Document Detail

Differential Activation of Ammonium Transporters During the Accumulation of Ammonia by Colletotrichum gloeosporioides and Its Effect on Appressoria Formation and Pathogenicity.
MedLine Citation:
PMID:  23387470     Owner:  NLM     Status:  In-Data-Review    
Ammonium secreted by the post-harvest pathogen Colletotrichum gloeosporioides during host colonization accumulates in the host environment due to enhanced fungal nitrogen metabolism. Two types of ammonium transporter-encoding genes, AMET and MEP, are expressed during pathogenicity. Gene disruption of AMET, a gene modulating ammonia secretion, showed twofold reduced ammonia secretion and 45% less colonization on avocado fruit, suggesting a contribution to pathogenicity. MEPB, a gene modulating ammonium transport, is expressed by C. gloeosporioides during pathogenicity and starvation conditions in culture. Gene disruption of MEPB, the most highly expressed gene of the MEP family, resulted in twofold overexpression of MEPA and MEPC but reduced colonization, suggesting MEPB expression's contribution to pathogenicity. Analysis of internal and external ammonia accumulation by ΔmepB strains in mycelia and germinated spores showed rapid uptake and accumulation, and reduced secretion of ammonia in the mutant versus wild-type (WT) strains. Ammonia uptake by the WT germinating spores but not by the ΔmepB strain with compromised ammonium transport activated cAMP and transcription of PKA subunits PKAR and PKA2. ΔmepB mutants showed 75% less appressorium formation and colonization than the WT, which was partially restored by 10 mM exogenous ammonia. Thus, whereas both AMET and MEPB genes modulate ammonia secretion, only MEPB contributes to ammonia accumulation by mycelia and germinating spores that activate the cAMP pathways, inducing the morphogenetic processes contributing to C. gloeosporioides pathogenicity.
Chen Shnaiderman; Itay Miyara; Ilana Kobiler; Amir Sherman; Dov Prusky
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Molecular plant-microbe interactions : MPMI     Volume:  26     ISSN:  0894-0282     ISO Abbreviation:  Mol. Plant Microbe Interact.     Publication Date:  2013 Mar 
Date Detail:
Created Date:  2013-02-07     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9107902     Medline TA:  Mol Plant Microbe Interact     Country:  United States    
Other Details:
Languages:  eng     Pagination:  345-55     Citation Subset:  IM    
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