The team uses the techniques of gene splicing to remove useful genes from extremophiles and add them to plants.
Designer Plants On Mars
Take the cold tolerance of bacteria that thrive in arctic ice, add the ultraviolet resistance of tomato plants growing high in the Andes mountains, and combine with an ordinary plant. What do you get? A tough plant "pioneer" that can grow in Martian soil.
Like customizing a car, NASA-funded scientists are designing plants that can survive the harsh conditions on Mars.
These plants could provide oxygen, fresh food, and even medicine to astronauts while living off their waste. They would also improve morale as a lush, green connection to Earth in a barren and alien world.
The research is being sponsored by the NASA Institute for Advanced Concepts (NIAC), which investigates revolutionary ideas that could greatly advance NASA's missions in the future.
The proposals push the limits of known science and technology, and thus are not expected to be realized for at least decade or more.
The plants would probably be housed in a greenhouse on a Martian base, because no known forms of life can survive direct exposure to the Martian surface, with its extremely cold, thin air and sterilizing radiation.
Even then, conditions in a Martian greenhouse would be beyond what ordinary plants could stand. During the day, the plants would have to endure high levels of solar ultraviolet radiation, because the thin Martian atmosphere has no ozone to block it like the Earth's atmosphere does.
At night, temperatures would drop well below freezing. Also, the Martian soil is poor in the mineral nutrients necessary for plants to thrive.
"Our idea is to enable plants to survive on Mars by adding features from microscopic organisms called extremophiles that live in the most inhospitable environments on Earth," said Dr. Wendy Boss of North Carolina State University.
Boss and her colleague, Dr. Amy Grunden, also of North Carolina State, head the research team working on this project.
The team uses the techniques of gene splicing to remove useful genes from extremophiles and add them to plants. (A gene is a molecular instruction that specifies a feature for an organism, such as eye color, height, the ability to digest certain foods or resist toxins, etc.)
The current NIAC funding pays for "proof of concept" work that demonstrates the feasibility of the team's idea and identifies the technical challenges that must be overcome for Martian plants to become a reality.
To prove their concept, the team took a gene from "Pyrococcus furiosus," a microbe that lives in the scalding water issuing from deep sea vents, and inserted it into a tobacco cells.
The gene, "superoxide reductase," removes toxic oxygen atoms and molecules that are generated in organisms under stress. The gene was successfully incorporated into the tobacco cells and functioned without harming them.
The team plans to transform plants with genes for cold tolerance as the next step in their research.
They also used their NIAC concept as an educational experience, giving undergraduate students at North Carolina State the challenge of selecting features from existing organisms that would be useful for Martian plants and designing ecosystems for Martian greenhouses.
"The features we are incorporating in Martian plants, like cold and drought tolerance, will also help crops bear severe weather here on Earth, so this work has practical application," said Grunden.
"This type of long-term research, with an uncertain path to success, is only possible with an organization like NIAC that doesn't mind taking a chance for the possibility of an incredible breakthrough," added Grunden.
NIAC was created in 1998 to solicit revolutionary concepts from people and organizations outside NASA. The Universities Space Research Association operates NIAC for NASA.
《太空日报》5月19日消息，让普通植物拥有细菌在极地环境下顽强生存的耐寒性，加上安第斯山脉高地番茄植物的抗紫外线性质，它会是什么样子？它会是一种能够生长在火星土壤中的顽强植物“先驱者”?！
美国宇航局先进理念研究所(NIAC)资助科学家们培植一种能够在火星恶劣环境下生存的植物。这些植物依靠宇航员们的排泄物生存，却能够提供氧气、新鲜的食物、甚至药品。它们和地球上绿色植物相似的外表，可能还会有助于激发人们在那个贫瘠世界奋斗的勇气。
先进理念研究所(NIAC)资助该项目的目的是研究出可以大大促进航空和宇宙航行局未来探险计划的创新设想。
因为他们的建议都临近科学与技术的极限，因此在最少十年内是不会实现的。
这种植物可能会生长在火星基地上的温室中，因为目前还没有哪种已知生物可以暴露在火星表面极度寒冷、空气稀薄以及高强度辐射的条件下仍能生存。
即使在未来，火星温室的条件也将是一般植物所无法生存的。白天，这些植物将承受高强度太阳紫外线照射，这是由于火星稀薄的大气不含有臭氧层来像地球一样阻挡紫外线；夜间，气温将降低到冰点一下。而且，火星的土壤也十分贫瘠，没有多少可以供植物生长的矿物质养分。
“我们的目的是利用被称为极端微生物（extremophiles）的有机微生物体为植物增加特性，使它们可以在地球上最恶劣的环境下生存。”北卡莱罗纳州立大学的温迪·波斯博士说。
波斯和她的同事，埃米·戈鲁登博士——同样来自北卡莱罗纳州立大学——共同负责这一研究项目。
她们的研究小组利用基因拼接方法从极端微生物中移走有用的基因然后拼接到植物中。（基因是用来指定有机物特性的分子指令，例如眼睛的颜色、身高、消化某种食物的能力、抗毒能力等等。）
先进理念研究所的资金目前用来进行“证实理论”方面的工作，来说服人们相信这一小组的设想是可行的，并且证明克服火星植物技术上的难题是可以实现的。
为了证明自己的理论，研究小组从火球菌（Pyrococcus furiosus）中提取了一种基因，这种细菌生存在深海火山口附近高温水中，然后把基因插入到烟草的细胞中。
这种基因，“过氧化物还原酶”，可以移除有机物在压力下释放出的有毒氧原子和分子。它不仅成功地合并到了烟草细胞中，而且在没有伤害细胞的情况下正常发挥作用。
这一小组计划下一步开始研究提取耐寒植物的基因。
研究小组也将先进理念研究所的设想教育化，为北卡莱罗纳州立大学的大学生们提供机会，让他们选择不同的有机物特性，来帮助火星植物的培植与火星温室生态系统的设计。
“我们所结合到火星植物中的这些特性，例如耐寒、耐旱等，也会帮助地球上的农作物可以承受更加恶劣的气候。所以我们的研究部分上来说，也是实用的。” 戈鲁登说。
“这样的长期研究往往并不确定是否会有所成效，它仅仅是先进理念研究所这样并不在意是否有可能研究出突破性的成果的机构才会进行的。” 戈鲁登补充说。
