Seven of eight species in Nicotiana section Suaveolentes have common factors leading to hybrid lethality in crosses with Nicotiana tabacum

Abstract

Seven of eight wild species produced inviable hybrids after crossing. Hybrid lethality, which was observed in all crosses at 28 degrees C, was Type II lethality, with the characteristic symptoms of browning of hypocotyl and roots; lethality was suppressed at elevated temperatures (34 or 36 degrees C). Furthermore, one or more genes on the Q chromosome of N. tabacum were absolutely responsible for hybrid lethality, suggesting that many species of section Suaveolentes share the same factor that triggers hybrid lethality by interaction with the genes on the Q chromosome. Exceptionally, only one wild species, N. fragrans, produced 100 % viable hybrids after crossing with N. tabacum, suggesting that N. fragrans has no factor triggering hybrid lethality.

Nicotiana debneyi has a single dominant gene causing hybrid lethality in crosses with N. tabacum

“…Hybrid lethality is a type of reproductive isolation mechanism that has been observed in several plant species, including Nicotiana species (Tezuka et al 2010;Yamada et al 1999), rice (Kuboyama et al 2009), wheat (Mizuno et al 2010), cotton (Song et al 2009), and Arabidopsis thaliana (Bomblies et al 2007). This mechanism often causes the death of hybrid plants and can be a barrier for the introduction of desirable genes into cultivated species by wide hybridization.…”

“…In the genus Nicotiana, which is a commercially important member of the family Solanaceae, many attempts at interspecific hybridization have been made, with several of the cross combinations resulting in hybrids displaying abnormal growth and even death (Tezuka et al 2010;Yamada et al 1999). Hybrid lethality in Nicotiana species is classified into the following four types based on surface symptoms: Type I, browning of the shoot apex and root tip; Type II, browning of the hypocotyl and roots; Type III, yellowing of true leaves; and Type IV, formation of multiple shoots (Yamada et al 1999).…”

“…debneyi, N. excelsior, N. goodspeedii, N. gossei, N. maritima, N. megalosiphon, N. suaveolens, and N. velutina, which produce inviable hybrid seedlings exhibiting Type II lethality after reciprocal crosses with cultivated tobacco, N. tabacum. This indicates that hybrid lethality occurs due to interaction of the nuclear genomes of N. tabacum and the wild species, and that cytoplasmic factors are not involved Marubashi 2004, 2006a, b;Tezuka et al 2010). When these nine wild species were crossed with the N. tabacum monosomic lines, Haplo-Q and/or F 1 progeny derived from the cross Haplo-Q 9 N. tabacum 'Samsun NN', which only have one Q chromosome, two types of hybrid plants were obtained: viable hybrid plants lacking Q chromosomes and inviable hybrid plants possessing Q chromosomes.…”

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

“…The shape of the hybrid plants of this cross are nonuniform, unlike crosses of wild species (section Suaveolentes)×N. tabacum (Tezuka et al 2010).…”

Production and characterization of amphihaploid hybrids between Nicotiana wuttkei Clarkson et Symon and N. tabacum L

“…This is defined as ''type II lethality'' according to Yamada et al (1999). Such phenomenon is frequent in the Nicotianas and is characteristic, among others, of reciprocal crosses between N. tabacum and many species from section Suaveolentes (Tezuka et al 2010). In vitro culture allowed production of viable N. wuttkei 9 N. tabacum hybrids, albeit with a low success rate.…”