Transcriptomic changes following synthesis of a Populus full-sib diploid and allotriploid population with different heterozygosities driven by three types of 2n female gamete

Abstract

Diploid gametes are usually applied to produce triploids of Populus [originating from first-division restitution (FDR), second-division restitution (SDR), and postmeiotic restitution (PMR) 2n eggs]. Three types of 2n gametes transmitted different parental heterozygosities in Populus. Failed spindle formation and no chromosomal separation to opposite poles during meiosis I mean that FDR 2n gametes carry nonsister chromatids that are potentially heterozygous. By contrast, SDR 2n gametes result from failed sister chromatid separation in meiosis II, and therefore, they carry sister chromatid that are potentially homozygous. Completely homozygous 2n gametes can arise from the PMR mechanism. The alteration of gene expression resulting from allopolyploidization is a prominent feature in plants. We compared gene expression in the full-sib progeny of three allotriploid Populus populations (triploid-F, triploid-S, and triploid-P) with that in its parent species, and their full-sib diploid F1 hybrid. Genome-wide expression level dominance was biased toward the maternal in the diploid F1 hybrid and three allotriploid populations, whereas our data indicated important, but different, effects of the transmission of different heterozygosity by 2n female gametes in the expression patterns of allopolyploids. Because of the higher level of heterozygosity, the triploids had higher rates of non-additive and transgressive expression patterns in the triploid-F than in triploid-S and triploid-P. Compared with diploid F1, about 30-fold more genes (251) were differently expressed in the triploid-F than in the triploid-S (9) and triploid-P (8), respectively. These findings indicate that hybridization and polyploidization have immediate and distinct effects on the large-scale patterns of gene expression, and different effects on the transmission of heterozygosity by three 2n female gametes.

Megaspore Chromosome Doubling in Eucalyptus urophylla S.T. Blake Induced by Colchicine Treatment to Produce Triploids

“…Afterward, many studies looking at the artificial induction of polyploid began [14,21,46], and many excellent results were obtained in the last 10 years [27][28][29][30][31][32][33]. Previous research has shown that polyploid breeding is more successful upon utilization of heterosis [47][48][49]. To realize the comprehensive utilization of the dosage effect and heterosis in Eucalyptus, a more reasonable process could be to obtain triploids by sexual polyploidization.…”

Sub-Genome Polyploidization Effects on Metabolomic Signatures in Triploid Hybrids of Populus

“…Forests 2019, 10, 1091 3 of 13 'Beijingensis'. Allo-triploids namely FDR, SDR and PMR were previously generated from the 2n hybrid F1 [2,3,13]. Briefly, the FDR population is generated from male gametes and non-reduced egg gametes in which chromosomes do not move to the opposite poles during meiosis I.…”

“…The SDR population is generated from male gametes and non-reduced egg gametes in which no cell plate is formed during sister chromatid separation in meiosis II. The PMR population is generated from male gametes and non-reduced egg gametes in which chromosomes are duplicated after meiosis [2,3,13]. The apical buds were collected from 15 individuals of 2n hybrid F1 Populus, and 15 individuals from each of three allo-triploid populations namely FDR, SDR and PMR, and 15 individuals from their parental progenitors.…”

“…Tissues from a tree individual were pooled as one sample. Tree height was measured as described previously [13] and grouped into high (G, 10% of the tallest), low (D, 10% of the lowest) and mixed group (H) according the average plant height and base diameter. Collected samples were flash frozen in liquid nitrogen and transferred into a −80 • C freezer until subsequent use.…”

“…These triploids have been found to exhibit superiority in growth vigor, stress resistance, photosynthesis and timber quality compared with 2n hybrids [2,12]. Further RNA-Seq based transcriptome analyses in these triploids and 2n hybrids show that levels of differentially expressed genes are mostly additive with only a small proportion being biased or non-additive and transgressive [13].…”