Overexpression of DWARF4 in the brassinosteroid biosynthetic pathway results in increased vegetative growth and seed yield in Arabidopsis
Overexpression of DWARF4 in the brassinosteroid biosynthetic pathway results in increased vegetative growth and seed yield in Arabidopsis
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DOI：
10.1046/j.1365-313x.2001.01055.x
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发表时间：
2001-06-01
期刊：
影响因子：
7.2
通讯作者：
Feldmann, KA
中科院分区：
文献类型：
--
作者：
Choe, S;Fujioka, S;Feldmann, KA
不能合成或感知油菜素类固醇（BR）的植物是侏儒。拟南芥dwf 4在类固醇22 α羟化酶（CYP 90 B1）步骤中有缺陷，该步骤是BR生物合成途径中假定的限速步骤。为了更好地理解DWF 4在BR生物合成中的作用，使用花椰菜花叶病毒35 S启动子产生异位过表达DWF 4（AOD 4）的转基因拟南芥植物，并表征其表型。与野生型相比，光生长和暗生长的AOD 4幼苗的下胚轴长度显著增加。在成熟时，相对于对照，AOD 4系的花序高度增加>35%，烟草DWF 4过表达系（TOD 4）的花序高度增加>14%。AOD 4植物的分枝和角果总数增加了两倍多，导致产生的种子数量增加了59%。对dwf 4、Ws-2和AOD 4中内源性BR水平的分析揭示，dwf 4积累了22 α-羟基化步骤的前体，而DWF 4的过表达导致下游化合物相对于Ws-2的水平增加，表明通过该步骤的代谢流被促进。DWF 4转录水平和BR表型效应分别在dwf 4、野生型和AOD 4植物中逐渐增加。这表明通过在植物中工程化DWF 4转录来控制植物生长将是可能的。
Plants unable to synthesize or perceive brassinosteroids (BRs) are dwarfs. Arabidopsis dwf4 was shown to be defective in a steroid 22 alpha hydroxylase (CYP90B1) step that is the putative rate-limiting step in the BR biosynthetic pathway. To better understand the role of DWF4 in BR biosynthesis, transgenic Arabidopsis plants ectopically overexpressing DWF4 (AOD4) were generated, using the cauliflower mosaic virus 35S promoter, and their phenotypes were characterized. The hypocotyl length of both light- and dark-grown AOD4 seedlings was increased dramatically as compared to wild type. At maturity, inflorescence height increased >35% in AOD4 lines and >14% in tobacco DWF4 overexpressing lines (TOD4), relative to controls. The total number of branches and siliques increased more than twofold in AOD4 plants, leading to a 59% increase in the number of seeds produced. Analysis of endogenous BR levels in dwf4, Ws-2 and AOD4 revealed that dwf4 accumulated the precursors of the 22 alpha -hydroxylation steps, whereas overexpression of DWF4 resulted in increased levels of downstream compounds relative to Ws-2, indicative of facilitated metabolic flow through the step. Both the levels of DWF4 transcripts and BR phenotypic effects were progressively increased in dwf4, wild-type and AOD4 plants, respectively. This suggests that it will be possible to control plant growth by engineering DWF4 transcription in plants.