Role of auxinic herbicide-induced ethylene on hypocotyl elongation and root/hypocotyl radial expansion

Abstract

Effects of auxinic herbicides on growth/development, ethylene biosynthesis and gene expression were studied in Sinapis arvensis as well as wild type, auxin‐resistant and ethylene‐insensitive lines of Arabidopsis thaliana. Expansion of the radius of the root/hypocotyl and inhibition of root and hypocotyl elongation were observed in seedlings of S arvensis and wild‐type A thaliana treated with the auxinic herbicide 2,4‐D. All of these morphological changes, except for inhibition of root elongation, are caused by auxinic herbicide‐induced ethylene biosynthesis, which is caused by transcriptional activation of auxin‐inducible genes encoding 1‐aminocyclopropane‐1‐carboxylic acid synthase (ACS). We are the first to distinguish that two types of signal/mechanism exist; the first results from auxinic herbicide‐induced ethylene while the second mechanism is not mediated by ethylene. We identified and characterized seven members of ACS gene family in wild mustard and studied the auxin‐induced expression of these genes. The significance of these findings in understanding the molecular basis for the morphological changes associated with auxinic herbicide action is discussed. © 2000 Society of Chemical Industry

News from Old Compounds: The Mode of Action of Auxin Herbicides

“…The last gene family encodes the key regulatory enzyme in ethylene biosynthesis that catalyzes the conversion of S-adenosylmethionine into ACC, the direct ethylene precursor [14]. Isoforms of ACC synthase genes are differentially expressed or post-transcriptionally regulated in different species and tissue types during senescence, in response to environmental stress conditions, and by auxins within a few minutes of treatment [27,29]. It is postulated that before a hormone signal is transmitted and a downstream series of molecular, biochemical and physiological events in plant growth and development is elicited, the signal has to be first recognized by a receptor molecule [1O].…”

Efecto del genotipo y fuente de citoquinina en la etapa de iniciación de cultivo in vitro de tejido adulto de Castanea sativa Mill.

“…Se ha demostrado que las auxinas inducen la síntesis de novo de ácido 1-aminocyclopropane-1-carboxílico sintasa (ACC) (Wei et al 2000, Taiz & Zeiger 2012, cuya inducción de la actividad de la ACC sintasa estimula la biosíntesis de etileno, el cual desempeña un papel crucial en el envejecimiento y muerte celular (Wei et al 2000, Sankhla et al 2003. Por lo tanto, podría asociarse con una acumulación de etileno en la zona superior del frasco, producto de la acumulación de auxinas, aunque en este estudio se utilizaron tapas con ventilación.…”

Proteomics: An Emerging Technology for Weed Science Research

“…However, when treated with picloram, the sensitive biotypes produced more ethylene than resistant biotypes Peniuk et al 1993). This was attributed to differences at the primary site of action resulting in reduced expression of ACC synthase (a key enzyme in the ethylene biosynthetic pathway; Grossman 2000Grossman , 2010, concomitant with auxinic herbicide treatment in the resistant biotype Wei et al 2000). Subsequently, a number of experiments were conducted to investigate the role of ABP1 in auxinic herbicide resistance in wild mustard.…”