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| Title: An autophagy gene , MgATG5 , is required for cell differentiation and pathogenesis in Magnaporthe oryzae .
| | Author: Lu JP Liu XH Feng XX Min H Lin FC | | Journal: Curr Genet Citation: V : 55 P : 461-73 Year: 2009 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub19629489 Accession (PMID): 19629489 | | Abstract: Autophagy is a conserved degradation pathway that is involved in the maintenance of normal cell differentiation and development .
The Saccharomyces cerevisiae ATG5 gene is an important component of the autophagy process .
In this study , we identified MgATG5 as an autophagy-related gene in Magnaporthe oryzae that is homologous to ATG5 .
Using targeted gene replacement , an Mgatg5Delta mutant was generated and fungal autophagy was blocked .
Cytological analysis revealed that the mutant had poor fungal morphogenic development , including a shortened aerial hyphae lifespan , decreased conidiation and perithecia formation , delayed conidial germination and appressorial formation , postponement of conidial cytoplasm transfer during appressorium formation , and reduction in formation of the penetration peg .
Turnover of endogenous matter in the Mgatg5 mutant was also affected , as demonstrated by defects in the formation of conidial lipid droplets , and in the degradation of conidial glycogen deposits during appressorium formation .
Lipid droplets and glycogen are necessary to generate adequate turgor in appressoria for invading the host surface .
As a result of the decreased appressorium turgor and differentiation in the penetration peg , Mgatg5Delta pathogenicity was deficient in two host plants tested .
The developmental and pathogenic phenotypes were restored by the introduction of an intact copy of MgATG5 into Mgatg5Delta , demonstrating that the MgATG5 deletion was responsible for the cellular defects .
Taken together , these findings suggest that autophagy promotes cell differentiation through turnover of endogenous matter during fungal development , and is thus essential for the pathogenicity of the rice blast fungus .
| Matching Sentences:
[ Sen. 2, subscore: 1.00 ]: The Saccharomyces cerevisiae ATG5 gene is an important component of the autophagy process .
[ Sen. 3, subscore: 1.00 ]: In this study , we identified MgATG5 as an autophagy-related gene in Magnaporthe oryzae that is homologous to ATG5 .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
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| Title: The ATG autophagic conjugation system in maize : ATG transcripts and abundance of the ATG8-lipid adduct are regulated by development and nutrient availability .
| | Author: Chung T Suttangkakul A Vierstra RD | | Journal: Plant Physiol Citation: V : 149 P : 220-34 Year: 2009 Type: MEDLINE | | Literature: oryza Field: abstract Doc ID: pub18790996 Accession (PMID): 18790996 | | Abstract: Plants employ sophisticated mechanisms to recycle intracellular constituents needed for growth , development , and survival under nutrient-limiting conditions .
Autophagy is one important route in which cytoplasm and organelles are sequestered in bulk into vesicles and subsequently delivered to the vacuole for breakdown by resident hydrolases .
The formation and trafficking of autophagic vesicles are directed in part by associated conjugation cascades that couple the AUTOPHAGY-RELATED8 ( ATG8 ) and ATG12 proteins to their respective targets , phosphatidylethanolamine and the ATG5 protein .
To help understand the importance of autophagy to nutrient remobilization in cereals , we describe here the ATG8/12 conjugation cascades in maize ( Zea mays ) and examine their dynamics during development , leaf senescence , and nitrogen and fixed-carbon starvation .
From searches of the maize genomic sequence using Arabidopsis ( Arabidopsis thaliana ) and rice ( Oryza sativa ) counterparts as queries , we identified orthologous loci encoding all components necessary for ATG8/12 conjugation , including a five-member gene family expressing ATG8 .
Alternative splicing was evident for almost all Atg transcripts , which could have important regulatory consequences .
In addition to free ATG8 , its membrane-associated , lipidated form was detected in many maize it issues , suggesting that its conjugation cascade is active throughout the plant at most , if not all , developmental stages .
Levels of Atg transcripts and/or the ATG8-phosphatidylethanolamine adduct increase during leaf senescence and nitrogen and fixed-carbon limitations , indicating that autophagy plays a key role in nutrient remobilization .
The description of the maize ATG system now provides a battery of molecular and biochemical tools to study autophagy in this crop under field conditions .
| Matching Sentences:
[ Sen. 3, subscore: 1.00 ]: The formation and trafficking of autophagic vesicles are directed in part by associated conjugation cascades that couple the AUTOPHAGY-RELATED8 ( ATG8 ) and ATG12 proteins to their respective targets , phosphatidylethanolamine and the ATG5 protein .
| | Supplemental links/files: reference in endnote online text related articles pubmed citation | |
