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

Abstract

Allopolyploids are known to have superior advantages such as high growth speed. Triploids have even greater heterozygosity, explaining more phenotypic variance than 2n hybrid F1 and have therefore become new resources in breeding. To date, the metabolomic basis underlying polyploidization vigor remains unclear. Here, we identified and compared 235 metabolites in the shoot apical buds between multiple allo-triploid populations and parental 2n hybrid F1 in Populus via metabolome profiling using liquid chromatography-mass spectrometry (LC-MS) assays. Associations with growth vigor in three types of allo-triploid populations, namely first division restitution (FDR), second division restitution (SDR) and postmeiotic restitution (PMR) generated from doubled 2n female gametes and male gametes of 2n hybrid, were also investigated. Each allo-triploid population has different sub-genome duplicated. Major metabolomes were amino acids, secondary metabolism associated, and carbohydrates. We mapped 181 metabolites into known metabolism pathways in the Kyoto Encyclopedia of Genes and Genomes (KEGG). Ten compounds, i.e., fructose 1,6-diphosphate and xylulose, were more abundant in all allo-triploids than the 2n hybrid. Principal component analysis revealed the abundance of metabolites fell into distinct clusters corresponding to ploidy composition. Heterozygosity in triploids mainly effected the contents of carbohydrates and secondary metabolites rather than lipids. Comparisons between subgroups with different growth rates revealed some carbohydrates and secondary metabolites of flavonoids were positively associated with gene expression and the high growth vigor. The results provided an informative metabolomic basis for factors conferring growth vigor in polyploid Populus. IntroductionPolyploid organisms have more than two sets of chromosomes; 30-80% of plant kingdom are polyploid. Many plant lineages show evidence of palaeopolyploidization in their genomes. Polyploid plants usually have larger cell size and faster growth, which are both agronomically preferred traits [1]. Polyploid breeding in plants, including synthesized polyploidization, has increased the rate of breeding in many crops and also in trees, such as Populus [2][3][4][5]. Polyploidization leads to a series of genomic, metabolomic, cellular and physiological changes. Typically, a reduction in genome size occurs after polyploidization, followed by neo-functionalization, sub-functionalization and gene product dosage balance, gene rearrangement, and epigenetic modification, which all drive the evolution and speciation [6]. Cell size is usually increased in polyploid plants likely due to a delayed cell division [5].

The chemotype core collection of genus Nicotiana

“…This indicates that a range of changes associated with hybridisation occurred (e.g. altered transcriptional processes, stoichiometries of regulatory factors, interaction of duplicated genes and subgenome intermixing) and influenced the chemical composition of the alloploid progeny (Cheng et al., 2019; Daniell et al., 2016; Nieto Feliner et al., 2020; Schoenfelder & Fox, 2015).…”

Allotetraploidization in Brachypodium May Have Led to the Dominance of One Parent’s Metabolome in Germinating Seeds

“…Many plant lineages show evidence of palaeopolyploidization in their genomes. Polyploid plants usually have larger cell sizes and faster growth, which is very significant from an evolutionary standpoint [ 1 , 2 ]. Polyploidization leads to a series of genomic, metabolomic, cellular, and physiological changes.…”

Características morfológicas y producción de aloína de plantas poliploides de Aloe vera (L.) Burm. F. (Asphodelaceae)

“…Una de las aplicaciones de la técnica de inducción de poliploidía en plantas, es lograr el aumento de la biomasa y la cantidad de metabolitos secundarios. Ejemplo de ello son los casos de las plantas de Artemisia annua (De Jesús y Weathers, 2003; Zanmaria, 2016), Taxus chinensis (Li et al, 2008) Citrus reticulata (Tan et al., 2019) e híbridos del género Populus (Cheng et al, 2019) en las cuales lograron obtener en algunos casos tetraploides y en otros triploides, con aumento de las cantidades de artemisina, taxol, ácido ascórbico y flavonoides, respectivamente, que son los metabolitos secundarios más conocidos en estas especies. En Valeriana wallichii se generó la producción de nuevos compuestos en las plantas, ausentes en sus Volumen 33 (2021) BIOAGRO N° 1…”