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Upregulation of Photosynthesis Genes, and Downregulation of Stress Defense Genes, is the Response of Arabidopsis Thaliana Shoots to Intraspecific Competition

光合作用基因的表現量增加,及防禦基因的表現量下降,是阿拉伯芥地上部面臨種內競爭的反應

摘要


植物彼此競爭光,水和土壤的養分。當植物面臨不同非生物因素(abiotic) 或生物因素(biotic) 的競爭壓力時,到底哪一基因系列表現量(gene expression) 會增加或減少,這個研究主題從未被瞭解過。然而,當使用模式植物系統(model organisms;如阿拉伯芥Arabidopsis thaliana) 作實驗時,植物間彼此競爭中,某一系列基因表現量增加或減少,會大大影響植物-植物間的相互作用,以及影響研究人員實驗設計的準確度。通常在阿拉伯芥研究中,研究表現型和生理特性時,是以單一植株或低密度種植;用於收集大量組織和種子,是以中等密度種植; 用於篩選變異植株時,是以高密度種植。可是,用生物辨識系統(biometric measures) 研究阿拉伯芥的生長和產量時,花序的高度,叢生葉直徑(rosette leafdiameter),生物量(biomass),和種子產量,都會隨著阿拉伯芥生長於中,高密度時而遞減;並且在高密度時,瀕臨所用的盆子的承擔受量(carrying capacity)。收集地上部的莖葉,萃取它們的核糖核酸(RNA)以分析基因轉錄 (transcriptomic analysis)。我們發現到:隨著阿拉伯芥 生長密度的調高,光合作用相關的基因表現量明顯增加;然而那些因環境壓力,植物二級代謝物(plant secondary metabolites),和植物防禦反應(plant defense) 相關的基因表現量卻被大大抑制。無論生長在低和高密度,它們基因表現量和相關性有明顯的重疊。阿拉伯芥面臨種內競爭(intraspecific competition) 的生存策略,似乎和面臨資源被剝奪(resource deprivation) 的影響-無論非生物因素或生物因素資源-完全不同 。所以,我們的結論是:在典型的生長箱(growth chamber) 中,當植物處於種內競爭時,光合作用的基因表現量明顯增加(upregulation),而和環境壓力和植物防禦反應相關的基因表現將被抑制停止(downregulation)。

並列摘要


Plants compete with each other for light, water, and soil nutrients. The extent to which gene expression is affected by the suite of biotic and abiotic stresses involved in competitive response is unknown but has relevance for our basic understanding of plant-plant interactions as well as experimental protocols when using model organisms. Arabidopsis was planted in isolated pots, or at low densities typically used in phenotypic and physiological characterization, at medium densities typical of bulk tissue and seed generation, and at high density typical of mutant screens. Biometric measures for growth and yield showed progressive reduction in inflorescence height, rosette diameter, biomass gain, and seed yield at medium and high densities, and had approached the carrying capacity of our pots at high density. Shoot and leaf RNA was harvested for transcriptomic analysis. Genes involved in photosynthesis were upregulated in response to density stress, while those involved in abiotic stress response, secondary metabolism, and pathogen defense were strongly suppressed. There was significant overlap and correlation between gene expression in low and high densities. Arabidopsis survival strategy for intraspecific competition appears to be completely different to that for deprivation of resources, biotic and abiotic stresses. Plants in these typical growth chamber conditions responded to competition by strongly up-regulating photosynthesis genes while shutting down stress response and pathogen defense pathways.

被引用紀錄


Ye, J. H. (2005). IGFBP-3基因表達在卵巢類子宮內膜腺癌中之功能分析 [master's thesis, National Taiwan University]. Airiti Library. https://doi.org/10.6342%2fNTU.2005.00972

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