Researchers from Boyce Thompson Institute (BTI) and the USDA Agricultural
Research Service (USDA-ARS) found new clues about how the bacteria linked to
citrus greening infect the only insect that carries them which could lead to
finding the solution on how to block the spread of infection. The results
are published in Infection and Immunity.
Citrus greening (a.k.a. huanglongbing) is a major problem in citrus
production worldwide. Infected trees are unable to get enough nutrients from
the soil, their leaves turn yellow, young twigs die back, and fruit remains
small and green, which is not suitable for sale. Eventually, the tress die
completely. These symptoms are linked to a bacterium (Candidatus
Liberibacter asiaticus or CLas) which is spread by an insect vector called
Asian citrus psyllid. Several strategies have been employed by citrus
growers to control the disease but none has been proven to be effective in
BTI professor and USDA-ARS researcher Michelle Heck and team aimed at
developing a long-term solution by focusing on an important point: not all
psyllids are equal in their ability to spread the disease. Previous studies
have shown that nymphs are better than adults in terms of acquiring the
bacteria from trees. Heck also previously found out that the adults's gut
cells go through a severe stress response during CLas infection, leading to
disruption of cell nuclei. In the recent study, they found out that nymphs
rarely reached the same level of nuclei disruption observed in adults.
The next step of Heck's team is to identify the mechanism for resistance in
the nymphs so that it might be reversed to stop the spread of CLas.