Diverse Allyl Glucosinolate Catabolites Independently Influence Root Growth and Development.

Ella Katz,Meike Burow,Rammyani Bagchi,Aleshia Hopper,Verena Jeschke,Alycia R M Rasmussen,Daniel J Kliebenstein,Mark Estelle

doi:10.1104/pp.20.00170

Abstract

Glucosinolates (GSLs) are sulfur-containing defense metabolites produced in the Brassicales, including the model plant Arabidopsis (Arabidopsis thaliana). Previous work suggests that specific GSLs may function as signals to provide direct feedback regulation within the plant to calibrate defense and growth. These GSLs include allyl-GSL, a defense metabolite that is one of the most widespread GSLs in Brassicaceae and has also been associated with growth inhibition. Here we show that at least three separate potential catabolic products of allyl-GSL or closely related compounds affect growth and development by altering different mechanisms influencing plant development. Two of the catabolites, raphanusamic acid and 3-butenoic acid, differentially affect processes downstream of the auxin signaling cascade. Another catabolite, acrylic acid, affects meristem development by influencing the progression of the cell cycle. These independent signaling events propagated by the different catabolites enable the plant to execute a specific response that is optimal to any given environment.

Highlights

Pathogens and herbivore attacks are a critical life-long threat to any plant
To develop a deeper mechanistic understanding of how allyl-GSL modulates plant growth, we focused on the effect of allyl-GSL and its associated catabolites on Arabidopsis root growth and root morphology
Raphanusamic acid inhibited dill and lettuce while dramatically inducing root growth in tomato (Fig. 6). These results show that the allyl-GSL catabolites can influence growth across a wide range of species, and that similar to Arabidopsis, it is likely that there are three different mechanisms being targeted

Summary

Introduction

Pathogens and herbivore attacks are a critical life-long threat to any plant. To survive these attackers, plants have developed a variety of defense mechanisms and resistance strategies, including the production of defensive chemicals (Chen 2008). Maximizing the effectiveness while limiting the detriments of these defense chemicals, and the plant immune system in general, requires that they are produced in the proper tissue, cell and developmental stage. This requires a central coordination with the developmental programming of the plant, though the nature of this coordination is yet to be fully understood (Agrawal et al 1999, Campos et al 2016, Guo et al 2018, Kliebenstein 2016, Strauss & Agrawal 1999). Any cost of defense metabolism is likely at most temporary to allow the plant to deal with the immediate threat and increases the long-term fitness potential

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Results

Conclusion