Jasmonate signaling involves the abscisic acid receptor PYL4 to regulate metabolic reprogramming in Arabidopsis and tobacco

Abstract

The phytohormones jasmonates (JAs) constitute an important class of elicitors for many plant secondary metabolic pathways. However, JAs do not act independently but operate in complex networks with crosstalk to several other phytohormonal signaling pathways. Here, crosstalk was detected between the JA and abscisic acid (ABA) signaling pathways in the regulation of tobacco (Nicotiana tabacum) alkaloid biosynthesis. A tobacco gene from the PYR/PYL/RCAR family, NtPYL4, the expression of which is regulated by JAs, was found to encode a functional ABA receptor. NtPYL4 inhibited the type-2C protein phosphatases known to be key negative regulators of ABA signaling in an ABA-dependent manner. Overexpression of NtPYL4 in tobacco hairy roots caused a reprogramming of the cellular metabolism that resulted in a decreased alkaloid accumulation and conferred ABA sensitivity to the production of alkaloids. In contrast, the alkaloid biosynthetic pathway was not responsive to ABA in control tobacco roots. Functional analysis of the Arabidopsis (Arabidopsis thaliana) homologs of NtPYL4, PYL4 and PYL5, indicated that also in Arabidopsis altered PYL expression affected the JA response, both in terms of biomass and anthocyanin production. These findings define a connection between a component of the core ABA signaling pathway and the JA responses and contribute to the understanding of the role of JAs in balancing tradeoffs between growth and defense.nicotine | phenylpropanoid | primary metabolism | secondary metabolism | stress response

A bHLH-Type Transcription Factor, ABA-INDUCIBLE BHLH-TYPE TRANSCRIPTION FACTOR/JA-ASSOCIATED MYC2-LIKE1, Acts as a Repressor to Negatively Regulate Jasmonate Signaling inArabidopsis

“…Not only synergistic, but also antagonistic, interactions between JA and ABA signaling were observed in response to various biotic and abiotic stresses in Arabidopsis (Anderson et al, 2004;Kazan and Manners, 2008). The Arabidopsis ABA receptor mutants pyl4 and pyl5 showed JAhypersensitive shoot growth as well as reduced anthocyanin accumulation in response to JA (Lackman et al, 2011). JAM1 may act oppositely in JA and ABA signaling and fine-tune the responses to these two plant hormones.…”

The unique mode of action of a divergent member of the ABA-receptor protein family in ABA and stress signaling

“…Although the PYL family proteins have been studied intensively in recent years [6,[28][29][30][31], little information is available for PYL13, which differs from other PYLs in the highly conserved regions of their ABA-binding pocket. To study the function of PYL13, we examined the interaction of PYL13 with clade A PP2Cs and the effects of PYL13 on the PP2Cs both in vitro and in vivo.…”

The RING E3 Ligase KEEP ON GOING Modulates JASMONATE ZIM-DOMAIN12 Stability

“…Furthermore, several points of cross talk between JA and ABA signaling have been reported, possibly underlying the complex interplay between these pathways in disease resistance (Anderson et al, 2004). For instance, the genes encoding the ABA receptors PYRABACTIN RESISTANCE-LIKE4 (PYL4) and PYL5 are up-regulated by JA, and their mutants show altered JA responses (Lackman et al, 2011). Conversely, MYC2 also plays an important role in this cross talk, as it had been identified as a positive regulator of ABA signaling (Abe et al, 2003;Lorenzo et al, 2004).…”