Identification of Nicotiana tabacum linkage group corresponding to the Q chromosome gene(s) involved in hybrid lethality.
BACKGROUND
A linkage map consisting of 24 linkage groups has been constructed using simple sequence repeat (SSR) markers in Nicotiana tabacum. However, chromosomal assignments of all linkage groups have not yet been made. The Q chromosome in N. tabacum encodes a gene or genes triggering hybrid lethality, a phenomenon that causes death of hybrids derived from some crosses.


RESULTS
We identified a linkage group corresponding to the Q chromosome using an interspecific cross between an N. tabacum monosomic line lacking the Q chromosome and N. africana. N. ingulba yielded inviable hybrids after crossing with N. tabacum. SSR markers on the identified linkage group were used to analyze hybrid lethality in this cross. The results implied that one or more genes on the Q chromosome are responsible for hybrid lethality in this cross. Furthermore, the gene(s) responsible for hybrid lethality in the cross N. tabacum × N. africana appear to be on the region of the Q chromosome to which SSR markers PT30342 and PT30365 map.


CONCLUSIONS
Linkage group 11 corresponded to the Q chromosome. We propose a new method to correlate linkage groups with chromosomes in N. tabacum.
Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, Japan. tezuka@plant.osakafu-u.ac.jp
Takahiro
T
Tezuka
Chihiro
C
Matsuo
Takahiro
T
Iizuka
Masayuki
M
Oda
Wataru
W
Marubashi
D032461:Chromosomes, Plant; D003433:Crosses, Genetic; D008040:Genetic Linkage; D006824:Hybridization, Genetic; D014026:Nicotiana / Q000235:genetics*