Citrus sickness solved

Scientists in the US have used genetic techniques to solve a murder mystery - in citrus trees. Trees in Florida have been suffering from a disease called citrus greening, or Huonglongbing, which causes severe damage to leaves and fruit, eventually killing the tree. And it seems to be spreading, threatening the US' multi-billion dollar citrus industry.

The disease is caused by bacteria, which are spread by little insects. But previous research had shown that the bacteria weren't carrying poisonous toxins, so how they caused the disease was a mystery. Using genetic technology, the scientists analysed the patterns of gene activity in infected and non-infected trees, and found that the bacteria caused changes that interfered with nutrient transport and production. They also interfere with the production of plant hormones, which are important for growth and fruiting. The team hopes that their findings will lead to better tests to pick up the disease at an earlier stage, so it can be prevented from spreading further. And there's hope that they might be able to develop some kind of treatment to help the trees that have already caught the bug.