

BACKGROUND: Borderline resectable pancreatic cancer (BRPC) is a category of pancreatic cancer that is anatomically widely spread, and curative resection is uncommon with upfront surgery. Intensity-modulated radiation therapy (IMRT) is a form of radiation therapy that delivers precise radiation to a tumor while minimizing the dose to surrounding normal tissues. Here, we conducted a phase 2 study to estimate the curability and efficacy of neoadjuvant chemoradiotherapy using IMRT (NACIMRT) for patients with BRPC with arterial abutment (BRPC-A). METHODS: A total of 49 BRPC-A patients were enrolled in this study and were treated at our hospital according to the study protocol between June 2013 and March 2021. The primary endpoint was microscopically margin-negative resection (R0) rates and we subsequently analyzed safety, histological effect of the treatment as well as survivals among patients with NACIMRT. RESULTS: Twenty-nine patients (59.2%) received pancreatectomy after NACIMRT. The R0 rate in resection patients was 93.1% and that in the whole cohort was 55.1%. No mortality was encountered. Local therapeutic effects as assessed by Evans classification showed good therapeutic effect (Grade 1, 3.4%; Grade 2a, 31.0%; Grade 2b, 48.3%; Grade 3, 3.4%; Grade 4, 3.4%). Median disease-free survival was 15.5 months. Median overall survival in the whole cohort was 35.1 months. The only independent prognostic pre-NACIMRT factor identified was serum carbohydrate antigen 19-9 (CA19-9) > 400 U/ml before NACIMRT. CONCLUSIONS: NACIMRT showed preferable outcome without significant operative morbidity for BRPC-A patients. NACIMRT contributes to good local tumor control, but a high initial serum CA19-9 implies poor prognosis even after neoadjuvant treatment. TRIAL REGISTRATION: UMIN-CTR Clinical Trial: https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000011776 Registration number: UMIN000010113. Date of first registration: 01/03/2013

Conversion to complete resection with mFOLFOX6 with bevacizumab or cetuximab based on K‐RAS status for unresectable colorectal liver metastasis (BECK study): Long‐term results of survival

[Background/Purpose]To investigate the long‐term outcome and entire treatment course of patients with technically unresectable CRLM who underwent conversion hepatectomy and to examine factors associated with conversion to hepatectomy. [Methods]Recurrence and survival data with long‐term follow‐up were analyzed in the cohort of a multi‐institutional phase II trial for technically unresectable colorectal liver metastases (the BECK study). [Results]A total of 22/12 patients with K‐RAS wild‐type/mutant tumors were treated with mFOLFOX6 + cetuximab/bevacizumab. The conversion R0/1 hepatectomy rate was significantly higher in left‐sided primary tumors than in right‐sided tumors (75.0% vs 30.0%, P = .022). The median follow‐up was 72.6 months. The 5‐year overall survival (OS) rate in the entire cohort was 48.1%. In patients who underwent R0/1 hepatectomy (n = 21), the 5‐year RFS rate and OS rate were 19.1% and 66.3%, respectively. At the final follow‐up, seven patients had no evidence of disease, five were alive with disease, and 20 had died from their original cancer. All 16 patients who achieved 5‐year survival underwent conversion hepatectomy, and 11 of them underwent further resection for other recurrences (median: 2, range: 1‐4). [Conclusions]Conversion hepatectomy achieved a similar long‐term survival to the results of previous studies in initially resectable patients, although many of them experienced several post‐hepatectomy recurrences. Left‐sided primary was found to be the predictor for conversion hepatectomy

The role of microenvironment and immunity in drug response in leukemia

Leukemia is a cancer of the white blood cells, with over 54,000 new cases per year diagnosed worldwide and a 5-year survival rate below 60%. This highlights a need for research into the mechanisms behind its etiology and causes of therapy failure. The bone marrow microenvironment, in which adult stem cells are maintained in healthy individuals, has been implicated as a source of chemoresistance and disease relapse. Here the various ways that the microenvironment can contribute to the resistance and persistence of leukemia are discussed. The targeting of the microenvironment by leukemia cells to create an environment more suitable for cancer progression is described. The role of soluble factors, drug transporters, microvesicles, as well as the importance of direct cell–cell contact, in addition to the effects of inflammation and immune surveillance in microenvironment-mediated drug resistance are discussed. An overview of the clinical potential of translating research findings to patients is also provided. Understanding of and further research into the role of the bone marrow microenvironment in leukemia progression and relapse are crucial towards developing more effective treatments and reduction in patient morbidity

Lutein, a Natural Carotenoid, Induces α-1,3-Glucan Accumulation on the Cell Wall Surface of Fungal Plant Pathogens

α-1,3-Glucan, a component of the fungal cell wall, is a refractory polysaccharide for most plants. Previously, we showed that various fungal plant pathogens masked their cell wall surfaces with α-1,3-glucan to evade plant immunity. This surface accumulation of α-1,3-glucan was infection specific, suggesting that plant factors might induce its production in fungi. Through immunofluorescence observations of fungal cell walls, we found that carrot (Daucus carota) extract induced the accumulation of α-1,3-glucan on germlings in Colletotrichum fioriniae, a polyphagous fungal pathogen that causes anthracnose disease in various dicot plants. Bioassay-guided fractionation of carrot leaf extract successfully identified two active substances that caused α-1,3-glucan accumulation in this fungus: lutein, a carotenoid widely distributed in plants, and stigmasterol, a plant-specific membrane component. Lutein, which had a greater effect on C. fioriniae, also induced α-1,3-glucan accumulation in other Colletotrichum species and in the phylogenetically distant rice pathogen Cochliobolus miyabeanus, but not in the rice pathogen Magnaporthe oryzae belonging to the same phylogenetic subclass as Colletotrichum. Our results suggested that fungal plant pathogens reorganize their cell wall components in response to specific plant-derived compounds, which these pathogens may encounter during infection

α-Ionone, an Apocarotenoid, Induces Plant Resistance to Western Flower Thrips, Frankliniella occidentalis, Independently of Jasmonic Acid

Apocarotenoids, such as &beta;-cyclocitral, &alpha;-ionone, &beta;-ionone, and loliolide, are derived from carotenes via chemical or enzymatic processes. Recent studies revealed that &beta;-cyclocitral and loliolide play an important role in various aspects of plant physiology, such as stress responses, plant growth, and herbivore resistance. However, information on the physiological role of &alpha;-ionone is limited. We herein investigated the effects of &alpha;-ionone on plant protection against herbivore attacks. The pretreatment of whole tomato (Solanum lycopersicum) plants with &alpha;-ionone vapor decreased the survival rate of western flower thrips (Frankliniella occidentalis) without exhibiting insecticidal activity. Exogenous &alpha;-ionone enhanced the expression of defense-related genes, such as basic &beta;-1,3-glucanase and basic chitinase genes, in tomato leaves, but not that of jasmonic acid (JA)- or loliolide-responsive genes. The pretreatment with &alpha;-ionone markedly decreased egg deposition by western flower thrips in the JA-insensitive Arabidopsis (Arabidopsis thaliana) mutant coi1-1. We also found that common cutworm (Spodoptera litura) larvae fed on &alpha;-ionone-treated tomato plants exhibited a reduction in weight. These results suggest that &alpha;-ionone induces plant resistance to western flower thrips through a different mode of action from that of JA and loliolide