氣候變遷所造成的影響是現在人類所需面臨的重要議題。高溫在農業上會造成許多植物如: 豆、青花菜、棉和番茄等花器發育不全。以青花菜(Brassica oleracea L. var. italica)為例，其維生素、礦物質和抗癌物質磺胺胡蘿蔔素(sofulraphane)、硫配醣體(glucosinolate)等含量豐富，使青花菜成為營養價值相當高的蔬菜作物。然而溫帶作物青花菜喜好的生長環境平均溫度低於25°C，且花球形成需經過低溫春化處理，所以台灣在夏天時常無法自產青花菜。因此本研究利用耐熱與不耐熱品系之青花菜，探討兩者在高溫下花球形成之模式與開花基因相關轉錄因子表現活性。將青花菜分別利用高溫(27°C)和低溫(15°C)處理，以比較花球發育情形和開花相關基因的表現量發現: 耐熱青花菜不管在高溫或低溫處理下皆形成花球，不耐熱青花菜只在有低溫處理才能形成花球；而調控開花的相關基因BoFLC1與BoFT的表現量也與花球形成時間成高度相關。同時分析比較兩不同品系青花菜的FLC1基因啟動子(promoter)序列，結果顯示兩品系的啟動子在不同位置中分別存在14- 22個核苷酸缺失(deletion)現象，這很可能是造成兩品系於高溫逆境時基因表現量出現差異的原因。最後更進一步以寡核酸微陣列(Oligonucleotide microarray)分析兩品系青花菜在高溫逆境下的基因表現量，結果發現不耐熱品系的青花菜在22°C時即誘發熱休克蛋白(Heat shock proteins)基因的表現，而耐熱品系則需到更高溫時(27°C)才被誘導表現，這表示不耐熱品系對高溫的敏銳程度高於耐熱品系。本研究對青花菜在高溫逆境下開花相關基因進行探討，揭開植物在面對高溫逆境時的開花機制，並利用變異的啟動子序列篩選出具有高溫開花耐受性的植株，期許在未來能解決全球暖化衝擊下對農業作物所帶來的危機。

Broccoli (Brassica oleracea L. var. italica), which contains high concentration of vitamins, minerals and anti-cancer substance (such as sofulraphae and glucosinolate), is a high nutritional value vegetable crop. However, like all other temperate crops, flowering only occurs when plants get vernalized. Most broccoli strains can not produce the curd in summer, however some strains can. In this study, two pure lines of broccoli were used to monitor the different curd- forming capacity. The heat- tolerant broccoli plant lines (Cheng-Long Early; CNE) exhibit better curd-forming capacity at relatively high temperature (27°C). In contrast, the heat- sensitive broccoli plants (regular broccoli lines) are unable to produce curd at 27°C. The expression of BoFLC1, a well- known negative regulator of flowering, was investigated and served as a molecular marker to distinguish between these two plant lines. In addition, we isolated FLC homologs from broccoli and investigated their transcript levels in heat- tolerant and heat- sensitive broccoli lines. To further investigate the differential expression of BoFLC1 in early and late lines at higher temperature, the promoter sequences corresponding to the two plant lines were cloned and sequenced. Subsequently, microarray experiment was performed to track the transcriptomic changes, including transcription factors, kinases and signalling components. Furthermore, the differential expression of Heat shock proteins (Hsps) in response to relatively high temperature were compared between these two broccoli lines. The differential HSP expression may reflect their sensitivity to high temperature. The global genomic expression shed light on the molecular mechanisms underlying the curd formation in broccoli. These differential gene expression and their sequences variants may be used by breeders as molecular markers and provide an opportunity to uncover different regulatory mechanisms on flowering in higher temperature in Brassica species.

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