Ahkami Amir H, Lischewski Sandra, Haensch Klaus-T, Porfirova Svetlana, Hofmann Joerg, Rolletschek Hardy, Melzer Michael, Franken Philipp, Hause Bettina, Druege Uwe, Hajirezaei Mohammad R
Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany.
New Phytol. 2009;181(3):613-25. doi: 10.1111/j.1469-8137.2008.02704.x. Epub 2008 Dec 5.
Adventitious root formation (ARF) in the model plant Petunia hybrida cv. Mitchell has been analysed in terms of anatomy, gene expression, enzymatic activities and levels of metabolites. This study focuses on the involvement of wound response and primary metabolism. Microscopic techniques were complemented with targeted transcript, enzyme and metabolite profiling using real time polymerase chain reaction (PCR), Northern blot, enzymatic assays, chromatography and mass spectrometry. Three days after severance from the stock plants, first meristematic cells appeared which further developed into root primordia and finally adventitious roots. Excision of cuttings led to a fast and transient increase in the wound-hormone jasmonic acid, followed by the expression of jasmonate-regulated genes such as cell wall invertase. Analysis of soluble and insoluble carbohydrates showed a continuous accumulation during ARF. A broad metabolite profiling revealed a strong increase in organic acids and resynthesis of essential amino acids. Substantial changes in enzyme activities and metabolite levels indicate that specific enzymes and metabolites might play a crucial role during ARF. Three metabolic phases could be defined: (i) sink establishment phase characterized by apoplastic unloading of sucrose and being probably mediated by jasmonates; (ii) recovery phase; and (iii) maintenance phase, in which a symplastic unloading occurs.
已从解剖学、基因表达、酶活性和代谢物水平等方面对模式植物矮牵牛品种米切尔的不定根形成（ARF）进行了分析。本研究聚焦于伤口响应和初级代谢的参与情况。利用实时聚合酶链反应（PCR）、Northern印迹、酶活性测定、色谱法和质谱法等技术，对微观技术进行了补充，以进行靶向转录本、酶和代谢物分析。从母株上分离三天后，首先出现了分生细胞，这些细胞进一步发育成根原基，最终形成不定根。插条的切除导致伤口激素茉莉酸快速短暂增加，随后茉莉酸调节基因如细胞壁转化酶表达。可溶性和不溶性碳水化合物的分析表明，在不定根形成过程中其持续积累。广泛的代谢物分析显示有机酸大量增加，必需氨基酸重新合成。酶活性和代谢物水平的显著变化表明，特定的酶和代谢物可能在不定根形成过程中起关键作用。可定义三个代谢阶段：（i）库建立阶段，其特征是蔗糖的质外体卸载，可能由茉莉酸介导；（ii）恢复阶段；（iii）维持阶段，其中发生共质体卸载。
