Karyotype and genome size comparative analyses among six species of the oilseed-bearing genus Jatropha (Euphorbiaceae)

Abstract

Jatropha is an important genus of Euphorbiaceae, with species largely used for various purposes, including the manufacturing of soaps and pharmaceutical products and applications in the bioenergetic industry. Although there have been several studies focusing J. curcas in various aspects, the karyotype features of Jatropha species are poorly known. Therefore, we analyzed six Jatropha species through fluorochrome staining (CMA/DAPI), fluorescent in situ hybridization (FISH) with 5S and 45S rDNA probes and genome size estimation by flow cytometry. Our results revealed several chromosome markers by both CMA/DAPI and FISH for the analyzed species. Five Jatropha species (J. curcas, J. gossypiifolia, J. integerrima, J. multifida and J. podagrica) showed four CMA-positive (CMA+) bands associated with the 5S and 45S rDNA sites (one and two pairs, respectively). However, J. mollissima displayed six CMA+/DAPI- bands co-localized with both 5S and 45S rDNA, which showed a FISH superposition. A gradual variation in the genome sizes was observed (2C = 0.64 to 0.86 pg), although an association between evidenced heterochromatin and genome sizes was not found among species. Except for the unique banding pattern of J. mollissima and the pericentromeric heterochromatin of J. curcas and J. podagrica, our data evidenced relatively conserved karyotypes.

Genome composition and pollen viability of Jatropha (Euphorbiaceae) interspecific hybrids by Genomic In Situ Hybridization (GISH)

“…However, GISH pattern for Jatropha chromosomes appears mainly at pericentromeric region, probably due to their heterochromatic proximal condensation pattern (Fukuhara et al, 2016), in accordance to the CMA + (Chromomycin A3) heterochromatin distribution for J. curcas chromosomes, for instance (Marinho et al, 2018), indicating the preferential GISH for heterochromatic regions. The pericentromeric heterochromatin in J. curcas is constituted in part by Gypsy-type retrotransposon (Alipour et al, 2014).…”

“…The pericentromeric heterochromatin in J. curcas is constituted in part by Gypsy-type retrotransposon (Alipour et al, 2014). On the other hand, in J. integerrima and in J. multifida species, the heterochromatic CMA + pattern is restricted to 35S rDNA sites (Marinho et al, 2018). Additionally, terminal dots in J. curcas probably correspond to JcSat1 J. curcas satellite DNA sequence (Fukuhara et al, 2016) or to Copia-type elements as described previously (Alipour et al, 2013).…”

“…Additionally, J. integerrima presents biotic stress tolerance, with maximum resistance against foliage feeders in terms of larval mortality, besides feeding cessation with or without pupation (Sujatha, 2013). On the other hand, the also diploid J. multifida (2n = 2x = 22, Marinho et al, 2018) presents seeds about 30% larger and with a higher oil content (50%) than J. curcas (23-38%) (Sujatha, 1996;Banerji et al, 1985). The energetic value of J. multifida oil (57.1 MJ/kg) is the highest among the studied Jatropha species, surpassing values observed for J. glandulifera Roxb.…”

“…Jatropha curcas is a monoecious species with unisexual flowers (Montes and Melchinger, 2016); xenogamic (Divakara et al, 2010;de Argollo Marques et al, 2013); self-compatible (Chang-Wei et al, 2007;Brasileiro et al, 2012), and diploid (2n = 2x = 22), as well as most congeners species (Carvalho et al, 2008;Sasikala and Paramathma, 2010;Marinho et al, 2018). These traits allow crosses between Jatropha species, although with limited success due to either pre-or post-zygotic barriers (Moreira et al, 2013), which can be overcome using in vitro embryo rescue technique (Laosatit et al, 2017).…”

Heterochromatin and numeric chromosome evolution in Bignoniaceae, with emphasis on the Neotropical clade Tabebuia alliance

“…The pattern of two CMA + telomeric bands (chromosome type A) seen in most species of the Tabebuia alliance is very common among Angiosperms, and usually corresponds to a nucleolar organizer region (Guerra, 2000;Roa and Guerra, 2012). Telomeric CMA bands are most likely related to rDNA sites as seen in most plant species (Barros e Silva et al, 2010;Castro et al, 2016;Marinho et al, 2018). Differences among species could be related tochromosome rearrangements and the amplification and reduction of rDNA sites caused by satellites or transposable sequences (Mehrotra and Goyal, 2014;Evtushenko et al, 2016;Saze, 2018).…”