Auxin mediates the touch-induced mechanical stimulation of adventitious root formation under windy conditions in Brachypodium distachyon

Bo Eun Nam,Chung-Mo Park,Jae Geun Kim,Young-Joon Park,Ju-Heon Kim,Kyung-Eun Gil

doi:10.1186/s12870-020-02544-8

Abstract

BackgroundIt is widely perceived that mechanical or thigmomorphogenic stimuli, such as rubbing and bending by passing animals, wind, raindrop, and flooding, broadly influence plant growth and developmental patterning. In particular, wind-driven mechanical stimulation is known to induce the incidence of radial expansion and shorter and stockier statue. Wind stimulation also affects the adaptive propagation of the root system in various plant species. However, it is unknown how plants sense and transmit the wind-derived mechanical signals to launch appropriate responses, leading to the wind-adaptive root growth.ResultsHere, we found that Brachypodium distachyon, a model grass widely used for studies on bioenergy crops and cereals, efficiently adapts to wind-mediated lodging stress by forming adventitious roots (ARs) from nonroot tissues. Experimental dissection of wind stimuli revealed that not bending of the mesocotyls but physical contact of the leaf nodes with soil particles triggers the transcriptional induction of a group of potential auxin-responsive genes encoding WUSCHEL RELATED HOMEOBOX and LATERAL ORGAN BOUNDARIES DOMAIN transcription factors, which are likely to be involved in the induction of AR formation.ConclusionsOur findings would contribute to further understanding molecular mechanisms governing the initiation and development of ARs, which will be applicable to crop agriculture in extreme wind climates.

Highlights

It is widely perceived that mechanical or thigmomorphogenic stimuli, such as rubbing and bending by passing animals, wind, raindrop, and flooding, broadly influence plant growth and developmental patterning
Brachypodium adapts to wind-induced lodging stress by forming Adventitious roots (AR) On the basis of the previous observations that wind triggers thigmomorphogenic root responses and auxin plays a major role in inducing AR formation, we hypothesized that auxin-mediated AR formation is associated with wind-induced thigmomorphogenic adaptation in Brachypodium
We found that more ARs were formed from the leaf nodes of the tillers in wind-treated plants (Fig. 2a), raising a possibility that AR formation is responsible for the lodgingtolerant phenotype

Summary

Introduction

It is widely perceived that mechanical or thigmomorphogenic stimuli, such as rubbing and bending by passing animals, wind, raindrop, and flooding, broadly influence plant growth and developmental patterning. Wind stimulation affects the adaptive propagation of the root system in various plant species. It is unknown how plants sense and transmit the wind-derived mechanical signals to launch appropriate responses, leading to the wind-adaptive root growth. Plants are constantly challenged with changes in surrounding environments throughout their life cycles It has long been perceived by agricultural breeders and plant scientists that mechanical stimuli, such as physical. The wind-responsive morphological changes allow plants to avoid stem breakage and uprooting by increasing plant mechanical strength and minimizing the disturbing force from wind [6]. There are many additional morphogenic traits that play roles in inducing lodging tolerance in cereals. The modes of plant lodging responses vary depending on the intensity and timing of lodging stimuli in different plant species [13, 14]

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Results

Conclusion