scholarly journals De novo purine nucleotide biosynthesis mediated by amidophosphoribosyl transferase is required for conidiation and essential for the successful host colonization of Magnaporthe oryzae

2021 ◽  
Author(s):  
Osakina Aron ◽  
Min Wang ◽  
Jiayuan Guo ◽  
Jagero Frankline Otieno ◽  
Qussai Zuriegat ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
De Novo ◽  
Host Cells ◽  
Purine Biosynthesis ◽  
Pcr Analysis ◽  
Pathogenicity Test ◽  
Purine Nucleotide ◽  
In Planta ◽  
Host Colonization ◽  
Nucleotide Biosynthesis

Amidophosphoribosyl transferase catalyzes the first step of the purine nucleotide biosynthesis by converting 5-phosphoribosyl-1-pyrophosphate into 5-phosphoribosyl-1-amine. In this study, we identified and characterized the functions of MoAde4, an ortholog of yeast Ade4 in the rice blast fungus. MoAde4 is a 537-amino acid protein containing the GATase_6 and pribosyltran domains. Quantitative real-time PCR analysis showed MoADE4 transcripts were highly expressed during conidiation, early-infection, and late-infection stages of the fungus. Disruption of MoADE4 gene resulted in ΔMoade4 mutant exhibiting adenine, adenosine, and hypoxanthine auxotrophy on MM. Conidia quantification assays showed ΔMoade4 mutant was significantly reduced in sporulation. The conidia of ΔMoade4 mutant could still form appressoria but mostly failed to penetrate the rice cuticle. Pathogenicity test showed ΔMoade4 was completely nonpathogenic on rice and barley leaves which was attributed by failure of its infectious hyphae to colonize the host cells. The ΔMoade4 was defective in induction of strong host immunity and had its purine transporter genes repressed during in planta infection. Addition of exogenous adenine partially rescued conidiation and pathogenicity defects of the ΔMoade4 mutant on the barley and rice leaves. Localization assays showed that MoAde4 is located in the cytoplasm. Taken together, our results demonstrate that purine biosynthesis orchestrated by MoAde4 is required for fungal development, conidiation, more importantly, we found it to be essential for fungal pathogenicity not because of the appressorial formation, but appressorium penetration and host colonization during the plant infection of M. oryzae. Thus this findings suggests that purine biosynthesis could act as an important target for combating recalcitrant plant fungal pathogens.

scholarly journals The influence of ammonia on purine and pyrimidine nucleotide biosynthesis in rat liver and brain in vitro

1978 ◽  
Vol 172 (3) ◽  
pp. 457-464 ◽  
Author(s):  
Stephen D. Skaper ◽  
William E. O'Brien ◽  
Irwin A. Schafer
Keyword(s):  
De Novo ◽  
Liver Homogenate ◽  
Purine Biosynthesis ◽  
Purine Nucleotide ◽  
Carbamoyl Phosphate ◽  
Phosphoribosyl Pyrophosphate ◽  
Nucleotide Synthesis ◽  
Nucleotide Biosynthesis ◽  
Pyrimidine Nucleotide

1. The effect of ammonia on purine and pyrimidine nucleotide biosynthesis was studied in rat liver and brain in vitro. The incorporation of NaH14CO3 into acid-soluble uridine nucleotide (UMP) in liver homogenates and minces was increased 2.5–4-fold on incubation with 10mm-NH4Cl plus N-acetyl-l-glutamate, but not with either compound alone. 2. The incorporation of NaH14CO3 into orotic acid was increased 3–4-fold in liver homogenate with NH4Cl plus acetylglutamate. 3. The 5-phosphoribosyl 1-pyrophosphate content of liver homogenate was decreased by 50% after incubation for 10min with 10mm-NH4Cl plus acetylglutamate. 4. Concomitant with this decrease in free phosphoribosyl pyrophosphate was a 40–50% decrease in the rates of purine nucleotide synthesis, both de novo and from the preformed base. 5. Subcellular fractionation of liver indicated that the effects of NH4Cl plus acetylglutamate on pyrimidine and purine biosynthesis required a mitochondrial fraction. This effect of NH4Cl plus acetylglutamate could be duplicated in a mitochondria-free liver fraction with carbamoyl phosphate. 6. A similar series of experiments carried out with rat brain demonstrated a significant, though considerably smaller, effect on UMP synthesis de novo and purine base reutilization. 7. These data indicate that excessive amounts of ammonia may interfere with purine nucleotide biosynthesis by stimulating production of carbamoyl phosphate through the mitochondrial synthetase, with the excess carbamoyl phosphate in turn increasing pyrimidine nucleotide synthesis de novo and diminishing the phosphoribosyl pyrophosphate available for purine biosynthesis.

scholarly journals Disruption of de novo purine biosynthesis in Pseudomonas fluorescens Pf0-1 leads to reduced biofilm formation and a reduction in cell size of surface-attached but not planktonic cells

2015 ◽  
Author(s):  
Shiro Yoshioka ◽  
Peter D Newell
Keyword(s):  
Pseudomonas Fluorescens ◽  
Cell Size ◽  
Biofilm Formation ◽  
De Novo ◽  
Purine Biosynthesis ◽  
Model Organisms ◽  
Purine Nucleotides ◽  
Surface Attachment ◽  
Nucleotide Biosynthesis ◽  
Mutant Cells

Pseudomonas fluorescens Pf0-1 is one of the model organisms for biofilm research. Our previous transposon mutagenesis study suggested a requirement for the de novo purine nucleotide biosynthesis pathway for biofilm formation by this organism. This study was performed to verify that observation and investigate the basis for the defects in biofilm formation shown by purine biosynthesis mutants. Constructing deletion mutations in 8 genes in this pathway, we found that they all showed reductions in biofilm formation that could be partly or completely restored by nucleotide supplementation or genetic complementation. We demonstrated that, despite a reduction in biofilm formation, more viable mutant cells were recovered from the surface-attached population than from the planktonic phase under conditions of purine deprivation. Analyses using scanning electron microscopy revealed that the surface-attached mutant cells were 25~30% shorter in length than WT, which partly explains the reduced biomass in the mutant biofilms. The laser diffraction particle analyses confirmed this finding, and further indicated that the WT biofilm cells were smaller than their planktonic counterparts. The defects in biofilm formation and reductions in cell size shown by the mutants were fully recovered upon adenine or hypoxanthine supplementation, indicating that the purine shortages caused reductions in cell size. Our results are consistent with surface attachment serving as a survival strategy during nutrient deprivation, and indicate that changes in the cell size may be a natural response of P. fluorescens to growth on a surface. Finally, cell sizes in WT biofilms became slightly smaller in the presence of exogenous adenine than in its absence. Our findings suggest that purine nucleotides or related metabolites may influence the regulation of cell size in this bacterium.

scholarly journals The nucleotide pGpp acts as a third alarmone in Bacillus, with functions distinct from those of (p) ppGpp

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jin Yang ◽  
Brent W. Anderson ◽  
Asan Turdiev ◽  
Husan Turdiev ◽  
David M. Stevenson ◽  
...  
Keyword(s):  
Purine Biosynthesis ◽  
Ribosome Assembly ◽  
Bacterial Cells ◽  
Purine Nucleotide ◽  
Nucleotide Biosynthesis ◽  
Competitive Fitness ◽  
Guanosine Tetraphosphate ◽  
Growth Recovery ◽  
Physiological Relevance ◽  
And Function

Abstract The alarmone nucleotides guanosine tetraphosphate and pentaphosphate, commonly referred to as (p)ppGpp, regulate bacterial responses to nutritional and other stresses. There is evidence for potential existence of a third alarmone, guanosine-5′-monophosphate-3′-diphosphate (pGpp), with less-clear functions. Here, we demonstrate the presence of pGpp in bacterial cells, and perform a comprehensive screening to identify proteins that interact respectively with pGpp, ppGpp and pppGpp in Bacillus species. Both ppGpp and pppGpp interact with proteins involved in inhibition of purine nucleotide biosynthesis and with GTPases that control ribosome assembly or activity. By contrast, pGpp interacts with purine biosynthesis proteins but not with the GTPases. In addition, we show that hydrolase NahA (also known as YvcI) efficiently produces pGpp by hydrolyzing (p)ppGpp, thus modulating alarmone composition and function. Deletion of nahA leads to reduction of pGpp levels, increased (p)ppGpp levels, slower growth recovery from nutrient downshift, and loss of competitive fitness. Our results support the existence and physiological relevance of pGpp as a third alarmone, with functions that can be distinct from those of (p)ppGpp.

Regulation of purine nucleotide biosynthesis: in yeast and beyond

2006 ◽  
Vol 34 (5) ◽  
pp. 786-790 ◽  
Author(s):  
R.J. Rolfes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
De Novo ◽  
Purine Nucleotide ◽  
De Novo Synthesis ◽  
Normal Functioning ◽  
Purine Nucleotides ◽  
Yeast Saccharomyces Cerevisiae ◽  
Nucleotide Biosynthesis ◽  
Salvage Pathways ◽  
Pool Sizes

Purine nucleotides are critically important for the normal functioning of cells due to their myriad of activities. It is important for cells to maintain a balance in the pool sizes of the adenine-containing and guanine-containing nucleotides, which occurs by a combination of de novo synthesis and salvage pathways that interconvert the purine nucleotides. This review describes the mechanism for regulation of the biosynthetic genes in the yeast Saccharomyces cerevisiae and compares this mechanism with that described in several microbial species.

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