S-adenosyl-L-methionine usage during climacteric ripening of tomato in relation to ethylene and polyamine biosynthesis and transmethylation capacity.
S-adenosyl-L-methionine usage during climacteric ripening of tomato in relation to ethylene and polyamine biosynthesis and transmethylation capacity.
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DOI：
10.1111/j.1399-3054.2012.01703.x
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发表时间：
2013-06
影响因子：
6.4
通讯作者：
B. Van de Poel;I. Bulens;Yasmin Oppermann;M. Hertog;B. Nicolai;M. Sauter;A. Geeraerd
中科院分区：
文献类型：
--
作者：
B. Van de Poel;I. Bulens;Yasmin Oppermann;M. Hertog;B. Nicolai;M. Sauter;A. Geeraerd
S-腺苷-L-甲硫氨酸 (SAM) 是细胞中主要的甲基供体，也用于多胺和植物激素乙烯的生物合成。在番茄（Solanum lycopersicum 'Bonaparte'）的更年期成熟过程中，乙烯产量显着增加，这使其成为研究 SAM 参与的理想对象。我们在成熟的果实中研究了 1-MCP 处理如何通过三个主要 SAM 相关途径影响 SAM 的使用。 1-MCP 处理抑制自催化乙烯产生，但不影响 SAM 水平。我们还观察到成熟过程中 1-(丙二酰氨基)环丙烷-1-羧酸的形成依赖于乙烯。还发现乙烯上调了 SAM 脱羧酶的表达。尽管如此，1-MCP 处理的水果中多胺含量较高。由此得出乙烯和多胺途径可以同时运行的结论。我们还观察到 1-MCP 处理的水果具有更高的甲基化能力。在果实成熟过程中，发生大量甲基化反应，该反应逐渐被甲基化产物 S-腺苷-L-同型半胱氨酸 (SAH) 抑制。 SAH 积累是由腺苷激酶表达下降引起的，在 1-MCP 处理的水果中未观察到这种情况。我们可以得出结论，番茄果实具有在成熟过程中同时消耗SAM的能力，以确保乙烯和多胺的高产率和转甲基反应。成熟过程中 SAM 的使用需要复杂的细胞调节机制来控制 SAM 水平。
S-adenosyl-L-methionine (SAM) is the major methyl donor in cells and it is also used for the biosynthesis of polyamines and the plant hormone ethylene. During climacteric ripening of tomato (Solanum lycopersicum 'Bonaparte'), ethylene production rises considerably which makes it an ideal object to study SAM involvement. We examined in ripening fruit how a 1-MCP treatment affects SAM usage by the three major SAM-associated pathways. The 1-MCP treatment inhibited autocatalytic ethylene production but did not affect SAM levels. We also observed that 1-(malonylamino)cyclopropane-1-carboxylic acid formation during ripening is ethylene dependent. SAM decarboxylase expression was also found to be upregulated by ethylene. Nonetheless polyamine content was higher in 1-MCP-treated fruit. This leads to the conclusion that the ethylene and polyamine pathway can operate simultaneously. We also observed a higher methylation capacity in 1-MCP-treated fruit. During fruit ripening substantial methylation reactions occur which are gradually inhibited by the methylation product S-adenosyl-L-homocysteine (SAH). SAH accumulation is caused by a drop in adenosine kinase expression, which is not observed in 1-MCP-treated fruit. We can conclude that tomato fruit possesses the capability to simultaneously consume SAM during ripening to ensure a high rate of ethylene and polyamine production and transmethylation reactions. SAM usage during ripening requires a complex cellular regulation mechanism in order to control SAM levels.