scholarly journals Clavibacter michiganensis subsp. michiganensis Vatr1 and Vatr2 Transcriptional Regulators Are Required for Virulence in Tomato

2014 ◽  
Vol 27 (10) ◽  
pp. 1035-1047 ◽  
Author(s):  
Alon Savidor ◽  
Laura Chalupowicz ◽  
Doron Teper ◽  
Karl-Heinz Gartemann ◽  
Rudolf Eichenlaub ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
High Titer ◽  
Acc Oxidase ◽  
Transcriptional Regulators ◽  
Wild Type ◽  
In Planta ◽  
Clavibacter Michiganensis ◽  
Clavibacter Michiganensis Subsp ◽  
Type C

The plant pathogen Clavibacter michiganensis subsp. michiganensis is a gram-positive bacterium responsible for wilt and canker disease of tomato. Although disease development is well characterized and diagnosed, molecular mechanisms of C. michiganensis subsp. michiganensis virulence are poorly understood. Here, we identified and characterized two C. michiganensis subsp. michiganensis transcriptional regulators, Vatr1 and Vatr2, that are involved in pathogenicity of C. michiganensis subsp. michiganensis. Vatr1 and Vatr2 belong to TetR and MocR families of transcriptional regulators, respectively. Mutations in their corresponding genes caused attenuated virulence, with the Δvatr2 mutant showing a more dramatic effect than Δvatr1. Although both mutants grew well in vitro and reached a high titer in planta, they caused reduced wilting and canker development in infected plants compared with the wild-type bacterium. They also led to a reduced expression of the ethylene-synthesizing tomato enzyme ACC-oxidase compared with wild-type C. michiganensis subsp. michiganensis and to reduced ethylene production in the plant. Transcriptomic analysis of wild-type C. michiganensis subsp. michiganensis and the two mutants under infection-mimicking conditions revealed that Vatr1 and Vatr2 regulate expression of virulence factors, membrane and secreted proteins, and signal-transducing proteins. A 70% overlap between the sets of genes positively regulated by Vatr1 and Vatr2 suggests that these transcriptional regulators are on the same molecular pathway responsible for C. michiganensis subsp. michiganensis virulence.

scholarly journals Deciphering the three-way interaction among Bacillus amyloliquefaciens MBI600, plants and phytopathogenic bacteria

2020 ◽  
Author(s):  
Αναστασία Δημοπούλου
Keyword(s):  
Ralstonia Solanacearum ◽  
Nicotiana Benthamiana ◽  
Bacillus Amyloliquefaciens ◽  
Erwinia Amylovora ◽  
In Planta ◽  
Clavibacter Michiganensis ◽  
Phytopathogenic Bacteria ◽  
Pseudomonas Spp ◽  
Clavibacter Michiganensis Subsp

Σκοπός αυτής της μελέτης ήταν να διασαφηνιστούν οι μηχανισμοί της τριπλής αλληλεπίδρασης μεταξύ του βιολογικού παράγοντα Β. amyloliquefaciens MBI600, φυτών και φυτοπαθογόνων βακτηρίων. Για τον σκοπό αυτό εφαρμόστηκε μια ολιστική προσέγγιση. Αρχικά, αξιολογήθηκε η βακτηριοκτόνος δράση του B. amyloliquefaciens ΜΒΙ600, in vitro και in planta, έναντι διαφόρων βακτηριακών παθογόνων. Στα in vitro πειράματα, το στέλεχος ΜΒΙ600 εμφάνισε αντιβακτηριακή δράση τόσο εναντίον Gram- όσο και Gram+ βακτηριακών ειδών. Μεταξύ των ειδών που ελέγχθηκαν, τα είδη Clavibacter michiganensis subsp. michiganensis, Ralstonia solanacearum και Xanthomonas spp. εμφάνισαν υψηλή ευαισθησία, το είδος Erwinia amylovora χαμηλή ευαισθησία ενώ το είδος Ε. chrysanthemi και όλα τα είδη του γένους Pseudomonas spp. δεν εμφάνισαν καθόλου ευαισθησία.Όσον αφορά τα in planta πειράματα, η εφαρμογή του εμπορικού σκευάσματος του ΜΒΙ600, Serifel, σε φύλλα τομάτας ανέστειλε τη μόλυνση από το φυτοπαθογόνο βακτήριο εδάφους R. solanacearum. Επίσης, ήταν ικανή να ελέγξει σημαντικά τα συμπτώματα της ασθένειας της βακτηριακής κηλίδωσης που προκαλείται από το είδος X. campestris pv. vesicatoria αλλά και της ασθένειας της βακτηριακής στιγμάτωσης της τομάτας που οφέιλεται στην μόλυνση από το είδος Ρ. syringae pv. tomato, ακόμη και αν η πυκνότητα του πληθυσμού δεν επηρεάστηκε σημαντικά. Επιπλέον, παρατηρήθηκε σημαντική μείωση τόσο των συμπτωμάτων της ασθένειας του βακτηριακού καψίματος της τομάτας όσο και της πυκνότητας του πληθυσμού του αιτίου της μόλυνσης, P. syringae pv. tabaci, σε φυτά Nicotiana benthamiana. In vitro πειράματα επιβεβαίωσαν ότι το στέλεχος MBI600, υπό συνθήκες έλλειψης σιδήρου, παράγει και εκκρίνει τον κατεχολικό σιδηροφορέα, bacillibactin. Τόσο οι δοκιμές in vitro όσο και in planta έδειξαν ότι η παραγωγή της bacillibactin είχε σαν αποτέλεσμα τη ενίσχυση της αντιμικροβιακής δράσης του ΜΒΙ600 μεταξύ των φυτοπαθογόνων βακτηρίων.Ακολούθως, προσδιορίστηκε η ικανότητα του στελέχους MBI600 να αποικίζει διαφορετικά είδη φυτικών ξενιστών. Τα αποτελέσματα επιβεβαίωσαν ότι το στέλεχος ΜΒΙ600 είναι ικανό να αποικίζει αποτελεσματικά τις ρίζες φυτών τομάτας και καλαμποκιού, καθώς και τα φύλλα φυτών τομάτας, Ν. Benthamiana και μαρουλιού, μετά την εφαρμογή του Serifel, κατά τρόπο δοσοεξαρτώμενο. Επιπλέον, χρησιμοποιώντας μικροβιολογικές δοκιμές και ποσοτική PCR αποδείχθηκε ότι τόσο οι εκκρινόμενες ουσίες της ρίζας όσο και τα φυτοπαθογόνα βακτήρια διεγείρουν την παραγωγή αντιβιοτικών του στελέχους ΜΒΙ600, την ομαδική κινητοποίηση και τον ανταγωνισμό. Τέλος, το εμπορικό στέλεχος B. amyloliquefaciens MBI600 αξιολογήθηκε ως προς την ικανότητά του να επάγει την ISR μετά από εφαρμογή με ριζοπότισμα ή ψεκασμό φύλλων φυτών τομάτας. Επίσης, το Φιλτραρισμένο Υπερκείμενο Κυτταρικής Καλλιέργειας (ΦΥΚΚ) του ΜΒΙ600 δοκιμάστηκε σε φυτά και σπορόφυτα τομάτας. Τα επίπεδα έκφρασης 23 γονιδίων-δεικτών, που εμπλέκονται σε μονοπάτια σηματοδότησης του σαλικυλικού οξέος (SA) και των αιθυλενίου/γιασμονικού οξέος (ET/JA), αξιολογήθηκαν με ποσοτική PCR πραγματικού χρόνου. Η εφαρμογή του Serifel στο φύλλο ενεργοποίησε τους αμυντικούς μηχανισμούς των φυτών με τρόπο δοσοεξαρτώμενο. Η χαμηλή συγκέντρωση ενεργοποίησε γονίδια του μονοπατιού σηματοδότησης του SA (npr1, pr1b1). Από την άλλη μεριά, η χρήση της προτεινόμενης συγκέντρωσης του Serifel είχε ως αποτέλεσμα την ενεργοποίηση όλων των γονιδίων απόκρισης των μονοπατιών σηματοδότησης των JA / ET που αξιολογήθηκαν (erf1, loxD, myc2), διατηρώντας ενεργό το μονοπάτι σηματοδότησης του SA. Αυτά τα αποτελέσματα υποδηλώνουν μια συνέργεια μεταξύ των μονοπατιών του SA και των JA / ET, κάτι που επιβεβαιώθηκε και με παρόμοια ανάλυση μετά την εφαρμογή των μεταβολιτών (ΦΥΚΚ) του MBI600. Επιπλέον, οι μεταβολίτες MBI600 κατέστειλαν το μονοπάτι σηματοδότησης του αμπσισικού (ΑΒΑ) ενώ ενίσχυσαν αυτό της αυξίνης. Επίσης, ενεργοποίησαν συστατικά των οδών βιοσύνθεσης και σηματοδότησης του γιασμονικού οξέος (JA) και του αιθυλενίου (ΕΤ). Σε αντίθεση με την εφαρμογή στο φύλλο, το ΦΥΚΚ δεν επηρέασε τα υπό μελέτη γονίδια που σχετίζονται με το μονοπάτι σηματοδότησης του SA.

scholarly journals Triple Gene Block Protein Interactions Involved in Movement of Barley Stripe Mosaic Virus

2008 ◽  
Vol 82 (10) ◽  
pp. 4991-5006 ◽  
Author(s):  
Hyoun-Sub Lim ◽  
Jennifer N. Bragg ◽  
Uma Ganesan ◽  
Diane M. Lawrence ◽  
Jialin Yu ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Triple Gene Block ◽  
Cell Movement ◽  
Wild Type Virus ◽  
Barley Stripe Mosaic Virus ◽  
Wild Type ◽  
In Planta ◽  
Gene Block ◽  
Physical Interactions

ABSTRACT Barley stripe mosaic virus (BSMV) encodes three movement proteins in an overlapping triple gene block (TGB), but little is known about the physical interactions of these proteins. We have characterized a ribonucleoprotein (RNP) complex consisting of the TGB1 protein and plus-sense BSMV RNAs from infected barley plants and have identified TGB1 complexes in planta and in vitro. Homologous TGB1 binding was disrupted by site-specific mutations in each of the first two N-terminal helicase motifs but not by mutations in two C-terminal helicase motifs. The TGB2 and TGB3 proteins were not detected in the RNP, but affinity chromatography and yeast two-hybrid experiments demonstrated that TGB1 binds to TGB3 and that TGB2 and TGB3 form heterologous interactions. These interactions required the TGB2 glycine 40 and the TGB3 isoleucine 108 residues, and BSMV mutants containing these amino acid substitution were unable to move from cell to cell. Infectivity experiments indicated that TGB1 separated on a different genomic RNA from TGB2 and TGB3 could function in limited cell-to-cell movement but that the rates of movement depended on the levels of expression of the proteins and the contexts in which they are expressed. Moreover, elevated expression of the wild-type TGB3 protein interfered with cell-to-cell movement but movement was not affected by the similar expression of a TGB3 mutant that fails to interact with TGB2. These experiments suggest that BSMV movement requires physical interactions of TGB2 and TGB3 and that substantial deviation from the TGB protein ratios expressed by the wild-type virus compromises movement.

scholarly journals A Polyamine Oxidase from Selaginella lepidophylla (SelPAO5) can Replace AtPAO5 in Arabidopsis through Converting Thermospermine to Norspermidine instead to Spermidine

Plants ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 99 ◽  
Author(s):  
G. H. M. Sagor ◽  
Tomonobu Kusano ◽  
Thomas Berberich
Keyword(s):  
Normal Values ◽  
Normal Growth ◽  
Polyamine Oxidase ◽  
Loss Of Function ◽  
Wild Type ◽  
In Planta ◽  
Selaginella Lepidophylla ◽  
Growth Phenotype ◽  
Polyamine Oxidases

Of the five polyamine oxidases in Arabidopsis thaliana, AtPAO5 has a substrate preference for the tetraamine thermospermine (T-Spm) which is converted to triamine spermidine (Spd) in a back-conversion reaction in vitro. A homologue of AtPAO5 from the lycophyte Selaginella lepidophylla (SelPAO5) back-converts T-Spm to the uncommon polyamine norspermidine (NorSpd) instead of Spd. An Atpao5 loss-of-function mutant shows a strong reduced growth phenotype when growing on a T-Spm containing medium. When SelPAO5 was expressed in the Atpao5 mutant, T-Spm level decreased to almost normal values of wild type plants, and NorSpd was produced. Furthermore the reduced growth phenotype was cured by the expression of SelPAO5. Thus, a NorSpd synthesis pathway by PAO reaction and T-Spm as substrate was demonstrated in planta and the assumption that a balanced T-Spm homeostasis is needed for normal growth was strengthened.

A Novel 2 Amino Acids Deletion in the Leucine Zipper Domain of C/EBPε Leads to Neutrophil-Specific Granule Deficiency (SGD)

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4101-4101
Author(s):  
Tadayuki Akagi ◽  
Taizo Wada ◽  
Masahiro Muraoka ◽  
Tomoko Toma ◽  
Kenzo Kaji ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Leucine Zipper ◽  
Molecular Mechanisms ◽  
Conflicts Of Interest ◽  
Wild Type ◽  
Nih3t3 Cells ◽  
Endogenous Expression ◽  
Leucine Zipper Domain ◽  
Type C ◽  
Specific Granule

Abstract Neutrophil-specific granule deficiency (SGD) is a rare congenital disorder. Neutrophils of SGD patients show abnormal bilobed nuclei and lack secondary and tertiary granule gene expression. Since neutrophils of SGD patients are deficient for bactericidal activity, the patients display immunodeficiency and suffer from frequent and severe infections. The transcription factor CCAAT/enhancer binding protein epsilon (C/EBPε) is one of the major regulators of granulopoiesis and is known to be the responsible gene for the disease. At least two homozygous germline mutations (5bp deletion and A-nucleotide insertion) of C/EBPε, which are functionally defective, have been reported. Here, we report a novel in-frame deletion of the C/EBPεgene in a 55 years-old female patient with a life-long history of recalcitrant skin infections with ulcer and scar formation. Peripheral blood smear showed characteristic changes, including reduction of cytoplasmic granules and increased bilobed nuclei of the neutrophils, monocytosis, absence of eosinophils and increased basophils. Flow cytometric examination revealed significant reduction of CD16 and abnormal expression of CD14 on the neutrophil surface. Sequencing of the C/EBPε gene revealed a homozygous deletion of 6 base-pairs (arginine and serine residues deletion; ΔRS) within the leucine zipper domain. Activation of luciferase driven by G-CSF receptor promoter was not induced by ΔRS; and endogenous expression of granule genes, including B9, NGAL and lactoferrin, was induced by wild-type C/EBPε but not by ΔRS in NIH3T3 cells, suggesting that transcriptional activity of ΔRS was diminished. GFP-tagged ΔRS, as well as wild-type C/EBPε, were localized to the nucleus in NIH3T3 cells, and DNA binding activity of ΔRS, which was determined by biotin-labeled DNA pulldown assay, was intact. Meanwhile, ΔRS together with Gata1 and PU.1 were not able to induce expression of eosinophil major basic protein (MBP) in NIH3T3 cells. Of note, wild-type C/EBPε associated with Gata1; however, ΔRS did not interact with Gata1, indicating that the ΔRS likely impairs protein-protein interaction of other transcription factors resulting in loss of transcriptional activation. These results further support the importance of the leucine zipper domain of C/EBPε for its essential function and indicate multiple molecular mechanisms leading to SGD. Disclosures No relevant conflicts of interest to declare.

In vitro cellulolytic activity of the plant pathogen Clavibacter michiganensis subsp. sepedonicus

1995 ◽  
Vol 41 (10) ◽  
pp. 877-888 ◽  
Author(s):  
Debra Baer ◽  
Neil C. Gudmestad
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Protein Band ◽  
Cellulolytic Activity ◽  
Clavibacter Michiganensis ◽  
Endoglucanase Activity ◽  
Clavibacter Michiganensis Subsp ◽  
Cellulose Substrates ◽  
Key Words Cellulase

The activity of four Clavibacter michiganensis subsp. sepedonicus strains against various cellulose substrates was investigated. Sixty-seven Clavibacter michiganensis subsp. sepedonicus strains grew well on media amended with carboxymethylcellulose, 64 strains produced zones of hydrolysis. Endoglucanase activity was optimal at 37 °C and pH 6.0 against carboxymethylcellulose incorporated in plate assays. Zymogram and sodium dodecyl sulfate – polyacrylamide gel electrophoresis revealed the presence of a protein band corresponding to the cellulolytic activity in the molecular weight (MW) range of approximately 28 000. Protein bands in the same range were detected in five Clavibacter michiganensis subsp. sepedonicus strains. Studies on crude enzyme extracts of Clavibacter michiganensis subsp. sepedonicus strain N-1-1 revealed that p-nitrophenyl β-D-cellobioside (pNPC) was hydrolyzed, with optimal activity at 37 °C and pH 7.0.Key words: cellulase, endo-1,4-β-glucanase (EC 3.2.1.4), Corynebacterium sepedonicum, Solanum tuberosum.

scholarly journals Flow-cytometric microglial sorting coupled with quantitative proteomics identifies moesin as a highly-abundant microglial protein with relevance to Alzheimer’s disease

2019 ◽  
Author(s):  
Sruti Rayaprolu ◽  
Tianwen Gao ◽  
Hailian Xiao ◽  
Supriya Ramesha ◽  
Laura D. Weinstock ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cell Sorting ◽  
Ribosomal Proteins ◽  
Molecular Mechanisms ◽  
Synaptic Proteins ◽  
Wild Type ◽  
Proteomic Data ◽  
Core Set

AbstractBackgroundProteomic characterization of microglia provides the most proximate assessment of functionally relevant molecular mechanisms of neuroinflammation. However, microglial proteomics studies have been limited by low cellular yield and contamination by non-microglial proteins using existing enrichment strategies.MethodsWe coupled magnetic-activated cell sorting (MACS) and fluorescence activated cell sorting (FACS) of microglia with tandem mass tag-mass spectrometry (TMT-MS) to obtain a highly-pure microglial proteome and identified a core set of highly-abundant microglial proteins in adult mouse brain. We interrogated existing human proteomic data for Alzheimer’s disease (AD) relevance of highly-abundant microglial proteins and performed immuno-histochemical and in-vitro validation studies.ResultsQuantitative multiplexed proteomics by TMT-MS of CD11b+ MACS-enriched (N = 5 mice) and FACS-isolated (N = 5 mice), from adult wild-type mice, identified 1,791 proteins. A total of 203 proteins were highly abundant in both datasets, representing a core-set of highly abundant microglial proteins. In addition, we found 953 differentially enriched proteins comparing MACS and FACS-based approaches, indicating significant differences between both strategies. The FACS-isolated microglia proteome was enriched with cytosolic, endoplasmic reticulum, and ribosomal proteins involved in protein metabolism and immune system functions, as well as an abundance of canonical microglial proteins. Conversely, the MACS-enriched microglia proteome was enriched with mitochondrial and synaptic proteins and higher abundance of neuronal, oligodendrocytic and astrocytic proteins. From the 203 consensus microglial proteins with high abundance in both datasets, we confirmed microglial expression of moesin (Msn) in wild-type and 5xFAD mouse brains as well as in human AD brains. Msn expression is nearly exclusively found in microglia that surround Aβ plaques in 5xFAD brains. In in-vitro primary microglial studies, Msn silencing by siRNA decreased Aβ phagocytosis and increased lipopolysaccharide-induced production of the pro-inflammatory cytokine, tumor necrosis factor (TNF). In network analysis of human brain proteomic data, Msn was a hub protein of an inflammatory co-expression module positively associated with AD neuropathological features and cognitive dysfunction.ConclusionsUsing FACS coupled with TMT-MS as the method of choice for microglial proteomics, we define a core set of highly-abundant adult microglial proteins. Among these, we validate Msn as highly-abundant in plaque-associated microglia with relevance to human AD.

scholarly journals Identification of a putative DNA-binding protein in Arabidopsis that acts as a susceptibility hub and interacts with multiple Pseudomonas syringae effectors

2020 ◽  
Author(s):  
Karl Schreiber ◽  
Jennifer D Lewis
Keyword(s):  
Pseudomonas Syringae ◽  
Transcriptional Profiling ◽  
Effector Proteins ◽  
Ribosomal Protein Genes ◽  
Loss Of Function ◽  
Wild Type ◽  
In Planta ◽  
Arabidopsis Protein ◽  
Wide Range

Phytopathogens use secreted effector proteins to suppress host immunity and promote pathogen virulence, and there is increasing evidence that the host-pathogen interactome comprises a complex network. In an effort to identify novel interactors of the Pseudomonas syringae effector HopZ1a, we performed a yeast two-hybrid screen that identified a previously uncharacterized Arabidopsis protein that we designate HopZ1a Interactor 1 (ZIN1). Additional analyses in yeast and in planta revealed that ZIN1 also interacts with several other P. syringae effectors. We show that an Arabidopsis loss-of-function zin1 mutant is less susceptible to infection by certain strains of P. syringae, while overexpression of ZIN1 results in enhanced susceptibility. Functionally, ZIN1 exhibits topoisomerase-like activity in vitro. Transcriptional profiling of wild-type and zin1 Arabidopsis plants inoculated with P. syringae indicated that while ZIN1 regulates a wide range of pathogen-responsive biological processes, the list of genes more highly expressed in zin1 versus wild-type plants was particularly enriched for ribosomal protein genes. Altogether, these data illuminate ZIN1 as a potential susceptibility hub that interacts with multiple effectors to influence the outcome of plant-microbe interactions.

scholarly journals The TUTase URT1 connects decapping activators and prevents the accumulation of excessively deadenylated mRNAs to avoid siRNA biogenesis

2020 ◽  
Author(s):  
Hélène Scheer ◽  
Caroline de Almeida ◽  
Emilie Ferrier ◽  
Quentin Simonnot ◽  
Laure Poirier ◽  
...  
Keyword(s):  
Rna Sequencing ◽  
Growth And Development ◽  
Molecular Mechanisms ◽  
Tail Length ◽  
Mrna Degradation ◽  
In Planta ◽  
Rna Helicases ◽  
Eukaryotic Mrnas

AbstractUridylation is a widespread modification destabilizing eukaryotic mRNAs. Yet, molecular mechanisms underlying TUTase-mediated mRNA degradation remain mostly unresolved. Here, we report that the Arabidopsis TUTase URT1 participates in a molecular network connecting several translational repressors/decapping activators. URT1 directly interacts with DECAPPING 5 (DCP5), the Arabidopsis ortholog of human LSM14 and yeast Scd6, and this interaction connects URT1 to additional decay factors like DDX6/Dhh1-like RNA helicases. Nanopore direct RNA sequencing reveals a global role of URT1 in shaping poly(A) tail length, notably by preventing the accumulation of excessively deadenylated mRNAs. Based on in vitro and in planta data, we propose a model that explains how URT1 could reduce the accumulation of oligo(A)-tailed mRNAs both by favoring their degradation and because 3’ terminal uridines intrinsically hinder deadenylation. Importantly, preventing the accumulation of excessively deadenylated mRNAs avoids the biogenesis of illegitimate siRNAs that silence endogenous mRNAs and perturb Arabidopsis growth and development.

scholarly journals Fitodefensivos em plantas medicinais: macromoléculas hidrofílicas de folhas de mil folhas (Achillea millefolium L.) inibem o crescimento in vitro de bactérias fitopatogênicas

2013 ◽  
Vol 15 (2) ◽  
pp. 180-187
Author(s):  
N.G. Tessarollo ◽  
L.C. Carrijo ◽  
M.O. Barbosa ◽  
H.O. Almeida ◽  
T.H.A. Pereira ◽  
...  
Keyword(s):  
Ralstonia Solanacearum ◽  
Achillea Millefolium ◽  
Clavibacter Michiganensis ◽  
Clavibacter Michiganensis Subsp

Extratos aquosos da planta medicinal Achillea millefolium contêm macromoléculas de interesse para desenvolver fitodefensivos para a agricultura. Duas frações de mil folhas foram obtidas por ultrafiltração, E1 (contendo moléculas maiores que 30 kDa), e E3 (peptídeos entre 1 e 10 kDa) que inibiram o crescimento das bactérias fitopatogênicas Ralstonia solanacearum, gram-negativa, e Clavibacter michiganensis subsp. michiganensis, gram-positiva, com dependência de concentração. Os valores de concentração inibitória mínima (CIM) para ambos os extratos e bactérias foram baixos, entre 20 e 80µM. A CIM relativa à proteína total evidenciou a presença de macromoléculas muito ativas em E3, embora com baixa concentração proteica. E3 se aplica à prospecção de peptídeos antimicrobianos. Estimar a CIM relativa à quantidade de amostra vegetal valorizou o potencial antimicrobiano natural de E1, que contém alta concentração proteica. E1e E3 se aplicam ao desenvolvimento de fitodefensivos para uso biotecnológico. A ultrafiltração fracionou as amostras de forma nativa, rápida, e com baixo custo; além de dessalinizar, clarificar, purificar, e concentrar E1 e E3. Esse estudo inédito sobre a separômica e a ação antimicrobiana de extratos macromoleculares aquosos de mil folhas sugere que plantas cicatrizantes podem apresentar grande potencial para desenvolver fitodefensivos agrícolas naturais não danosos, à semelhança de medicamentos fitoterápicos.

scholarly journals (264) In Vitro Pollen Germination of Wild Type and Transgenic `Galia' Male Parental Line Melon [Cucumis melo (L.) var. reticulatus Ser.]

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1016A-1016
Author(s):  
Hector G. Nunez-Palenius ◽  
Daniel J. Cantliffe ◽  
Harry J. Klee ◽  
Don J. Huber
Keyword(s):  
Pollen Tube ◽  
Pollen Germination ◽  
Transgenic Line ◽  
Fruit Set ◽  
Acc Oxidase ◽  
Parental Line ◽  
Wild Type ◽  
Antisense Gene ◽  
Germination Timing

Pollen germination timing has a paramount role in fertilization of a flower. Rapid germination and outgrowth of a pollen tube that penetrates the stigma is required. Physical and biological factors can affect pollen germination timing. The objective of this study was to determine if ACC oxidase antisense gene expression could influence in vitro pollen germination and in vitro pollen tube length growth. A transgenic (ACC oxidase antisense) `Galia' male parental line had a reduced fruit set compared to its wild type. Likewise, embryo abortion and empty seeds after self-pollination in a `Galia' male parental line were observed. Wild type and transgenic `Galia' male parental line melon plants were grown in a greenhouse according to the practices of Rodriguez (2003). Male flowers were collected from these plants between 10 to 12 am; pollen was obtained by dipping the anther in germination medium (10.25% sucrose, 0.031% calcium nitrate, 0.015% boric acid, 0.0075% KNO3, and 0.016% MgSO4) at 25 °C and analyzed immediately, either for total percentage of germination after 5 minutes of incubation or to measure pollen tube growth rate every 5 minutes during 1 hour. Each flower provided an average of 250 pollen grains. Assays were conducted by using the “Hanging Drop Method” (Okay and Ayfer, 1994). Percentage of pollen germination in WT `Galia' male parental line was greater than the transgenic line. Likewise, in vitro pollen tube growth in wild type `Galia' melon was greater than pollen from the transgenic line. Possibly the ACC oxidase antisense gene expression in `Galia' male parental line may have had an influence on the reduced fruit set observed.

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