Unveiling the Role Displayed by Penicillium digitatum PdMut3 Transcription Factor in Pathogen–Fruit Interaction

Zn2Cys6 transcription factors are unique to fungi and are involved in different regulatory functions. In this study, we have identified the Penicillium digitatumPdMut3 gene, which encodes a putative Zn (II) 2Cys6 DNA-binding protein. Elimination of PdMut3 in Pd1 strain caused increased virulence during citrus infection. The transcription of the PdMut3 gene showed a higher expression rate during fungal growth and less transcription during fruit infection. Furthermore, the deletion of the gene in the wild-type isolate of P. digitatum did not produce any modification of the sensitivity to different fungicides, indicating that the gene is not associated with resistance to fungicides. In contrast, PdMut3 null mutants showed a reduction in growth in minimal media, which was associated with severe alterations in conidiophore development and morphological alterations of the hyphae. Mutants showed greater sensitivity to compounds that interfere with the cell wall and an invasive growth block. Thus, PdMut3 might have an indirect role in fungi virulence through metabolism and peroxisomes development.

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Ultrastructure of melanin formation in Verticillium dahliae with (+)-scytalone as a biosynthetic intermediate

Canadian Journal of Microbiology ◽

10.1139/m76-103 ◽

1976 ◽

Vol 22 (5) ◽

pp. 702-711 ◽

Cited By ~ 30

Author(s):

M. H. Wheeler ◽

W. J. Tolmsoff ◽

S. Meola

Keyword(s):

Verticillium Dahliae ◽

Cell Walls ◽

Maximum Rate ◽

Melanin Synthesis ◽

Wild Type ◽

Type Isolate ◽

Albino Mutant ◽

In The Wild ◽

Fibrillar Network ◽

Scanning Electron

Transmission and scanning electron microscopy showed that melanin of wild-type Verticillium dahliae occurred as granules in microsclerotial cell walls and in a fibrillar network encapsulating the walls. An albino microsclerotial mutant and a brown microsclerotial mutant of V. dahliae did not form melanin granules. When albino microsclerotia were treated with (+)-scytalone (a metabolite that the brown mutant accumulates), they formed melanin granules and turned black. These granules were similar in appearance and distribution to those in the wild type. Melanin granules of the wild-type isolate and the scytalone-treated albino mutant were formed at a maximum rate in microsclerotia from 5- to 8-day-old cultures. These observations suggest that scytalone is a natural intermediate of melanin synthesis in V. dahliae.

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Redox crisis underlies conditional light–dark lethality in cyanobacterial mutants that lack the circadian regulator, RpaA

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1613078114 ◽

2017 ◽

Vol 114 (4) ◽

pp. E580-E589 ◽

Cited By ~ 23

Author(s):

Spencer Diamond ◽

Benjamin E. Rubin ◽

Ryan K. Shultzaberger ◽

You Chen ◽

Chase D. Barber ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Response Regulator ◽

Mechanistic Explanation ◽

Growth Conditions ◽

Oxygen Species ◽

Wild Type ◽

Profound Influence ◽

In The Wild ◽

Pcc 7942 ◽

Null Mutants

Cyanobacteria evolved a robust circadian clock, which has a profound influence on fitness and metabolism under daily light–dark (LD) cycles. In the model cyanobacterium Synechococcus elongatus PCC 7942, a functional clock is not required for diurnal growth, but mutants defective for the response regulator that mediates transcriptional rhythms in the wild-type, regulator of phycobilisome association A (RpaA), cannot be cultured under LD conditions. We found that rpaA-null mutants are inviable after several hours in the dark and compared the metabolomes of wild-type and rpaA-null strains to identify the source of lethality. Here, we show that the wild-type metabolome is very stable throughout the night, and this stability is lost in the absence of RpaA. Additionally, an rpaA mutant accumulates excessive reactive oxygen species (ROS) during the day and is unable to clear it during the night. The rpaA-null metabolome indicates that these cells are reductant-starved in the dark, likely because enzymes of the primary nighttime NADPH-producing pathway are direct targets of RpaA. Because NADPH is required for processes that detoxify ROS, conditional LD lethality likely results from inability of the mutant to activate reductant-requiring pathways that detoxify ROS when photosynthesis is not active. We identified second-site mutations and growth conditions that suppress LD lethality in the mutant background that support these conclusions. These results provide a mechanistic explanation as to why rpaA-null mutants die in the dark, further connect the clock to metabolism under diurnal growth, and indicate that RpaA likely has important unidentified functions during the day.

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Freeze-substituted fungal cells of Nectria haematococca: A comparison of the macroconidial walls of the adhesion-competent wild type with an adhesion-reduced mutant

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160996 ◽

1990 ◽

Vol 48 (3) ◽

pp. 688-689

Author(s):

Thecan Caesar-Ton That ◽

Lynn Epstein

Keyword(s):

Freeze Substitution ◽

Uranyl Acetate ◽

Wild Type ◽

Nectria Haematococca ◽

Fruit Extract ◽

Dialysis Tubing ◽

Tube Emergence ◽

Contrast Microscopy ◽

In The Wild ◽

Freeze Damage

Nectria haematococca mating population I (anamorph, Fusarium solani) macroconidia attach to its host (squash) and non-host surfaces prior to germ tube emergence. The macroconidia become adhesive after a brief period of protein synthesis. Recently, Hickman et al. (1989) isolated N. haematococca adhesion-reduced mutants. Using freeze substitution, we compared the development of the macroconidial wall in the wild type in comparison to one of the mutants, LEI.Macroconidia were harvested at 1C, washed by centrifugation, resuspended in a dilute zucchini fruit extract and incubated from 0 - 5 h. During the incubation period, wild type macroconidia attached to uncoated dialysis tubing. Mutant macroconidia did not attach and were collected on poly-L-lysine coated dialysis tubing just prior to freezing. Conidia on the tubing were frozen in liquid propane at 191 - 193C, substituted in acetone with 2% OsO4 and 0.05% uranyl acetate, washed with acetone, and flat-embedded in Epon-Araldite. Using phase contrast microscopy at 1000X, cells without freeze damage were selected, remounted, sectioned and post-stained sequentially with 1% Ba(MnO4)2 2% uranyl acetate and Reynold’s lead citrate. At least 30 cells/treatment were examined.

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Rad51-Independent Interchromosomal Double-Strand Break Repair by Gene Conversion Requires Rad52 but Not Rad55, Rad57, or Dmc1

Molecular and Cellular Biology ◽

10.1128/mcb.00524-07 ◽

2007 ◽

Vol 28 (3) ◽

pp. 897-906 ◽

Cited By ~ 21

Author(s):

Thomas J. Pohl ◽

Jac A. Nickoloff

Keyword(s):

Gene Conversion ◽

Strand Break ◽

Double Strand Break ◽

Single Strand ◽

Homology Search ◽

Wild Type ◽

Dsb Repair ◽

Single Strand Annealing ◽

In The Wild ◽

Break Induced Replication

ABSTRACT Homologous recombination (HR) is critical for DNA double-strand break (DSB) repair and genome stabilization. In yeast, HR is catalyzed by the Rad51 strand transferase and its “mediators,” including the Rad52 single-strand DNA-annealing protein, two Rad51 paralogs (Rad55 and Rad57), and Rad54. A Rad51 homolog, Dmc1, is important for meiotic HR. In wild-type cells, most DSB repair results in gene conversion, a conservative HR outcome. Because Rad51 plays a central role in the homology search and strand invasion steps, DSBs either are not repaired or are repaired by nonconservative single-strand annealing or break-induced replication mechanisms in rad51Δ mutants. Although DSB repair by gene conversion in the absence of Rad51 has been reported for ectopic HR events (e.g., inverted repeats or between plasmids), Rad51 has been thought to be essential for DSB repair by conservative interchromosomal (allelic) gene conversion. Here, we demonstrate that DSBs stimulate gene conversion between homologous chromosomes (allelic conversion) by >30-fold in a rad51Δ mutant. We show that Rad51-independent allelic conversion and break-induced replication occur independently of Rad55, Rad57, and Dmc1 but require Rad52. Unlike DSB-induced events, spontaneous allelic conversion was detected in both rad51Δ and rad52Δ mutants, but not in a rad51Δ rad52Δ double mutant. The frequencies of crossovers associated with DSB-induced gene conversion were similar in the wild type and the rad51Δ mutant, but discontinuous conversion tracts were fivefold more frequent and tract lengths were more widely distributed in the rad51Δ mutant, indicating that heteroduplex DNA has an altered structure, or is processed differently, in the absence of Rad51.

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Effects of Mutations of RAD50, RAD51, RAD52, and Related Genes on Illegitimate Recombination in Saccharomyces cerevisiae

Genetics ◽

10.1093/genetics/142.2.383 ◽

1996 ◽

Vol 142 (2) ◽

pp. 383-391 ◽

Cited By ~ 2

Author(s):

Yasumasa Tsukamoto ◽

Jun-ichi Kato ◽

Hideo Ikeda

Keyword(s):

Saccharomyces Cerevisiae ◽

Quantitative Analysis ◽

Structural Analysis ◽

Recombination Rate ◽

Type Strain ◽

Negative Selection ◽

Wild Type Strain ◽

Illegitimate Recombination ◽

Wild Type ◽

In The Wild

Abstract To examine the mechanism of illegitimate recombination in Saccharomyces cerevisiae, we have developed a plasmid system for quantitative analysis of deletion formation. A can1 cyh2 cell carrying two negative selection markers, the CAN1 and CYH2 genes, on a YCp plasmid is sensitive to canavanine and cycloheximide, but the cell becomes resistant to both drugs when the plasmid has a deletion over the CAN1 and CYH2 genes. Structural analysis of the recombinant plasmids obtained from the resistant cells showed that the plasmids had deletions at various sites of the CAN1-CYH2 region and there were only short regions of homology (1-5 bp) at the recombination junctions. The results indicated that the deletion detected in this system were formed by illegitimate recombination. Study on the effect of several rad mutations showed that the recombination rate was reduced by 30-, 10-, 10-, and 10-fold in the rad52, rad50, mre11, and xrs2 mutants, respectively, while in the rud51, 54, 55, and 57 mutants, the rate was comparable to that in the wild-type strain. The rad52 mutation did not affect length of homology at junction sites of illegitimate recombination.

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Transcriptome Analysis Provides Insights into the Mechanism of Astaxanthin Enrichment in a Mutant of the Ridgetail White Prawn Exopalaemon carinicauda

Genes ◽

10.3390/genes12050618 ◽

2021 ◽

Vol 12 (5) ◽

pp. 618

Author(s):

Yue Jin ◽

Shihao Li ◽

Yang Yu ◽

Chengsong Zhang ◽

Xiaojun Zhang ◽

...

Keyword(s):

Transcriptome Analysis ◽

Underlying Mechanism ◽

Biological Processes ◽

Wild Type ◽

Expression Levels ◽

In The Wild ◽

Cuticle Proteins ◽

Apolipoprotein D ◽

High Level ◽

Lower Expression

A mutant of the ridgetail white prawn, which exhibited rare orange-red body color with a higher level of free astaxanthin (ASTX) concentration than that in the wild-type prawn, was obtained in our lab. In order to understand the underlying mechanism for the existence of a high level of free astaxanthin, transcriptome analysis was performed to identify the differentially expressed genes (DEGs) between the mutant and wild-type prawns. A total of 78,224 unigenes were obtained, and 1863 were identified as DEGs, in which 902 unigenes showed higher expression levels, while 961 unigenes presented lower expression levels in the mutant in comparison with the wild-type prawns. Based on Gene Ontology analysis and Kyoto Encyclopedia of Genes and Genomes analysis, as well as further investigation of annotated DEGs, we found that the biological processes related to astaxanthin binding, transport, and metabolism presented significant differences between the mutant and the wild-type prawns. Some genes related to these processes, including crustacyanin, apolipoprotein D (ApoD), cathepsin, and cuticle proteins, were identified as DEGs between the two types of prawns. These data may provide important information for us to understand the molecular mechanism of the existence of a high level of free astaxanthin in the prawn.

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cot1: A Regulator of Arabidopsis Trichome Initiation

Genetics ◽

10.1093/genetics/149.2.565 ◽

1998 ◽

Vol 149 (2) ◽

pp. 565-577

Author(s):

Daniel B Szymanski ◽

Daniel A Klis ◽

John C Larkin ◽

M David Marks

Keyword(s):

Cell Fate ◽

Gene Dosage ◽

Signal Transduction Pathway ◽

Spatial Arrangement ◽

Complex Signal ◽

Chromosome 2 ◽

Wild Type ◽

Trichome Formation ◽

In The Wild ◽

Leaf Trichome

Abstract In Arabidopsis, the timing and spatial arrangement of trichome initiation is tightly regulated and requires the activity of the GLABROUS1 (GL1) gene. The COTYLEDON TRICHOME 1 (COT1) gene affects trichome initiation during late stages of leaf development and is described in this article. In the wild-type background, cot1 has no observable effect on trichome initiation. GL1 overexpression in wild-type plants leads to a modest number of ectopic trichomes and to a decrease in trichome number on the adaxial leaf surface. The cot1 mutation enhances GL1-overexpression-dependent ectopic trichome formation and also induces increased leaf trichome initiation. The expressivity of the cot1 phenotype is sensitive to cot1 and 35S::GL1 gene dosage, and the most severe phenotypes are observed when cot1 and 35S::GL1 are homozygous. The COT1 locus is located on chromosome 2 15.3 cM north of er. Analysis of the interaction between cot1, try, and 35S::GL1 suggests that COT1 is part of a complex signal transduction pathway that regulates GL1-dependent adoption of the trichome cell fate.

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Transcriptome Changes in Pseudomonas putida KT2440 during Medium-Chain-Length Polyhydroxyalkanoate Synthesis Induced by Nitrogen Limitation

International Journal of Molecular Sciences ◽

10.3390/ijms22010152 ◽

2020 ◽

Vol 22 (1) ◽

pp. 152

Author(s):

Dorota Dabrowska ◽

Justyna Mozejko-Ciesielska ◽

Tomasz Pokój ◽

Slawomir Ciesielski

Keyword(s):

Chain Length ◽

Nitrogen Limitation ◽

Stringent Response ◽

Wild Type ◽

Pseudomonas Putida Kt2440 ◽

Medium Chain ◽

Environmental Stimuli ◽

Medium Chain Length ◽

In The Wild

Pseudomonas putida’s versatility and metabolic flexibility make it an ideal biotechnological platform for producing valuable chemicals, such as medium-chain-length polyhydroxyalkanoates (mcl-PHAs), which are considered the next generation bioplastics. This bacterium responds to environmental stimuli by rearranging its metabolism to improve its fitness and increase its chances of survival in harsh environments. Mcl-PHAs play an important role in central metabolism, serving as a reservoir of carbon and energy. Due to the complexity of mcl-PHAs’ metabolism, the manner in which P. putida changes its transcriptome to favor mcl-PHA synthesis in response to environmental stimuli remains unclear. Therefore, our objective was to investigate how the P. putida KT2440 wild type and mutants adjust their transcriptomes to synthesize mcl-PHAs in response to nitrogen limitation when supplied with sodium gluconate as an external carbon source. We found that, under nitrogen limitation, mcl-PHA accumulation is significantly lower in the mutant deficient in the stringent response than in the wild type or the rpoN mutant. Transcriptome analysis revealed that, under N-limiting conditions, 24 genes were downregulated and 21 were upregulated that were common to all three strains. Additionally, potential regulators of these genes were identified: the global anaerobic regulator (Anr, consisting of FnrA, Fnrb, and FnrC), NorR, NasT, the sigma54-dependent transcriptional regulator, and the dual component NtrB/NtrC regulator all appear to play important roles in transcriptome rearrangement under N-limiting conditions. The role of these regulators in mcl-PHA synthesis is discussed.

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CAND2/PMTR1 Is Required for Melatonin-Conferred Osmotic Stress Tolerance in Arabidopsis

International Journal of Molecular Sciences ◽

10.3390/ijms22084014 ◽

2021 ◽

Vol 22 (8) ◽

pp. 4014

Author(s):

Lin-Feng Wang ◽

Ting-Ting Li ◽

Yu Zhang ◽

Jia-Xing Guo ◽

Kai-Kai Lu ◽

...

Keyword(s):

Osmotic Stress ◽

Stress Tolerance ◽

Wild Type Plant ◽

Wild Type ◽

Melatonin Receptor ◽

Ros Scavenging ◽

Exogenous Melatonin ◽

Osmotic Stress Tolerance ◽

Osmotic Stress Response ◽

In The Wild

Osmotic stress severely inhibits plant growth and development, causing huge loss of crop quality and quantity worldwide. Melatonin is an important signaling molecule that generally confers plant increased tolerance to various environmental stresses, however, whether and how melatonin participates in plant osmotic stress response remain elusive. Here, we report that melatonin enhances plant osmotic stress tolerance through increasing ROS-scavenging ability, and melatonin receptor CAND2 plays a key role in melatonin-mediated plant response to osmotic stress. Upon osmotic stress treatment, the expression of melatonin biosynthetic genes including SNAT1, COMT1, and ASMT1 and the accumulation of melatonin are increased in the wild-type plants. The snat1 mutant is defective in osmotic stress-induced melatonin accumulation and thus sensitive to osmotic stress, while exogenous melatonin enhances the tolerance of the wild-type plant and rescues the sensitivity of the snat1 mutant to osmotic stress by upregulating the expression and activity of catalase and superoxide dismutase to repress H2O2 accumulation. Further study showed that the melatonin receptor mutant cand2 exhibits reduced osmotic stress tolerance with increased ROS accumulation, but exogenous melatonin cannot revert its osmotic stress phenotype. Together, our study reveals that CADN2 functions necessarily in melatonin-conferred osmotic stress tolerance by activating ROS-scavenging ability in Arabidopsis.

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The Cloning and Molecular Analysis of pawn-B in Paramecium tetraurelia

Genetics ◽

10.1093/genetics/155.3.1105 ◽

2000 ◽

Vol 155 (3) ◽

pp. 1105-1117 ◽

Cited By ~ 4

Author(s):

W John Haynes ◽

Kit-Yin Ling ◽

Robin R Preston ◽

Yoshiro Saimi ◽

Ching Kung

Keyword(s):

Genomic Library ◽

Open Reading Frame ◽

Paramecium Tetraurelia ◽

Wild Type ◽

Rt Pcr ◽

Reading Frame ◽

Close Proximity ◽

In The Wild ◽

Dna Fragment ◽

Alternative Sites

Abstract Pawn mutants of Paramecium tetraurelia lack a depolarization-activated Ca2+ current and do not swim backward. Using the method of microinjection and sorting a genomic library, we have cloned a DNA fragment that complements pawn-B (pwB/pwB). The minimal complementing fragment is a 798-bp open reading frame (ORF) that restores the Ca2+ current and the backward swimming when expressed. This ORF contains a 29-bp intron and is transcribed and translated. The translated product has two putative transmembrane domains but no clear matches in current databases. Mutations in the available pwB alleles were found within this ORF. The d4-95 and d4-96 alleles are single base substitutions, while d4-662 (previously pawn-D) harbors a 44-bp insertion that matches an internal eliminated sequence (IES) found in the wild-type germline DNA except for a single C-to-T transition. Northern hybridizations and RT-PCR indicate that d4-662 transcripts are rapidly degraded or not produced. A second 155-bp IES in the wild-type germline ORF excises at two alternative sites spanning three asparagine codons. The pwB ORF appears to be separated from a 5′ neighboring ORF by only 36 bp. The close proximity of the two ORFs and the location of the pwB protein as indicated by GFP-fusion constructs are discussed.

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