圖1. 美國佛羅里達大學的研究人員們，已經利用CRISPR/Cas9改造甘蔗的葉角(葉片與葉鞘之間的彎曲程度)，顯著提高其陽光捕獲及生物量產量。在編輯甘蔗複雜之多倍體基因體方面的該項突破，標誌著作物改良及生物燃料生產的重大進展。

Researchers at the University of Florida have utilized CRISPR/Cas9 to modify the leaf angle of sugarcane, significantly enhancing its sunlight capture and biomass yield. This breakthrough in editing the complex, polyploid genome of sugarcane marks a major advancement in crop improvement and biofuel production.

Sugarcane ranks as the top crop globally in terms of biomass yield, contributing to 80 percent of sugar and 40 percent of biofuel production around the world. Its substantial size and optimal utilization of water and light position it as an ideal source for generating innovative renewable bioproducts and biofuels.

根據生物量產量，甘蔗列居全球最上層的作物，為全球提供80%的糖產量及40%的生物燃料產量。其可觀的規模及有關水與光線的最佳利用確立其成為，生產創新、可再生之生物產物及生物燃料理想來源的地位。

However, as a hybrid of Saccharum officinarum and Saccharum spontaneum, sugarcane has the most complex genome of all crops. This complexity means that improving sugarcane through conventional breeding is challenging. Because of this, researchers turn to gene editing tools, such as the CRISPR/Cas9 system to precisely target the sugarcane genome for improvement.

然而，作為紅甘蔗與野生甘蔗的雜交種。甘蔗具有所有作物中，最複雜的基因體。此複雜性意味著，透過傳統育種來改良甘蔗，具有挑戰性。因為這樣，研究人員們轉向諸如，CRISPR/Cas9(CRISPR：Clustered Regularly Interspaced Short Palindromic Repeat：群聚、規律性間隔開的短迴文結構複製)-( Cas9：CRISPR associated protein 9：CRISPR相關的蛋白質9)系統，來精確鎖定甘蔗基因體，以進行改良的基因編輯工具。

圖2. Eleanor Brant正在收集，供經基因編輯之甘蔗分子分析的葉子樣本。

Eleanor Brant collecting leaf samples for molecular analysis of gene-edited sugarcane.

In their new paper, published in Plant Biotechnology Journal, a team of researchers from the University of Florida at the Center for Advanced Bioenergy and Bioproducts Innovation (CABBI) has leveraged this genetic complexity to their advantage to use the CRISPR/Cas9 system to fine-tune leaf angle in sugarcane.

在他們發表於《植物生物技術雜誌》的新論文中，一支來自美國佛羅里達大學，於先進生物能源暨生物產物創新中心(CABBI)的研究人員們，已經借助其該種遺傳複雜性的優勢，來使用CRISPR/Cas9體系，以微調甘蔗的葉角。

These genetic tweaks allowed the sugarcane to capture more sunlight, which in turn increased the amount of biomass produced.

這些遺傳的調整使甘蔗得以捕捉更多的陽光，依序增加了產生的生物量。

This work supports the DOE-funded CABBI Bioenergy Research Center’s “plants as factories” approach and the primary goal of its Feedstock Production research — to synthesize biofuels, bioproducts, and high-value molecules directly in the stems of plants such as sugarcane.

該項研究支持了，美國能源部資助之CABBI生物能源研究中心“植物作為工廠”的方法，及其原料生產研究的主要目標，來於諸如甘蔗等植物的莖中，直接合成生物燃料、生物產物及高價值的分子。

The sugarcane genome’s complexity is due in part to its high levels of redundancy: It possesses many copies of each gene. The phenotype that a sugarcane plant displays, therefore, typically depends on the cumulative expression of the multiple copies of a certain gene. The CRISPR/Cas9 system is perfect for this task because it can be designed to edit a few or many copies of a gene at once.

甘蔗基因體的複雜性，部分由於其冗餘的高重複性水平：其具有每一基因的許多複製物。因此，甘蔗植物展示的表現型，通常取決於某一基因之多個複製物的累積表現。就此作業而言，CRISPR/Cas9體系是最適當的。因為，它能被設計來一次編輯，一個基因的幾個或多個複製物。

圖3. Baskaran Kannan於田間，評估經基因編輯的甘蔗

Baskaran Kannan evaluating gene-edited sugarcane in the field.

This study focused on LIGULELESS1, or LG1, a gene that plays a major role in determining leaf angle in sugarcane. Leaf angle, in turn, determines how much light can be captured by the plant, which is critical for biomass production.

該項研究著重於，在決定甘蔗葉角上，扮演一種重要角色的基因─LIGULELESS1(即LG1)。依序，葉角決定​​植物能捕獲多少光線。這對生物質量的生產至關重要。

Since sugarcane’s highly redundant genome contains 40 copies of LG1, the researchers were able to fine-tune the leaf angle by editing different numbers of copies of this gene, resulting in slightly different leaf angles depending on how many copies of LG1 were edited.

由於，甘蔗高度冗餘的基因體具有40份LG1的複製物。藉由編輯不同數量的此基因複製物，此些研究人員能微調葉角。取決於LG1 被編輯的多少複製物，會導致稍為不同的葉角。

“In some of the LG1 edited sugarcanes, we just mutated a few of the copies,” said Fredy Altpeter, research team lead and Professor of Agronomy at the University of Florida. “And in doing so, we were able to tailor the leaf architecture until we found the optimal angle that resulted in increased biomass yield.”

該研究團隊領導人，佛羅里達大學農學教授，Fredy Altpeter宣稱：「在一些 LG1 經編輯的甘蔗中，我們僅使其中少數複製物突變。結果，在這樣做的過程中，我們能夠訂製葉子結構，直到我們找到，導致生物量產量增加的最佳角度。」

When the scientists grew sugarcane in field trials, they found that the upright leaf phenotypes allowed more light to penetrate the canopy, which resulted in increased biomass yield. One sugarcane line in particular, which contained edits in ~12% of the LG1 copies and showed a 56% decrease in leaf inclination angle, had an 18% increase in dry biomass yield.

當此些科學家於田間試驗中種植甘蔗時，他們發現直立的葉子表現型使更多的光線得以穿透交錯的頂蓋，而導致增加的生物量產量。特別是一種，具有了在LG1 複製物約12%的編輯，且在葉片傾斜角上，展現了減少56%的甘蔗種系，在乾生物量的產量增加了18%。

By optimizing sugarcane to capture more light, these gene edits increase biomass yield without having to add more fertilizer to the fields. In addition to that, building a stronger understanding of complex genetics and genome editing helps researchers work toward refined approaches for crop improvement.

藉由最佳化甘蔗來捕獲更多的陽光，無需將更多肥料添加到此些田地中，此些基因編輯增加了生物質量的產量。除那之外，更加強有關複雜之遺傳學和基因體編輯的瞭解，有助於研究人員們致力於，改善作物的改良方法。

“This is the first peer-reviewed publication describing a field trial of CRISPR-edited sugarcane,” Altpeter said. “And this work also shows unique opportunities for the editing of polyploid crop genomes, where researchers can fine-tune a specific trait.”

Altpeter宣稱：「這是描述，經CRISPR編輯之甘蔗田間試驗，經同行評審的首度發表。同時，這項研究也證實了，有關該研究人員們能微調特定特徵之多倍體(一種生物體細胞具有多於一對(同源)染色體的情況)作物基因體編輯的獨特機會。」

網址：https://scitechdaily.com/scientists-use-crispr-to-turn-sugarcane-into-a-super-crop/

翻譯：許東榮