Table_1_Role of Ethylene Biosynthesis Genes in the Regulation of Salt Stress and Drought Stress Tolerance in Petunia.DOCX

Ethylene plays a critical signaling role in the abiotic stress tolerance mechanism. However, the role of ethylene in regulating abiotic stress tolerance in petunia has not been well-investigated, and the underlying molecular mechanism by which ethylene regulates abiotic stress tolerance is still unknown. Therefore, we examined the involvement of ethylene in salt and drought stress tolerance of petunia using the petunia wild type cv. “Merage Rose” and the ethylene biosynthesis genes (PhACO1 and PhACO3)-edited mutants (phaco1 and phaco3). Here, we discovered that editing PhACO1 and PhACO3 reduced ethylene production in the mutants, and mutants were more sensitive to salt and drought stress than the wild type (WT). This was proven by the better outcomes of plant growth and physiological parameters and ion homeostasis in WT over the mutants. Molecular analysis revealed that the expression levels of the genes associated with antioxidant, proline synthesis, ABA synthesis and signaling, and ethylene signaling differed significantly between the WT and mutants, indicating the role of ethylene in the transcriptional regulation of the genes associated with abiotic stress tolerance. This study highlights the involvement of ethylene in abiotic stress adaptation and provides a physiological and molecular understanding of the role of ethylene in abiotic stress response in petunia. Furthermore, the finding alerts researchers to consider the negative effects of ethylene reduction on abiotic stress tolerance when editing the ethylene biosynthesis genes to improve the postharvest quality of horticultural crops.

乙烯（ethylene）在非生物胁迫耐受性（abiotic stress tolerance）机制中发挥关键信号传导作用。然而，乙烯在调控矮牵牛非生物胁迫耐受性中的功能尚未得到充分研究，其调控非生物胁迫耐受性的潜在分子机制仍未明晰。为此，我们以矮牵牛野生型品种"Merage Rose"以及乙烯生物合成基因（PhACO1和PhACO3）编辑突变体（phaco1和phaco3）为材料，探究了乙烯在矮牵牛盐胁迫与干旱胁迫耐受性中的作用。本研究发现，编辑PhACO1与PhACO3可降低突变体的乙烯生成量，且突变体对盐胁迫和干旱胁迫的敏感性较野生型（WT）更高。这一结论通过野生型相较于突变体更优异的植株生长表现、生理参数以及离子稳态得到了验证。分子分析结果显示，野生型与突变体在抗氧化相关基因、脯氨酸合成、脱落酸（abscisic acid，ABA）合成与信号通路以及乙烯信号通路相关基因的表达水平上存在显著差异，表明乙烯在非生物胁迫耐受相关基因的转录调控中发挥作用。本研究阐明了乙烯在非生物胁迫适应过程中的参与性，并为解析乙烯在矮牵牛非生物胁迫应答中的功能提供了生理与分子层面的认知。此外，本研究结果提醒研究者，在编辑乙烯生物合成基因以提升园艺作物采后品质时，需考虑乙烯水平降低对非生物胁迫耐受性带来的负面影响。