Jasmonic acid alleviates cadmium toxicity in Arabidopsis via suppression of cadmium uptake and translocation

Abstract

Jasmonic acid (JA) is thought to be involved in plant responses to cadmium (Cd) stress, but the underlying molecular mechanisms are poorly understood. Here, we show that Cd treatment rapidly induces the expression of genes promoting endogenous JA synthesis, and subsequently increases the JA concentration in Arabidopsis roots. Furthermore, exogenous methyl jasmonate (MeJA) alleviates Cd‐generated chlorosis of new leaves by decreasing the Cd concentration in root cell sap and shoot, and decreasing the expression of the AtIRT1, AtHMA2 and AtHMA4 genes promoting Cd uptake and long‐distance translocation, respectively. In contrast, mutation of a key JA synthesis gene, AtAOS, greatly enhances the expression of AtIRT1, AtHMA2 and AtHMA4, increases Cd concentration in both roots and shoots, and confers increased sensitivity to Cd. Exogenous MeJA recovers the enhanced Cd‐sensitivity of the ataos mutant, but not of atcoi1, a JA receptor mutant. In addition, exogenous MeJA reduces NO levels in Cd‐stressed Arabidopsis root tips. Taken together, our results suggest that Cd‐induced JA acts via the JA signaling pathway and its effects on NO levels to positively restrict Cd accumulation and alleviates Cd toxicity in Arabidopsis via suppression of the expression of genes promoting Cd uptake and long‐distance translocation.

Interplay between Hormones and Several Abiotic Stress Conditions on Arabidopsis thaliana Primary Root Development

“…Consequently, decreasing JA levels magnify the Cd toxicity: the JA synthesis mutant aos, with reduced endogenous JA levels, not only has a shorter PR length than WT plants in the presence of Cd, but accumulates more of this metal. The positive function of JA against Cd stress is mediated through the expression of genes that encode antioxidant enzymes and the suppression of genes that promote the Cd uptake and its translocation from roots to shoots [189] ( Figure 3C and Table S2).…”

Molecular Interaction and Evolution of Jasmonate Signaling With Transport and Detoxification of Heavy Metals and Metalloids in Plants

“…Moreover, increasing pieces of evidence demonstrated the involvement of jasmonates consisting of JA and its derivatives such as jasmonoyl-l-isoleucine (JA-Ile) and methyl-JA in the detoxification and transport of toxic mineral stress (Maksymiec et al, 2005;Chen et al, 2014;Zhao et al, 2016;Wang et al, 2018;Bali et al, 2019;Lei et al, 2020b). Some regulatory mechanisms of jasmonates in response to toxic heavy metals and metalloids have been revealed in model plants (Lei et al, 2020b) and major cereals such as rice (Oryza sativa) (Yu et al, 2012;Azeem, 2018;Mousavi et al, 2020), but the evolutionary origin linking JA signaling and plant tolerance to toxic elements is less studied in other green plants including green algae, bryophytes, lycophytes, ferns, and gymnosperms (Chen et al, 2017;Adem et al, 2020;Deng et al, 2021). These regulatory mechanisms in algae and earlydivergent plants such as ferns may contribute to the removal of heavy metals from water and soil (Ma et al, 2001;Cheng et al, 2019;Manara et al, 2020).…”

SINAT E3 ligases regulate the stability of the ESCRT component FREE1 in response to iron deficiency in plants

“…In addition to the endosomal roles of FREE1 in the cytoplasm, FREE1 undergoes phosphorylation-dependent nucleocytoplasmic shuttling and nuclear-localized FREE1 plays a non-endosomal role in transcriptionally attenuating ABA signaling (Li et al 2019). Furthermore, FREE1 interacts with IRON-REGULATED TRANSPORTER1 (IRT1), controlling the polarization and recycling of IRT1 to the plasma membrane and negatively regulating IRT1-dependent iron absorption in plants (Dubeaux et al 2018;Lei et al 2020). However, it remains unclear how FREE1 activity is decreased in plants, to relieve its inhibitory effect on iron absorption under iron-deficient growth conditions.…”