Stable expression of AtGA2ox1 in a low-input turfgrass (Paspalum notatum Flugge) reduces bioactive gibberellin levels and improves turf quality under field conditions
Stable expression of AtGA2ox1 in a low-input turfgrass (Paspalum notatum Flugge) reduces bioactive gibberellin levels and improves turf quality under field conditions
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DOI：
10.1111/j.1467-7652.2007.00284.x
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发表时间：
2007-11-01
影响因子：
13.8
通讯作者：
Lange, Theo
中科院分区：
文献类型：
--
作者：
Agharkar, Mrinalini;Lomba, Paula;Lange, Theo
百喜草（Paspalum notatum Flugge）是分子改良草坪质量的主要候选植物。它的持久性和低投入的特点，使它的优势实用草坪草沿着高速公路在美国东南部。然而，由于草坪密度降低和多产难看的花序导致的相对较差的草坪质量目前限制了百喜草作为住宅草坪的广泛使用。通过应用生长调节剂或转基因策略改变内源赤霉素（GA）水平已经改变了几种作物的植株结构。GA分解代谢AtGA 2 ox 1在组成型玉米泛素启动子和Nos 3 'UTR的控制下被亚克隆。一个最小的AtGA 2 ox 1表达盒缺乏载体骨架序列稳定地引入到无融合生殖百喜草的基因枪转移证实了Southern印迹分析。通过逆转录-聚合酶链反应和北方印迹分析表明，AtGA 2 ox 1在百喜草中的表达导致了与野生型相比内源生物活性GA（1）水平的显著降低。有趣的是，转基因植物表现出增加的营养分蘖与AtGA 2 ox 1的表达水平和增强草坪密度在田间条件下。这表明，气体有助于信号在这个多年生草腋芽的生长。转基因植株在受控环境和田间条件下也表现出茎长减少和开花延迟。因此，每周割草后的草坪质量在转基因百喜草中得到改善。转基因表达和表型传递到种子后代。阿根廷百喜草通过无融合生殖无性产生种子，这降低了花粉无意中传播转基因的风险，并产生统一的后代。
Bahiagrass (Paspalum notatum Flugge) is a prime candidate for molecular improvement of turf quality. Its persistence and low input characteristics made it the dominant utility turfgrass along highways in the south-eastern USA. However, the comparatively poor turf quality due to reduced turf density and prolific production of unsightly inflorescences currently limits the widespread use of bahiagrass as residential turf. Alteration of endogenous gibberellin (GA) levels by application of growth regulators or transgenic strategies has modified plant architecture in several crops. GA catabolizing AtGA2ox1 was subcloned under the control of the constitutive maize ubiquitin promoter and Nos 3'UTR. A minimal AtGA2ox1 expression cassette lacking vector backbone sequences was stably introduced into apomictic bahiagrass by biolistic gene transfer as confirmed by Southern blot analysis. Expression of AtGA2ox1 in bahiagrass as indicated by reverse transcription-polymerase chain reaction and Northern blot analysis resulted in a significant reduction of endogenous bioactive GA(1) levels compared to wild type. Interestingly, transgenic plants displayed an increased number of vegetative tillers which correlated with the level of AtGA2ox1 expression and enhanced turf density under field conditions. This indicates that GAs contribute to signalling the outgrowth of axillary buds in this perennial grass. Transgenic plants also showed decreased stem length and delayed flowering under controlled environment and field conditions. Consequently, turf quality following weekly mowing was improved in transgenic bahiagrass. Transgene expression and phenotype were transmitted to seed progeny. Argentine bahiagrass produces seeds asexually by apomixis, which reduces the risk of unintended transgene dispersal by pollen and results in uniform progeny.