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ARS Home » Research » Publications at this Location » Publication #121981
Title: SEGREGATION, AGGRESSIVENESS, AND SEXUALITY IN PHAEOSPHAERIA NODORUM

Author
item Ueng, Peter
item DAI, Q - SHANDONG UNIV CHINA
item CUI, K - LANZHOU UNIV CHINA
item CUNFER, B - UNIV OF GEORGIA
item ARSENIUK, E - POLAND

Submitted to: American Phytopathological Society
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Genetic segregation and recombination of mating type genes, anonymous markers, AFLP-generated fragments and the internal transcribed spacer (ITS) region of rDNA in the ascospore-derived progeny of Phaeosphaeria nodorum were studied by several molecular methods. The mating types can be determined by PCR amplification with two designated primer sets. The mating type genes consistently segregated in the second division of meiosis during ascospore formation. Based on RFLP and AFLP fingerprinting, six segregation patterns of anonymous markers and AFLP-gene Mendelian frequency 4:4. These segregation patterns indicated that nuclear separation occurred in both the first and second divisions of meiosis. However, anonymous markers randomly segregated at either the first or the second division of meiosis in the four sets of crossing. This randomness in segregation could be interpreted as part of recombination and chromosomal rearrangement. Four singly represented regular (4:4) segregations and a number of irregular aberrant segregations were detected by AFLP technique in cross S-80-301 x S-74-20A. recombination during the sexual process in P. nodorum. Different levels of aggressiveness were found in the eight ascospore progeny of cross sn26-1 x sn48-1. High aggressiveness toward wheat and rye in two different parental isolates were segregated and successfully transferred to the progeny. An ascospore-derived culture from this cross, sn64-5, had high aggressiveness toward both host plants was produced. It is concluded that sexual crossing in P. nodorum is responsible for change in host specificity and aggressiveness.