Evolutionary origins of the potato revealed – and a tomato was involved
马铃薯进化起源揭晓——番茄竟是关键参与者
WASHINGTON, Aug 1 (Reuters) – The potato is one of the world’s food staples, first cultivated thousands of years ago in the Andes region of South America before spreading globally from the 16th century. But despite its importance to humankind, the evolutionary origins of the potato have remained puzzling – until now.
路透华盛顿 8 月 1 日电 – 马铃薯是世界主要粮食作物之一，数千年前首次在南美洲安第斯地区被栽培，16 世纪后开始全球传播。尽管对人类至关重要，但马铃薯的进化起源一直是个谜团——直到现在。
A new analysis of 450 genomes from cultivated potatoes and 56 genomes of wild potato species has revealed that the potato lineage originated through natural interbreeding between a wild tomato plant and a potato-like species in South America about 9 million years ago.
对 450 个栽培马铃薯基因组和 56 个野生马铃薯物种基因组的新分析表明，马铃薯谱系起源于约 900 万年前南美洲一种野生番茄植物与类似马铃薯物种的自然杂交。
This hybridization event led to the appearance of the nascent potato plant’s tuber, an enlarged structure housing nutrients underground, according to the researchers, who also identified two crucial genes involved in tuber formation. Whereas in a tomato plant the edible part is the fruit, in the potato plant it is the tuber.
研究人员表示，这次杂交事件导致了新生马铃薯块茎的出现——这种膨大的地下结构储存着养分。研究还确定了两个参与块茎形成的关键基因。番茄的可食用部分是果实，而马铃薯的可食用部分则是块茎。
“Potatoes are truly one of humanity’s most remarkable food staples, combining extraordinary versatility, nutritional value and cultural ubiquity in ways few crops can match,” said Sanwen Huang, a genome biologist and plant breeder at the Chinese Academy of Agricultural Sciences and senior author of the study published on Friday in the journal Cell, opens new tab.
中国农业科学院基因组生物学家、植物育种专家黄三文表示：”马铃薯堪称人类最卓越的主食之一，其非凡的多样性、营养价值和文化普及性相结合的程度，是其他农作物难以企及的。”黄三文是周五发表在《细胞》期刊上这项研究的资深作者。
“People eat potatoes using virtually every cooking method – baking, roasting, boiling, steaming and frying. Despite being stereotyped as carbohydrates, potatoes offer vitamin C, potassium, fiber and resistant starch, and are naturally gluten-free, low-fat and satiating – a nutrient-dense calorie source,” Huang added.
黄三文补充道：”人们几乎运用了所有烹饪方式处理马铃薯——烘烤、煎炸、水煮、清蒸或油炸。尽管常被简单归类为碳水化合物，马铃薯其实富含维生素 C、钾元素、膳食纤维和抗性淀粉，天然不含麸质且脂肪含量低，既能提供饱腹感又是营养密集的热量来源。”
Resistant starch is a type of carbohydrate that resists digestion in the small intestine and ferments in the large intestine, feeding beneficial bacteria in the gut.
抗性淀粉是一种难以在小肠被消化，但能在大肠发酵的碳水化合物，可为肠道有益菌群提供养分。
The modern-day potato plant’s scientific name is Solanum tuberosum. Its two parents identified in the study were plants that were the ancestors of a potato-like species now found in Peru named Etuberosum, which closely resembles the potato plant but lacks a tuber, and the tomato plant.
现代马铃薯的学名为 Solanum tuberosum。研究确认其两个亲本植物分别是：现今秘鲁发现的类马铃薯物种 Etuberosum（形态酷似马铃薯但不结块茎）的祖先植株，以及番茄植株。
These two plants themselves shared a common ancestor that lived about 14 million years ago, and were able to naturally interbreed when the fortuitous hybridization event occurred five million years after they had diverged from each other.
这两种植物本身拥有约 1400 万年前的共同祖先，在彼此分化 500 万年后，当偶然的杂交事件发生时仍能自然杂交繁殖。
“This event led to a reshuffling of genes such that the new lineage produced tubers, allowing these plants to expand into the newly created cold, dry habitats in the rising Andes mountain chain,” said botanist Sandra Knapp of the Natural History Museum in London, a co-author of the study.
“这次事件导致基因重组，使得新谱系能够产生块茎，从而使这些植物得以扩张到安第斯山脉隆起过程中新形成的寒冷干旱栖息地，”该研究的合著者、伦敦自然历史博物馆植物学家桑德拉·纳普表示。
This hybridization event coincided with the rapid uplift of the Andes. With a tuber, the potato plant was able to adapt to the changing regional environment and thrive in the harsh conditions of the mountains.
这次杂交事件恰逢安第斯山脉的快速隆起。凭借块茎结构，马铃薯植株得以适应不断变化的区域环境，在山区恶劣条件下繁衍生息。
“Tubers can store nutrients for cold adaptation, and enable asexual reproduction to meet the challenge of the reduced fertility in cold conditions. These allowed the plant to survive and rapidly expand,” Huang said.
“块茎能够储存营养物质以适应寒冷，并通过无性繁殖来应对寒冷条件下生育力下降的挑战。这些特性使植株得以存活并快速扩张，”黄教授指出。
The study’s findings, according to the researchers, may help guide improved cultivated potato breeding to address environmental challenges that crops presently face due to factors such as climate change.
研究人员表示，这项研究的发现可能有助于指导改良栽培马铃薯的育种，以应对目前农作物因气候变化等因素面临的环境挑战。
There currently are roughly 5,000 potato varieties. The potato is the world’s third most important food crop, after rice and wheat, for human consumption, according to the Peru-based International Potato Center research organization. China is the world’s leading potato producer.
目前全球约有 5000 种马铃薯品种。根据总部位于秘鲁的国际马铃薯中心研究机构的数据，马铃薯是世界上仅次于水稻和小麦的第三大重要粮食作物。中国是全球最大的马铃薯生产国。
“It always is hard to remove all the deleterious mutations in potato genomes in breeding, and this study opens a new door to make a potato free of deleterious mutations using the tomato as the chassis of synthetic biology,” Huang said.
“在育种过程中彻底清除马铃薯基因组中的有害突变一直很困难，这项研究打开了一扇新大门——以番茄作为合成生物学载体，培育不含有害突变的马铃薯，”黄教授表示。
The study also may open the door to generate a new crop species that could produce tomato fruit above ground and potato tubers below ground, according to Zhiyang Zhang, a postdoctoral researcher at the Chinese Academy of Agricultural Sciences.
中国农业科学院博士后研究员张志阳表示，这项研究还可能为培育新型作物品种打开大门——这种作物能在地上结出番茄果实，同时在地下长出马铃薯块茎。
The potato and tomato are members of the nightshade family of flowering plants that also includes tobacco and peppers, among others. The study did not investigate the evolutionary origins of other tuberous root crops that originated in South America such as the sweet potato and yuca, which are members of different families of flowering plants.
马铃薯和番茄同属茄科开花植物，该科还包括烟草和辣椒等作物。这项研究并未探讨其他起源于南美洲的块根类作物（如甘薯和木薯）的进化起源，它们分属不同科的开花植物。
While the parts of the tomato and potato plants that people eat are quite different, the plants themselves are very similar.
虽然人们食用的番茄和马铃薯植株部位大不相同，但两种植物本身却极为相似。
“We use different parts of these two species, fruits in tomatoes and tubers in potatoes,” Knapp said. “If you look at the flowers or leaves, these are very similar. And if you are lucky enough to let your potato plant produce fruits, they look just like little green tomatoes. But don’t eat them. They are not very nice.”
“我们利用这两个物种的不同部位——番茄的果实和马铃薯的块茎，”克纳普说。”如果你观察它们的花或叶，会发现非常相似。要是运气好让马铃薯植株结出果实，它们看起来就像绿色的小番茄。但千万别吃，味道可不怎么样。”