Possible involvement of genes on the Q chromosome of Nicotiana tabacum in expression of hybrid lethality and programmed cell death during interspecific hybridization to Nicotiana debneyi.
Hybrid seedlings from the cross between Nicotiana tabacum, an allotetraploid composed of S and T subgenomes, and N. debneyi die at the cotyledonary stage. This lethality involves programmed cell death (PCD). We carried out reciprocal crosses between the two progenitors of N. tabacum, N. sylvestris and N. tomentosiformis, and N. debneyi to reveal whether only the S subgenome in N. tabacum is related to hybrid lethality. Hybrid seedlings from reciprocal crosses between N. sylvestris and N. debneyi showed lethal characteristics identical to those from the cross between N. tabacum and N. debneyi. Conversely, hybrid seedlings from reciprocal crosses between N. tomentosiformis and N. debneyi were viable. Furthermore, hallmarks of PCD were observed in hybrid seedlings from the cross N. debneyi x N. sylvestris, but not in hybrid seedlings from the cross N. debneyi x N. tomentosiformis. We also carried out crosses between monosomic lines of N. tabacum lacking the Q chromosome and N. debneyi. Using Q-chromosome-specific DNA markers, hybrid seedlings were divided into two groups, hybrids possessing the Q chromosome and hybrids lacking the Q chromosome. Hybrids possessing the Q chromosome died with characteristics of PCD. However, hybrids lacking the Q chromosome were viable and PCD did not occur. From these results, we concluded that the Q chromosome belonging to the S subgenome of N. tabacum encodes gene(s) leading to hybrid lethality in the cross N. tabacum x N. debneyi.
Tezuka
Takahiro
T
School of Agriculture, Ibaraki University, Ami, Ibaraki 300-0393, Japan.
Kuboyama
Tsutomu
T
Matsuda
Toshiaki
T
Marubashi
Wataru
W
D017209:Apoptosis; D019070:Cell Lineage; D002467:Cell Nucleus / Q000378:metabolism; D032461:Chromosomes, Plant / Q000235:genetics*; D003433:Crosses, Genetic; D053938:DNA Fragmentation; D017343:Genes, Plant; D006824:Hybridization, Genetic; D011058:Pollen / Q000502:physiology; D019105:Random Amplified Polymorphic DNA Technique; D036226:Seedlings / Q000378:metabolism; D013045:Species Specificity; D013696:Temperature; D014026:Nicotiana / Q000166:cytology* / Q000235:genetics*