Citrus greening (or Huonglongbing or yellow dragon disease) is a bacterial infection caused by
Candidatus liberibacter. The disease interferes with starch and sugar metabolism in young and matures leaves and fruit, ruining the crop and eventually killing the tree. The disease causes causing yellowing of shoots, blotchy and mottled leaves, lopsided and poorly-colored fruit and loss of viable seeds.
Whilst citrus greening remains incurable once a tree becomes heavily infected, plant scientist have
used DNA sequencing technologies to show how citrus greening impacts trees before they show signs of infection. The aim is to develop tests that allow the infection to be detected so that actions can be taken to save the trees before it is too late.
The scientists have had some success in pinpointing genetic changes in a newly infected tree. It is hoped that this will become the basis of a diagnostic test.
The disease has spread across the U.S. in recent years. The main vector for spreading the contamination is infected leaves which blow from an infected tree to a non-infected tree. The disease has
now killed millions of citrus plants in the southeastern United States and is threatening to spread across the entire country.
The research was carried out at University of California, Davis. The findings have been
reported in the journal PLOS ONE. The paper is titled “Gene Regulatory Networks Elucidating Huanglongbing Disease Mechanisms.”
