The Role of Auxin-Ethylene Crosstalk in Orchestrating Primary Root Elongation in Sugar Beet

Abstract

It is well-established in Arabidopsis and other species that ethylene inhibits root elongation through the action of auxin. In sugar beet (Beta vulgaris L.) ethylene promotes root elongation in a concentration dependent manner. However, the crosstalk between ethylene and auxin remains unknown during sugar beet seedling development. Our experiments have shown that exogenously applied auxin (indole-3-acetic acid; IAA) also stimulates root elongation. We also show that auxin promotes ethylene biosynthesis leading to longer roots. We have further demonstrated that the auxin treatment stimulates ethylene production by redirecting the pool of available 1-aminocyclopropane-1-carboxylic acid (ACC) toward ethylene instead of malonyl-ACC (MACC) resulting in a prolonged period of high rates of ethylene production and subsequently a longer root. On the other hand we have also shown that endogenous IAA levels were not affected by an ACC treatment during germination. All together our findings suggest that the general model for auxin-ethylene crosstalk during early root development, where ethylene controls auxin biosynthesis and transport, does not occur in sugar beet. On the contrary, we have shown that the opposite, where auxin stimulates ethylene biosynthesis, is true for sugar beet root development.

The Coordination of Ethylene and Other Hormones in Primary Root Development

“…Further investigations should focus on how plants perceive external changes and translate cues into adaptive responses by modulating endogenous hormone crosstalk dynamics. Moreover, there is a complex regulatory network among phytohormones, and different regulatory mechanisms exist in different tissues, at different developmental stages, and in different species (Luo et al, 2014; Ma et al, 2014; Yin et al, 2015; Abts et al, 2017). Thus, researchers should try to understand hormone crosstalk in a multidimensional space, and the development of effective hormone detection methods and computational models will greatly promote research on hormone crosstalk.…”

Auxin-Induced SaARF4 Downregulates SaACO4 to Inhibit Lateral Root Formation in Sedum alfredii Hance

“…For example, ABA upregulated PIN2 under osmotic stress, resulting in decreased auxin content in the root meristem leading to root growth inhibition [ 40 ]. The interactions between auxin and ethylene act in many developmental aspects of plants, such as apical hook development [ 41 ], fruit ripening [ 42 ], and primary root elongation [ 43 ]. It is worth noting that auxin and ethylene regulate LR development based on a certain threshold level [ 11 ].…”

Plant susceptible responses: the underestimated side of plant–pathogen interactions

“…CKs also enhance photoassimilate flow into the gall to maintain the intensive metabolism of hypertrophic cells (Robert‐Seilaniantz et al ., 2007 ; Walters, McRoberts & Fitt, 2008 ; Depuydt et al ., 2009 ). In addition, due to the positive effect of auxin on ET production (Abts et al ., 2017 ; Zemlyanskaya et al ., 2018 ), the synthesis of ET is activated in the gall (Riov & Yang, 1989 ; Vandenbussche et al ., 2003 , 2010 ). In turn, ET induces the synthesis of ABA in the leaves of the infected plants, and ABA is transported into the gall to induce the synthesis of osmolytes and suberin (Efetova et al ., 2007 ).…”