Constitutive expression of EIL-like transcription factor partially restores ripening in the ethylene-insensitive Nr tomato mutant
Constitutive expression of EIL-like transcription factor partially restores ripening in the ethylene-insensitive Nr tomato mutant
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DOI：
10.1093/jxb/erh168
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发表时间：
2004-07-01
影响因子：
6.9
通讯作者：
Grierson, D
中科院分区：
文献类型：
--
作者：
Chen, GP;Alexander, L;Grierson, D
跃变型果实的成熟受植物激素乙烯的调节。乙烯不敏感3（EIN 3）是拟南芥乙烯信号转导途径中乙烯受体下游的一个转录因子。拟南芥EIN 3基因的三个同源物已在番茄中鉴定，番茄EIN 3样或LeEIL，LeEIL 1，LeEIL 2和LeEIL 3。这些转录因子被认为是多种乙烯反应的功能冗余正调控因子。为了检测这些因子在番茄成熟过程中乙烯信号转导途径中的作用，将融合有绿色荧光蛋白（GFP）的EIL 1在番茄乙烯不敏感的非成熟Nr突变体中过量表达。LeEIL1水平的增加弥补了Nr突变体中LeEIL1水平的正常降低，并且表现出高水平组成型表达LeEIL1GFP的转基因Nr植物表型类似于野生型植物，果实成熟，叶片表现出上向性，不像Nr植物。EIL 1GFP融合蛋白定位于成熟番茄果实的细胞核中。这些植物的mRNA表达谱显示，某些乙烯依赖性成熟基因的表达上调，包括多聚半乳糖醛酸酶和TOMLOX B。然而，并不是所有的成熟基因和乙烯反应，如幼苗三重反应，恢复。这些结果表明，在Nr乙烯不敏感背景下表达候选基因是一种有价值的通用方法，用于测试推定的下游组分在乙烯信号传导途径中的作用。
Climacteric fruit ripening is regulated by the phytohormone ethylene. ETHYLENE-INSENSITIVE3 (EIN3) is a transcription factor that functions downstream from the ethylene receptors in the Arabidopsis ethylene signal transduction pathway. Three homologues of the Arabidopsis EIN3 gene have been identified in tomato, Lycopersicon esculentum, EIN3-like or LeEIL, LeEIL1, LeEIL2, and LeEIL3. These transcription factors have been proposed to be functionally redundant positive regulators of multiple ethylene responses. In order to test the role of such factors in the ethylene signal transduction pathway during ripening, EIL1 fused to green fluorescent protein (GFP) has been over-expressed in the ethylene-insensitive non-ripening Nr mutant of tomato. Increased levels of LeEIL1 compensated for the normally reduced levels of LeEIL1 in the Nr mutant, and transgenic Nr plants that exhibited high-level constitutive expression of LeEIL1GFP phenotypically resembled wild-type plants, the fruit ripened and the leaves exhibited epinasty, unlike Nr plants. The EIL1GFP fusion protein was located in the cell nuclei of ripe tomato fruit. The mRNA profile of these plants showed that the expression of certain ethylene-dependent ripening genes was up-regulated, including polygalacturonase and TOMLOX B. However, not all ripening genes and ethylene responses, such as seedling triple response, were restored. These results demonstrate that expressing candidate genes in the Nr ethylene-insensitive background is a valuable general approach for testing the role of putative downstream components in the ethylene-signalling pathway.