Antagonistic interaction between jasmonic acid and cytokinin in xylem development

Abstract

Developmental flexibility under stress conditions largely relies on the interactions between hormones that mediate stress responses and developmental processes. In this study, we showed that the stress hormone jasmonic acid (JA) induces formation of extra xylem in the roots of wild-type Arabidopsis thaliana (Col-0). JA signaling mutants such as coronatine insensitive1-1 and jasmonate resistant1-1 did not form extra xylem in response to JA, but the JA biosynthesis mutant oxophytodienoate-reductase3 did form extra xylem. These observations suggested that the JA response promotes xylem development. To understand the mechanism, we examined the regulatory interaction between JA and cytokinin, a negative regulator of xylem development. JA treatment reduced cytokinin responses in the vasculature, and exogenous cytokinin nullified the effect of JA on formation of extra xylem. A time-course experiment showed that suppression of cytokinin responses by JA does not occur rapidly, but the JA-mediated xylem phenotype is tightly linked to the suppression of the cytokinin response. Further analysis of arabidopsis histidine phosphotransfer protein6-1 and myc2-3 mutants revealed that the JA-responsive transcription factor MYC2 regulates the expression of AHP6 in response to JA and expression of AHP6 is involved in the JA-mediated xylem phenotype.

MYC2 regulates ARR16, a component of cytokinin signaling pathways, in Arabidopsis seedling development

“…Also, based on ChIP data, it appears that in the absence of cytokinin some other regulatory component, that might work downstream of MYC2, is involved in the regulation of ARR16 . Similar observation has also been made by Jang et al, .…”

Systematic hormone-metabolite network provides insights of high salinity tolerance inPongamia pinnata(L.) pierre

“…The interactive influence of cytokinin may substantiate JAs negative impact to promote plant survival under extreme saline conditions. The synergistic interaction between zeatin and JAs may also enhance the salt induced-vasculature in roots to enhance water uptake, which is also supported by the well maintained RRWC in roots of treated plants (Supplementary Figure 2D) (Ueda Kato, 1982; Nitschke et al, 2016; Jang et al, 2017).…”

Crosstalk with Jasmonic Acid Integrates Multiple Responses in Plant Development

“…Many studies reported that developmental flexibility under stress conditions largely depends on the interplay between stress-related hormones and growth-related hormones, and increasing evidence indicates that JA and GA antagonistically interact to coordinate plant growth and defense [50][51][52]. Extensive studies on the JAZ JA signaling repressor proteins, and the DELLA GA signaling repressor proteins revealed that direct interaction between JAZs and DELLAs mediates the antagonistic interaction between JA and GA ( Figure 1) [27,28].…”

“…The AHPs activated by phosphorylation move into the nucleus and sequentially activate B-type ARABIDOPSIS RESPONSE REGULATOR (ARR) transcription factors responsible for the transcription of cytokinin-responsive genes [69,70]. Genes encoding components of the cytokinin signaling pathways, such as AHKs, AHPs, and ARRs, are affected by JA or environmental stresses such as drought, salt, and cold, suggesting that the cytokinin response is involved in plant stress responses [50,56,71,72].…”

“…Furthermore, JA and cytokinin differently regulate the expression of the genes involved in the chlorophyll development, indicating the existence of an antagonistic interaction between JA and cytokinin. A recent study revealed that xylem differentiation is regulated by JA in Arabidopsis roots, and an antagonistic interaction between JA and cytokinin is fundamentally important for JA-dependent xylem development [50]. Xylem is responsible for water and nutrient transport and it develops from procambial/cambial cells, which are stem cells of the vascular system [76,77].…”