The effect of different genome and cytoplasm on meiotic pairing in maize newly synthetic polyploids

Abstract

Allopolyploidization plays the special role in the evolution of many crops. Moreover, the evolution in early stage of some allopolyploidization events is predicted to be effected by nuclear-cytoplasmic interactions. Maize and teosintes are well model system for study of genetic recombination in allopolyploidization. In order to investigate the effects of genome organization and cytoplasm on genome evolution in newly synthesized allopolyploids (neoallopolyploids), a series of neoallopolyploids were produced by reciprocal crosses of maize and Zea perennis. By using dual-color genomic in situ hybridization, intra-and intergenomic meiosis pairing of these polyploids were quantified and compared with regard to its genome organization and cytoplasm background. In the four neoallopolyploids, the stability of maize genome is consistently lower than that of Z. perennis genome. Additional, the stability of maize genome is affected by genome ploidy. The cytoplasm, genome composition and their interaction do have the special role in chromosome paring and the meiosis behaviors in Zea allopolyploids vary significantly and showed non-diploidization. Z. perennis cytoplasm may give a relatively relaxed environment for maize genome.

Analysis of the genitor origin of an intergeneric hybrid clone between <i>Zea</i> and <i>Tripsacum</i> for forage production by McGISH

“…This is not a surprising result owing to allosyndesis between the chromosomes of maize and Z. perennis in MTP (Iqbal et al 2019). Such chromosomal translocation between the maize chromosomes and those of Z. perennis has occurred in the previous maize × Z. perennis hybrids (Cheng et al 2016, Iqbal et al 2018.…”

“…For example, McGISH was successfully used to confirm the hybrid status and chromosome translocation in the maize-Z. perennis hybrids (Cheng et al 2016, Iqbal et al 2018 and the maize-T. dactyloides-Z. perennis hybrids (Iqbal et al 2019, Li et al 2015.…”

Allopolyploidization facilitates gene flow and speciation among corn, Zea perennis and Tripsacum dactyloides

“…The cross between colchicine-treated tetraploid maize (2n = 4x = 40)and Z. perennis (2n = 4x = 40) could give rise to allotetraploid F1 (2n = 4x = 40) that showed normal meiosis and higher pollen viability (Shaver 1964). Previous studies have confirmed that five chromosomes from "A" genome of maize shared higher homology with 10 chromosomes from Z. perennis (Schnable et al 2011;Cheng et al 2016).…”

“…The genetic bridges (usage of a third parent in between two parents) can break crossing barriers in between divergent species (Hussain and Williams 1997;Reagon and Snow 2006) and choice of small DNA fragments (translocations) can be advantageous to get rid of unwanted traits. Polyploid provides an effective bridge for a controlled induction of alien genes into cultivated crops and the choice of an allopolyploid bridge plant is preferable due to its genome plasticity (Stebbins 1971;Cheng et al 2016), gene redundancy, asexual reproduction (Comai 2005) and allopolyploid's capability to seldom disrupt selfincompatibility barriers (Miller and Venable 2000). Polyploidy and distinct hybridization have already enriched the genetic background of important agricultural crops (Hajjar and Hodgkin 2007), for example wheat (Jiang et al 2017), rice (Shakiba and Eizenga 2014;Ramos et al 2016), maize (Maazou et al 2017), Brassica (Li et al 2014) and tobacco (Hancock and Lewis 2017).…”

“…Natural gene flow between diploid maize and Z. perennis is tremendously low, if of any kind (Doebley 1990). However, artificial hybridization is possible (Tang et al 2005) but the triploid nature of F1 hybrids (2n = 3x = 30) makes them sterile (Shaver 1964;Cheng et al 2016). The cross between colchicine-treated tetraploid maize (2n = 4x = 40)and Z. perennis (2n = 4x = 40) could give rise to allotetraploid F1 (2n = 4x = 40) that showed normal meiosis and higher pollen viability (Shaver 1964).…”