香蕉能抵御致命的真菌嗎?

香蕉能抵御致命的真菌嗎?

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.

世界上最受歡迎的香蕉——卡文迪什香蕉品種——正受到一種真菌的威脅，這種真菌正在全球迅速蔓延。以前僅限于亞洲和澳大利亞部分地區(qū)的香蕉真菌，也被稱為巴拿馬病，也出現(xiàn)在中東和更多的南亞地區(qū)。

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.

現(xiàn)在這種真菌已經(jīng)蔓延到了拉丁美洲——這是專家們長期以來擔(dān)心的事情，這可能會對全球市場造成災(zāi)難性的影響，因為卡文迪什香蕉的大部分生長在那里。據(jù)《自然》雜志報道，8月初，哥倫比亞農(nóng)業(yè)研究所宣布全國進入緊急狀態(tài)，確認(rèn)該國北部的種植園發(fā)現(xiàn)了這種真菌。為了阻止疫情蔓延，農(nóng)作物被毀，種植園被隔離。

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.”

行業(yè)分析人士說，卡文迪什的日子不多了，但這可能不會很快發(fā)生?；裟匪固氐路鹆_里達(dá)大學(xué)的植物病理學(xué)家Randy Ploetz告訴《自然》雜志:“這些流行病發(fā)展緩慢，所以(傳播)需要一些時間。”“但最終，將不可能為國際貿(mào)易生產(chǎn)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——鐮孢鐮刀菌——在土壤中扎根，幾乎不可能被消滅。沒有人確切知道這種真菌是如何到達(dá)這些新地區(qū)的，但一些人認(rèn)為它可能是隨著從亞洲來到這些國家在當(dāng)?shù)胤N植園工作的移民工人而來的。

A tangled tale

一個糾結(jié)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.

香蕉具有悠久的歷史與各種Foc真菌。早在20世紀(jì)50年代，一種不同的香蕉品種幾乎消滅了一度流行的大麥克香蕉細(xì)菌。這種特殊的菌株對取代格羅·米歇爾的卡文迪什香蕉并不構(gòu)成威脅，但它們對最新的菌株TR4很敏感，TR4已經(jīng)蔓延到拉丁美洲?？ㄎ牡鲜蚕憬都s占全球香蕉銷量的13%。其他品種可能不會受到這種真菌的威脅，但它的傳播會傷害全球農(nóng)民。

The hits keep on coming

這一形勢繼續(xù)發(fā)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脅。據(jù)《獨立報》報道，2013年，哥斯達(dá)黎加產(chǎn)值5億美元的香蕉產(chǎn)業(yè)受到粉虱和介殼蟲的襲擊，進入國家緊急狀態(tài)，影響了該國20%的農(nóng)作物。蟲子會在水果上留下污點，使它們無法銷售。昆蟲數(shù)量的增加被歸咎于氣候變化。

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.

據(jù)《科學(xué)警報》報道，2016年，加州大學(xué)戴維斯分校和荷蘭的研究人員對引起香蕉葉斑病的三種真菌的基因組進行了測序。葉斑病會劫持香蕉的免疫系統(tǒng)。這一最新消息再次引發(fā)了對香蕉的可怕預(yù)測，因為這種疾病也成功地控制了香蕉的新陳代謝。

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，這條新聞也有其積極的一面:揭示了香蕉葉斑岡工作原理的基因組測序，可能還有助于科學(xué)家培育出抗病品種的香蕉。