Hybrid lethality with programmed cell death results from reciprocal interspecific crosses between Nicotiana nudicaulis Watson and N. tabacum L.

Abstract

Hybrid seedlings from reciprocal interspecific crosses between Nicotiana nudicaulis and N. tabacum were not viable when cultured at 28°C; this an example of hybrid lethality. Characteristically, shoot apices and root tips of these hybrids began to brown immediately after germination at 28°C. However, hybrid seedlings did not exhibit any symptoms of lethality at 34°C, and their growth was normal at this higher temperature. When hybrid seedlings were cultured at 34°C and then transferred to 28°C, lethal symptoms emerged rapidly after the transfer. Therefore, hybrid lethality associated with reciprocal interspecific crosses between N. nudicaulis and N. tabacum was due to the interaction of coexisting heterologous genomes and not to a cytoplasmic effect. Furthermore, as the N. nudicaulis×N. tabacum seedlings die, features of apoptotic cell death, including chromatin condensation, nuclear fragmentation, and fragmentation of DNA, were evident. These observations indicated that hybrid lethality of N. nudicaulis×N. tabacum seedlings is accompanied by apoptotic cell death. This report is the first to demonstrate that hybrid lethality with apoptotic cell death results from N. nudicaulis×N. tabacum hybridization.

Development of a Method to Produce Chromosome Lacking Lines (CLLs) in <i>Nicotiana tabacum</i> L. “Red Russian”

“…When N. nudicaulis Watson, belonging to the section Repandae [11] [15], is crossed with N. tabacum, hybrid seedlings show lethal symptoms [1] [16], which are controlled by the S subgenome of N. tabacum [17]. However, this hybrid lethality is different from that expressed in crosses between section Suaveolentes and N. tabacum, whose lethality is not related to the Q chromosome [17].…”

Identification of genomic factors responsible for hybrid lethality in hybrids between Nicotiana nudicaulis Watson and N. tabacum L.

“…nudicaulis were transferred to flat-bottomed test tubes that contained 10 ml of 1/2 MS medium supplemented with 1% sucrose and 0.25% Gelrite, pH 5.8, and cultured at 28°C, 34°C, or 36°C. In a previous report (Liu et al 2013), the desired results were obtained in a cross of N. nudicaulis×N. tabacum at 34°C.…”

“…In reciprocal interspecific crosses between N. nudicaulis and N. tabacum, hybrid lethality was observed at 28°C, but not at 34°C (Yamada et al 1999;Liu et al 2013). In this study, we crossed N. nudicaulis with two progenitors of N. tabacum, N. sylvestris (SS) and N. tomentosiformis (TT), to reveal which subgenome of N. tabacum contains the genomic factors responsible for hybrid lethality in hybrids between N. nudicaulis and N. tabacum.…”

Species Origin of Genomic Factors in Nicotiana nudicaulis Watson Controlling Hybrid Lethality in Interspecific Hybrids between N. nudicaulis Watson and N. tabacum L

“…In hybrid seedlings of N. nudicaulis × N. tabacum expressing hybrid lethality, features of apoptosis such as chromatin condensation, nuclear fragmentation, and fragmentation of DNA were evident [38].…”

“…Furthermore, Kobori and Marubashi [37] concluded that the T subgenome of N. tabacum encodes the causative gene(s) for hybrid lethality in the cross N. repanda × N. tabacum . On the other hand, the S subgenome of N. tabacum is related to hybrid lethality at 28°C in hybrids between N. nudicaulis and N. tabacum [38] , [39] . In contrast to research on the subgenome controlling hybrid lethality in N. tabacum , no studies of the subgenome of wild species involved in hybrid lethality have been reported to our knowledge.…”