Department of Plant Biology, Institute of Biology, Faculty of Science and Informatics, University of Szeged, Közép Fasor 52, H-6726, Szeged, Hungary.
Department of Plant Biology, Institute of Biology, Faculty of Science and Informatics, University of Szeged, Közép Fasor 52, H-6726, Szeged, Hungary; Doctoral School of Biology, University of Szeged, Szeged, Hungary.
J Plant Physiol. 2023 Aug;287:154041. doi: 10.1016/j.jplph.2023.154041. Epub 2023 Jun 14.
Plant defence responses induced by the bacterial elicitor flg22 are highly dependent on phytohormones, including gaseous ethylene (ET). While the regulatory role of ET in local defence responses to flg22 exposure has been demonstrated, its contribution to the induction of systemic responses is not clearly understood. For this consideration, we examined the effects of different ET modulators on the flg22-induced local and systemic defence progression. In our experiments, ET biosynthesis inhibitor aminoethoxyvinyl glycine (AVG) or ET receptor blocker silver thiosulphate (STS) were applied 1 h before flg22 treatments and 1 h later the rapid local and systemic responses were detected in the leaves of intact tomato plants (Solanum lycopersicum L.). Based on our results, AVG not only diminished the flg22-induced ET accumulation locally, but also in the younger leaves confirming the role of ET in the whole-plant expanding defence progression. This increase in ET emission was accompanied by increased local expression of SlACO1, which was reduced by AVG and STS. Local ET biosynthesis upon flg22 treatment was shown to positively regulate local and systemic superoxide (O) and hydrogen peroxide (HO) production, which in turn could contribute to ET accumulation in younger leaves. Confirming the role of ET in flg22-induced rapid defence responses, application of AVG reduced local and systemic ET, O and HO production, whereas STS reduced it primarily in the younger leaves. Interestingly, in addition to flg22, AVG and STS induced stomatal closure alone at whole-plant level, however in the case of combined treatments together with flg22 both ET modulators reduced the rate of stomatal closure in the older- and younger leaves as well. These results demonstrate that both local and systemic ET production in sufficient amounts and active ET signalling are essential for the development of flg22-induced rapid local and systemic defence responses.
植物防御反应由细菌激发子 flg22 诱导，高度依赖于植物激素，包括气态乙烯 (ET)。虽然已经证明 ET 在局部防御反应中对 flg22 暴露的调节作用，但它对全身反应的诱导作用尚不清楚。出于这个考虑，我们研究了不同 ET 调节剂对 flg22 诱导的局部和全身防御进展的影响。在我们的实验中，ET 生物合成抑制剂氨基乙氧基乙烯基甘氨酸 (AVG) 或 ET 受体阻滞剂硫代硫酸银 (STS) 在 flg22 处理前 1 小时和 1 小时后应用于完整番茄植株 (Solanum lycopersicum L.) 的叶片，检测快速的局部和全身反应。根据我们的结果，AVG 不仅减少了 flg22 诱导的 ET 在局部的积累，而且在较年轻的叶片中也减少了 ET 的积累，证实了 ET 在整个植株扩展防御进展中的作用。这种 ET 排放的增加伴随着 SlACO1 的局部表达增加，AVG 和 STS 可减少 SlACO1 的表达。flg22 处理后局部 ET 生物合成被证明正向调节局部和全身超氧化物 (O) 和过氧化氢 (HO) 的产生，这反过来又有助于年轻叶片中 ET 的积累。证实 ET 在 flg22 诱导的快速防御反应中的作用，AVG 的应用减少了局部和全身 ET、O 和 HO 的产生，而 STS 主要减少了年轻叶片中的 ET、O 和 HO 的产生。有趣的是，除了 flg22，AVG 和 STS 单独在整个植株水平上诱导气孔关闭，然而，在与 flg22 联合处理的情况下，两种 ET 调节剂都降低了较老和较年轻叶片的气孔关闭速度。这些结果表明，局部和全身 ET 的产生需要达到足够的数量和有效的 ET 信号，这对于 flg22 诱导的快速局部和全身防御反应的发展是必不可少的。
