Polyploidy and the relationship between leaf structure and function: implications for correlated evolution of anatomy, morphology, and physiology in Brassica

BMC Plant Biology

Research Article

Katherine Vidal¹  Brent E. Ewers¹  Robert L. Baker¹  Cynthia Weinig²  Yulia Yarkhunova³ 

[1] Department of Botany, University of Wyoming, 82071, Laramie, WY, USA;Department of Botany, University of Wyoming, 82071, Laramie, WY, USA;Department of Molecular Biology, University of Wyoming, 82071, Laramie, WY, USA;Department of Botany, University of Wyoming, 82071, Laramie, WY, USA;Program in Ecology, University of Wyoming, 82071, Laramie, WY, USA;

关键词: Brassica;    Polyploidy;    Phenotypic integration;    Leaf morphology;    Leaf anatomy;    Leaf physiology;    Triangle of U, Hybridization;    Whole genome duplication;   

DOI  :  10.1186/s12870-016-0957-3

 received in 2016-08-23, accepted in 2016-12-19,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundPolyploidy is well studied from a genetic and genomic perspective, but the morphological, anatomical, and physiological consequences of polyploidy remain relatively uncharacterized. Whether these potential changes bear on functional integration or are idiosyncratic remains an open question. Repeated allotetraploid events and multiple genomic combinations as well as overlapping targets of artificial selection make the Brassica triangle an excellent system for exploring variation in the connection between plant structure (anatomy and morphology) and function (physiology). We examine phenotypic integration among structural aspects of leaves including external morphology and internal anatomy with leaf-level physiology among several species of Brassica. We compare diploid and allotetraploid species to ascertain patterns of phenotypic correlations among structural and functional traits and test the hypothesis that allotetraploidy results in trait disintegration allowing for transgressive phenotypes and additional evolutionary and crop improvement potential.ResultsAmong six Brassica species, we found significant effects of species and ploidy level for morphological, anatomical and physiological traits. We identified three suites of intercorrelated traits in both diploid parents and allotetraploids: Morphological traits (such as leaf area and perimeter) anatomic traits (including ab- and ad- axial epidermis) and aspects of physiology. In general, there were more correlations between structural and functional traits for allotetraploid hybrids than diploid parents. Parents and hybrids did not have any significant structure-function correlations in common. Of particular note, there were no significant correlations between morphological structure and physiological function in the diploid parents. Increased phenotypic integration in the allotetraploid hybrids may be due, in part, to increased trait ranges or simply different structure-function relationships.ConclusionsGenomic and chromosomal instability in early generation allotetraploids may allow Brassica species to explore new trait space and potentially reach higher adaptive peaks than their progenitor species could, despite temporary fitness costs associated with unstable genomes. The trait correlations that disappear after hybridization as well as the novel trait correlations observed in allotetraploid hybrids may represent relatively evolutionarily labile associations and therefore could be ideal targets for artificial selection and crop improvement.

【 授权许可】

CC BY   
© The Author(s). 2017