Finding the Biological Roots of a Virus That Ruins Maize Crops

Finding the Biological Roots of a Virus That Ruins Maize Crops
A severe form of maize streak virus in Africa and Asia may have formed from two mostly harmless viruses in grass. Scientists hope knowing this will help point to a cure. Transcript of radio broadcast.
15 September 2008

This is the VOA Special English Agriculture Report.

The maize streak virus causes one of the most destructive crop diseases in Africa. Not only is it economically damaging, it can also threaten food security. Maize crop failures lead to hunger in some areas. Maize streak disease also strikes parts of Asia.

Small insects known as leafhoppers carry the virus from field to field. Not much food can come from a field badly infected with the virus. The maize plants cannot produce a healthy cob. The disease gets its name from the streaks of yellow and white that discolor the leaves.

There are many less harmful kinds of maize streak virus. These cause minor infections in crops like sugarcane and wheat. But only one kind causes the most severe form of maize streak disease.

Researchers have been working to understand how this form of the virus got started and spread. They studied eighty versions of maize streak virus. They found that the severe kind may have formed from a recombination of less harmful grass viruses. In the process of recombination, the parent viruses exchanged a gene.

The study compared the genome of the maize streak virus with those of ten related but less harmful viruses. A genome contains all the information about an organism, including information carried from its parent organisms.

The most severe virus may have formed more than a century ago, when two mostly harmless viruses that infect wild grass combined.

Darren Martin of the University of Cape Town in South Africa led the research. He says the researchers found that every maize streak virus that severely affects maize came from an ancestral virus. That ancestral virus was the recombinant result of the two comparatively harmless viruses.

But the virus they formed was stronger. It could infect more plants than its parents. It could live through winters in wild grasses better than its relations. The researchers believe that this quality also made the severe form of maize streak virus spread faster.

Scientists from several parts of the world took part in the study, which appeared in the Journal of General Virology. The research continues. The goal is to find more biological information that could help lead to a cure.

And that's the VOA Special English Agriculture Report, written by Jerilyn Watson. For more reports -- with transcripts, MP3s and podcasts -- go to voaspecialenglish.com. I'm Steve Ember.

----------------------------Google Translate

寻找生物的根源，一个病毒的废墟玉米作物
一个严峻的形式，玉米条纹病毒在非洲和亚洲可能已经形成了从两个无害的病毒大多是在基层。科学家希望知道，这将有助于点到治愈。全文电台广播。
2008年9月15日

这是美国之音特别英语农业的报告。

玉米条纹病毒的原因之一，最具破坏性的作物病害是在非洲。它不仅是经济损害，它也可以威胁到粮食安全。玉米歉收导致饥饿在一些地区。玉米条纹病也罢工，亚洲部分地区。

小昆虫称为叶蝉进行病毒从野外到外地。没有太大的食物可以来自一个领域的严重感染禽流感病毒。该玉米植株不能产生一个健康的芯。疾病得名，从条纹的黄色和白色表示，变色的叶子。

有很多不足的有害种玉米条纹病毒。这些造成轻微感染的作物一样，甘蔗和小麦。但只有一种原因，最严重形式的玉米条纹病。

研究人员一直在努力了解如何在这种形式的病毒的起步和蔓延。他们研究了80版本的玉米条纹病毒。他们发现，严重的一种可能已经形成了从重组的危害较小的基层病毒。在这个过程中的重组，母公司病毒交换基因。

研究比较基因组的玉米条纹病毒与那些十相关，但较少有害的病毒。基因组包含的所有信息在一个生物体，包括信息进行从母公司的有机体。

最严重的病毒可能已经形成了一个多世纪前，当两大部分无害的病毒感染野草的总和。

戴伦李柱铭的大学，南非开普敦的领导这项研究的。他说，研究人员发现，每一个玉米条纹病毒，严重影响玉米来自一个祖先的病毒。认为祖先的病毒是重组的结果，这两个相对无害的病毒。

但该病毒，他们形成了较强。它可以感染更多的植物，比它的父母。它可以渡过冬天在野生草优于关系。研究者认为，这质量也发了言的严重形式的玉米条纹病毒蔓延的速度更快。

科学家从世界若干地区参加了这项研究，这似乎在Journal of一般病毒学。研究仍在继续。目标是要找到更多生物信息学可以帮助导致治愈。

这是该美国之音特别英语农业的报告，书面，由jerilyn沃森。更多报告-与誊本， M P3和播客-去v o aspecialenglish.com。我史蒂夫ember 。