1991 Fiscal Year Final Research Report Summary
Studies on Genetic Relationships in Plant Pathogenic Fungi based on DNA Analysis.
| Project/Area Number |
01560056
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
植物保護
|
|---|
| Research Institution | Higashi Nippon Gakuen University |
|---|
Principal Investigator |
KUNINAGA Shiro Higashi Nippon Gakuen University, Department of General Education, Lecturer, 教養部, 講師 (20094831)
|
|---|
| Project Period (FY) |
1989 – 1991
|
| Keywords | Fusarium oxysporum / Rhizoctonia solani / DNA homology / Mitochondrial DNA / Chromosomal DNA / Pulsed-field gel electrophoresis / Restriction fragment length polymorphisms / Chemical taxonomy |
|---|
| Research Abstract |
The genetic relatioships among subspecies (formae speciales and races) within Fusarium oxysporum (F. -o.), and among anastomosis groups 9 (AG-9) within. Rhizoctonia solani. (R. S.) were determined on the basis of DNA-DNA reassociation kinetics, restriction fragment length polymorphisms (RFLPS) of mitochondrial DNA (mtDNA) and pulsed-field gel electrophoresis- (PFG&) of chromosomes.
1. Genetic relatedness among 18 formae speciales within F. o. DNA homology values were high (more than 95%) between isolates within the same formae speciales, while isolates of different formae speciales showed lower values (63 to 86%) of DNA homology. The reassociation analysis of DNA may be a useful tool in studies involving classification of subspecific taxa in this species. The studies also suggest that the causal fungi-of tomato crown and root-rot in Japan, previously proposed as race J3 of f. sp. lycopersici, should be designated as a different formae speciales : F. o. f. sp. radicis-lycopersici.
2. The
… More
subgroups (TP : thiamine prototrophic isolates, and TX : thiamine auxotrophic isolates within AG-9 of R. s. can be distinguished from one another by the reassociation analysis of DNA. DNA homology values among isolates belonging within either group is 94% or higher, whereas the values among TP and TX ranges from 78-87%.
3. RFLPs of mtDNA were employed to estimate genetic diversity in F. o. f. sp. lycopersici. Digestion with eight restriction endonudeases revealed three types of mtDNA (ntDNAtype I, type IIa and type IIb). These types corresponded to each of three vegetative compatibility groups (VCGs), whereas races could not be distinguished by comparison of Rflps. It is suggested that mtDNA RFLPs can be used to define genetic diversity among population within F. o. f. sp.
lycopersici.
4. Isolates of F. o. f. sp. lycopersici were found to have distinct electrophoretic karyotypes on the basis of PFGE>The fungi had six to eight chromosomes (900-6, 000kb). Extensive polymorphisms for chromosomes of less than 3, 000kb were observed. No significant relatioships were obtained between races and the polymorphisms for chromosomal length and number. Further studies to characterize the electrophoretic karyotypes of this species will be needed. Less
|
