title: AFLP analysis of genetic diversity in charcoal rot fungal populations impacted by crop rotations.
abstract: The application of molecular markers enables scientists to clarify the genetic relationships among fungi who are difficult to classify or partition into sub-species using traditional morphological or physiological criteria. One such fungus is Macrophomina phaseolina, a plant pathogenic soil-borne fungus that is the causative agent of Charcoal Rot on soybeans and 500 other plant species world-wide. This plant pathogenic fungus is a very heterogeneous species and disease population dynamics and pathogen genetic diversity are poorly understood. Using a multi-variant Amplified Fragment Length Polymorphism (AFLP) approach for the analysis of genomic data, valuable insight into cultural and environmental pressures that shape the fungal genome was possible. Fungal isolates from 12-year rotated field plots ranging from 1-3 years of crop rotations of the same plant type(s), rotation duration and plant maturity groups provided a unique opportunity to survey M. phaseolina isolates taken from the different crop rotation conditions. Using different data interval partitioning of amplified restriction fragments it was possible to see trends associated with the specific cropping history of the fungal isolates. AFLP neutral primers of intermediate and large amplified products using 20-bp intervals were the most efficient and reliable for demonstrating intra-population dynamics. Results indicate that the highest amount of M. phaseolina genetic diversity was conclusively found in fungal isolates taken from three-year rotation plots. Lesser amounts of genetic diversity were found in two-year rotated and non-rotated fungal isolates. Insight gained from this study may now be incorporated into a larger understanding of how crop rotation and the availability of hosts shape and influence the genetic variability within Macrophomina isolates and populations. This information can then be used to make better-informed decisions regarding crop protection strategies against this diverse and economically important fungal pathogen.
authors.affiliation: Department of Biology, Pittsburg State University, Pittsburg, Kansas, USA. Nbrooker@pittstate.edu
authors.forename: N
authors.initials: N
authors.lastname: Brooker
authors.forename: J R
authors.initials: JR
authors.lastname: Lord
authors.forename: J
authors.initials: J
authors.lastname: Long
authors.forename: A
authors.initials: A
authors.lastname: Jayawardhana
mesh_terms: D000383:Agriculture / Q000379:methods*; D001203:Ascomycota / Q000145:classification* / Q000235:genetics*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005784:Gene Amplification; D014644:Genetic Variation; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology; D018517:Plant Roots / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000379:methods; D012150:Polymorphism, Restriction Fragment Length; D011157:Population Dynamics; D013025:Glycine max / Q000382:microbiology*
chemical_list: D004269:DNA, Bacterial