香蕉能抵御致命的真菌吗?

The world's most popular bananas — the Cavendish cultivar variety — have come under threat from a fungus that's rapidly spreading around the world. Previously constrained to parts of Asia and Australia, the banana fungus, also known as Panama disease, has also appeared in the Middle East and more of South Asia.

世界上最受欢迎的香蕉——卡文迪什香蕉品种——正受到一种真菌的威胁，这种真菌正在全球迅速蔓延。以前仅限于亚洲和澳大利亚部分地区的香蕉真菌，也被称为巴拿马病，也出现在中东和更多的南亚地区。

The global banana industry is substantial, but it's mostly focused one type — Cavendish — which are vulnerable to disease because they are all clones that originate from the same plant. (Photo: Suthat Chaithaweesap/Shutterstock)

Now the fungus has spread to Latin America — something experts had long feared, which could be disastrous for the worldwide market because that's where the majority of Cavendish bananas are grown. In early August, the Colombian Agricultural Institute announced a national state of emergency, confirming that the fungus had been found in plantations in the north of the country, reports Nature. In an attempt to stop the spread, crops were destroyed and plantations quarantined.

现在这种真菌已经蔓延到了拉丁美洲——这是专家们长期以来担心的事情，这可能会对全球市场造成灾难性的影响，因为卡文迪什香蕉的大部分生长在那里。据《自然》杂志报道，8月初，哥伦比亚农业研究所宣布全国进入紧急状态，确认该国北部的种植园发现了这种真菌。为了阻止疫情蔓延，农作物被毁，种植园被隔离。

Industry analysts say the Cavendish's days are numbered, but it likely won't happen soon. “These epidemics develop slowly, so the [spread] will take some time,” Randy Ploetz, a plant pathologist at the University of Florida in Homestead, told Nature. “But eventually, it will not be possible to produce Cavendish for international trade.”

行业分析人士说，卡文迪什的日子不多了，但这可能不会很快发生。霍姆斯特德佛罗里达大学的植物病理学家Randy Ploetz告诉《自然》杂志:“这些流行病发展缓慢，所以(传播)需要一些时间。”“但最终，将不可能为国际贸易生产卡文迪什。”

Once the fungus — Fusarium oxysporum f. sp.cubense, more commonly referred to as Foc — takes hold in the soil, it's almost impossible to eliminate. No one knows exactly how the fungus arrived in these new areas, but some people think it could have arrived with migrant workers who came to the countries from Asia to work on local plantations.

一旦真菌——镰孢镰刀菌——在土壤中扎根，几乎不可能被消灭。没有人确切知道这种真菌是如何到达这些新地区的，但一些人认为它可能是随着从亚洲来到这些国家在当地种植园工作的移民工人而来的。

A tangled tale

一个纠结的故事

Bananas have a long history with varieties of the Foc fungus. A different strain all but wiped out the once-popular Gros Michel banana cultivar back in the 1950s. That particular strain is not a threat to Cavendish bananas, which replaced Gros Michel, but they are susceptible to the newest strain, called TR4, which is the one that has spread to Latin America. Cavendish bananas represent about 13% of worldwide banana sales. Other varieties may not be at risk from the fungus, but its spread would hurt farmers across the globe.

香蕉具有悠久的历史与各种Foc真菌。早在20世纪50年代，一种不同的香蕉品种几乎消灭了一度流行的大麦克香蕉细菌。这种特殊的菌株对取代格罗·米歇尔的卡文迪什香蕉并不构成威胁，但它们对最新的菌株TR4很敏感，TR4已经蔓延到拉丁美洲。卡文迪什香蕉约占全球香蕉销量的13%。其他品种可能不会受到这种真菌的威胁，但它的传播会伤害全球农民。

The hits keep on coming

这一形势继续发展

The fungus is not the only threat to bananas. In 2013, Costa Rica's $500 million banana industry was in a state of national emergency, according to the Independent, after being hit by mealybugs and scale insects, which affected as much as 20% of the country's crop. The bugs cause blemishes on the fruits, making them unsellable. The increased insect population was blamed on climate change.

真菌并不是香蕉的唯一威胁。据《独立报》报道，2013年，哥斯达黎加产值5亿美元的香蕉产业受到粉虱和介壳虫的袭击，进入国家紧急状态，影响了该国20%的农作物。虫子会在水果上留下污点，使它们无法销售。昆虫数量的增加被归咎于气候变化。

In 2016, researchers from the University of California, Davis and the Netherlands sequenced the genomes of three strains of fungus that cause Sigatoka, which hijacks the bananas immune system, according to Science Alert. The update prompted a renewal of dire predictions for bananas as we know them today because this disease has also managed to manipulate the bananas' metabolism.

据《科学警报》报道，2016年，加州大学戴维斯分校和荷兰的研究人员对引起香蕉叶斑病的三种真菌的基因组进行了测序。叶斑病会劫持香蕉的免疫系统。这一最新消息再次引发了对香蕉的可怕预测，因为这种疾病也成功地控制了香蕉的新陈代谢。

Oddly enough, there's an upside to the news: The genome sequencing that uncovered how Sigatoka works may also help scientists create disease-resistant varieties of bananas.

奇怪的是，这条新闻也有其积极的一面:揭示了香蕉叶斑冈工作原理的基因组测序，可能还有助于科学家培育出抗病品种的香蕉。