LOVE ON WINGS, a Dof family protein regulates floral vasculature in Vigna radiata

Wuxiu Guo,Qincheng Peng,Da Luo,Xue Zhang,Shihao Su,Keyuan Jiao

doi:10.1186/s12870-019-2099-x

Wuxiu Guo, Qincheng Peng + Show 4 more

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https://doi.org/10.1186/s12870-019-2099-x

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Abstract

BackgroundThe interaction among plants and their pollinators has been a major factor which enriched floral traits known as pollination syndromes and promoted the diversification of flowering plants. One of the bee-pollination syndromes in Faboideae with keel blossoms is the formation of a landing platform by wing and keel petals. However, the molecular mechanisms of elaborating a keel blossom remain unclear.ResultsBy performing large scale mutagenesis, we isolated and characterized a mutant in Vigna radiata, love on wings (low), which shows developmental defects in petal asymmetry and vasculature, leading to a failure in landing platform formation. We cloned the locus through map-based cloning together with RNA-sequencing (RNA-seq) analysis. We found that LOW encoded a nucleus-localized Dof-like protein and was expressed in the flower provascular and vascular tissues. A single copy of LOW was detected in legumes, in contrast with other taxa where there seems to be at least 2 copies. Thirty one Dof proteins have been identified from the V. radiata’s genome, which can be further divided into four Major Cluster of Orthologous Groups (MCOGs). We also showed that ectopic expression of LOW in Arabidopsis driven by its native promoter caused changes in petal vasculature pattern.ConclusionsTo summarize, our study isolated a legume Dof-like factor LOW from V. radiata, which affects vasculature development in this species and this change can, in turn, impact petal development and overall morphology of keel blossom.

Highlights

The interaction among plants and their pollinators has been a major factor which enriched floral traits known as pollination syndromes and promoted the diversification of flowering plants
A single copy of LOVE ON WINGS (LOW) was detected in legumes in contrast with other taxa, and we found that ectopic expression of LOW in Arabidopsis disrupted the petal vasculature
The right lateral petal encloses the right ventral petal, whilst the left lateral petal is inflexed over the spur developed on left ventral petal, and together they form the landing platform on the left side of the flower (Additional file 1: Figure S1A)

Summary

Introduction

The interaction among plants and their pollinators has been a major factor which enriched floral traits known as pollination syndromes and promoted the diversification of flowering plants. The majority of flowering plants have different strategies in order to attract pollinators, such as alterations in floral color, size, scent, nectar as well as shape These changes are, in turn, under selection by different pollinators, resulting in a collection of floral traits known as pollination syndromes [1]. No apparent phenotype was observed in the single mutant of dof5.8, but it enhanced the cotyledon vascular defects of a weak allele of auxin response factor 5–2, indicating that Dof5.8 functions in an auxin-dependent regulation [25] Another close paralog Dof3.4, or DOF TF OBF BINDING PROTEIN 1, which shows similar expression to Dof5.8, may act redundantly in the control of leaf vascular development [26]. We further cloned the LOW locus, which encodes a plant specific Dof-like transcription factor localized to the nucleus and expressed in the flower vascular tissues

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