Arabidopsis EIN2 modulates stress response through abscisic acid response pathway

Abstract

The nuclear protein ETHYLENE INSENSITIVE2 (EIN2) is a central component of the ethylene signal transduction pathway in plants, and plays an important role in mediating cross-links between several hormone response pathways, including abscisic acid (ABA). ABA mediates stress responses in plants, but there is no report on the role of EIN2 on plant response to salt and osmotic stresses. Here, we show that EIN2 gene regulates plant response to osmotic and salt stress through an ABA-dependent pathway in Arabidopsis. The expression of the EIN2 gene is down-regulated by salt and osmotic stress. An Arabidopsis EIN2 null mutant was supersensitive to both salt and osmotic stress conditions. Disruption of EIN2 specifically altered the expression pattern of stress marker gene RD29B in response to the stresses, but not the stress- or ABA-responsive genes RD29A and RD22, suggesting EIN2 modulates plant stress responses through the RD29B branch of the ABA response. Furthermore, disruption of EIN2 caused substantial increase in ABA. Lastly, our data showed that mutations of other key genes in ethylene pathway also had altered sensitivity to abiotic stresses, indicating that the intact ethylene may involve in the stress response. Taken together, the results identified EIN2 as a cross-link node in ethylene, ABA and stress signaling pathways, and EIN2 is necessary to induce developmental arrest during seed germination, and seedling establishment, as well as subsequent vegetative growth, thereby allowing the survival and growth of plants under the adverse environmental conditions.

A Soybean Dual-Specificity Kinase, GmSARK, and Its Arabidopsis Homolog, AtSARK, Regulate Leaf Senescence through Synergistic Actions of Auxin and Ethylene

“…The aux1-7 mutation in this gene confers both auxin and ethylene resistance (Pickett et al, 1990). In addition to its role as a central component of the ethylene signal transduction pathway (Alonso et al, 1999;An et al, 2010), EIN2 also functions as a cross-link node in ethylene and other phytohormone signaling pathways (Ghassemian et al, 2000;Wang et al, 2007). We found that the ein2-1 seedlings also exhibited insensitivity to exogenous IAA (data not shown).…”

MBF1s regulate ABA-dependent germination of Arabidopsis seeds

“…[13][14][15][16][17] We analyzed the effect of AtMBF1 mutations on seed dormancy of abc-seeds and compared with ein3-1 mutant and abc-complemented with AtMBF1c gene overexpression (abc-+c).…”

“…13,14 Ein 2 null mutant is also supersensitive to both salt and osmotic stress conditions. 15 All these data suggest that a functional ethylene signal transduction pathway is necessary to fully develop several ABA responses. As we commented before there are evidences that MBF1 genes positively regulate ethylene signaling pathway.…”

Sugar-Hormone Cross-Talk in Anthocyanin Biosynthesis

“…Furthermore, the interaction between different hormones also needs to be considered, and several genetic mutants have been isolated that may help clarify the effect of hormones on anthocyanin biosynthesis. For example, high ABA levels in the ein2 mutant might be responsible for the high anthocyanin accumulation in these plants, demonstrating the dual regulation of ABA and ethylene signaling (Wang et al, 2007). New screening strategies coupled with proteomic and genomic techniques might further clarify the regulation of anthocyanin biosynthesis.…”