Natural variation identifies multiple loci controlling petal shape and size in Arabidopsis thaliana.

Mary C Abraham,Chanatip Metheetrairut,Vivian F Irish

doi:10.1371/journal.pone.0056743

Abstract

Natural variation in organ morphologies can have adaptive significance and contribute to speciation. However, the underlying allelic differences responsible for variation in organ size and shape remain poorly understood. We have utilized natural phenotypic variation in three Arabidopsis thaliana ecotypes to examine the genetic basis for quantitative variation in petal length, width, area, and shape. We identified 23 loci responsible for such variation, many of which appear to correspond to genes not previously implicated in controlling organ morphology. These analyses also demonstrated that allelic differences at distinct loci can independently affect petal length, width, area or shape, suggesting that these traits behave as independent modules. We also showed that ERECTA (ER), encoding a leucine-rich repeat (LRR) receptor-like serine-threonine kinase, is a major effect locus determining petal shape. Allelic variation at the ER locus was associated with differences in petal cell proliferation and concomitant effects on petal shape. ER has been previously shown to be required for regulating cell division and expansion in other contexts; the ER receptor-like kinase functioning to also control organ-specific proliferation patterns suggests that allelic variation in common signaling components may nonetheless have been a key factor in morphological diversification.

Highlights

Within a species, individuals are remarkably consistent in their shape and size, yet differences in scale are often the most striking observations when comparisons between species are made [1]
Natural Variation in Petal Shape and Size To assess a sample of the range of petal shape and size in Arabidopsis thaliana, we examined 12 different natural isolates representing a broad range of genetic diversity [50](Figure S1 & S2)
We demonstrated that the genetic control of different parameters, such as petal length and width, can be uncoupled

Summary

Introduction

Individuals are remarkably consistent in their shape and size, yet differences in scale are often the most striking observations when comparisons between species are made [1]. The observation of compensatory growth in which variation in cell number or cell volume results in a consistent organ size, has led to the suggestion that size is controlled at the whole organ level [2,3]. In plants, both morphogen gradients and localized cell-cell interactions have been postulated to be involved in regulating organ shape and size [4,5]. The genes and molecular processes underpinning these regulatory controls have in large part remained unidentified

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Results

Conclusion