Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan.
J Exp Bot. 2014 Jan;65(1):261-73. doi: 10.1093/jxb/ert371. Epub 2013 Nov 19.
Exposing plants to hypoxic conditions greatly improves their anoxic stress tolerance by enhancing the activities of glycolysis and fermentation in roots. Ethylene may also be involved in these adaptive responses because its synthesis is increased in roots under hypoxic conditions. Here it is reported that pre-treatment of wheat seedlings with an ethylene precursor, 1-aminocyclopropanecarboxylic acid (ACC), enhanced accumulation of ethylene in the roots of wheat seedlings, and enhanced their tolerance of oxygen-deficient conditions through increasing the expression of genes encoding ethanol fermentation enzymes, alcohol dehydrogenase and pyruvate decarboxylase, in the roots. Lysigenous aerenchyma formation in root was induced by ACC pre-treatment and was further induced by growth under oxygen-deficient conditions. ACC pre-treatment increased the expression of three genes encoding respiratory burst oxidase homologue (a plant homologue of gp91(phox) in NADPH oxidase), which has a role in the generation of reactive oxygen species (ROS), in roots of seedlings. Co-treatment with ACC and an NADPH oxidase inhibitor, diphenyleneiodonium, partly suppressed the ACC-induced responses. These results suggest that ethylene and ROS are involved in adaptation of wheat seedlings to oxygen-deficient conditions through controlling lysigenous aerenchyma formation and the expression of genes encoding ethanol fermentation enzymes.
将植物暴露在缺氧条件下可以通过增强根部糖酵解和发酵的活性来极大地提高其对缺氧胁迫的耐受性。乙烯也可能参与这些适应性反应，因为在缺氧条件下，它在根部的合成增加。在这里，据报道，用乙烯前体 1-氨基环丙烷羧酸（ACC）预处理小麦幼苗会增强小麦幼苗根部乙烯的积累，并通过增加根中编码乙醇发酵酶、乙醇脱氢酶和丙酮酸脱羧酶的基因的表达来增强其对缺氧条件的耐受性。ACC 预处理诱导了根中的溶生性通气组织形成，并且在缺氧条件下生长进一步诱导了溶生性通气组织形成。ACC 预处理增加了三个编码呼吸爆发氧化酶同源物（植物 NADPH 氧化酶中 gp91(phox)的同源物）的基因的表达，该基因在活性氧（ROS）的产生中起作用，幼苗的根。用 ACC 和 NADPH 氧化酶抑制剂二苯乙烯碘处理，部分抑制了 ACC 诱导的反应。这些结果表明，乙烯和 ROS 通过控制溶生性通气组织形成和编码乙醇发酵酶的基因的表达，参与了小麦幼苗对缺氧条件的适应。
