Candidatus Liberibacter is a genus of gram-negative bacteria in the Rhizobiaceae

Rhizobiaceae

The Rhizobiaceae are a family of proteobacteria, including many species of rhizobia as well as plant parasites like Agrobacterium. Rhizobiaceae are, like all Proteobacteria, gram-negative. They are aerobic and the cells are usually rod-shaped. Many species of the Rhizobiaceae are diazotrophs, they...

 family. The term Candidatus

Candidatus

Candidatus is in scientific classification a component of the taxonomic name for a bacterium that cannot be maintained in a Bacteriology Culture Collection. It is an interim taxonomic status for noncultivable organisms. An example would be "Candidatus Phytoplasma allocasuarinae"...

is used to indicate that it has not proved possible to maintain this bacterium in culture. Detection of the liberibacters is based on PCR amplification of their 16S rRNA gene

16S ribosomal RNA

16S ribosomal RNA is a component of the 30S subunit of prokaryotic ribosomes. It is approximately 1.5kb in length...

 with specific primers. Members of the genus are plant pathogens mostly transmitted by psyllids

Jumping plant louse

Psyllids or jumping plant lice are small plant-feeding insects that tend to be very host specific, i.e. they only feed on one plant species or feed on a few related plants...

. The genus was originally spelled Liberobacter.

Species

Named species include:

• Liberibacter africanus - Originating in Africa and a causal agent of huanglongbing, also known as citrus greening disease and vectored by the african citrus psyllid Tioza erytreae.
• Liberibacter americanus - A novel species from Brazil described in 2005 and associated with huanglongbing, also known as citrus greening disease and vectored by the Asian citrus psyllid Diaphorina citri
  Diaphorina citri
  The Asian citrus psyllid, Diaphorina citri, is a sap-sucking, hemipteran bug in the family, Psyllidae. It is an important pest of citrus being one of only two known vectors of the serious citrus disease, Huanglongbing or greening disease. It is widely distributed in southern Asia and has spread to...
  
  .
• Liberibacter asiaticus - Originating in Asia and a causal agent of huanglongbing, also known as citrus greening disease and vectored by the Asian citrus psyllid Diaphorina citri
  Diaphorina citri
  The Asian citrus psyllid, Diaphorina citri, is a sap-sucking, hemipteran bug in the family, Psyllidae. It is an important pest of citrus being one of only two known vectors of the serious citrus disease, Huanglongbing or greening disease. It is widely distributed in southern Asia and has spread to...
  
  .
• Liberibacter europaeus - A novel species described in 2010, found in pear
  Pear
  The pear is any of several tree species of genus Pyrus and also the name of the pomaceous fruit of these trees. Several species of pear are valued by humans for their edible fruit, but the fruit of other species is small, hard, and astringent....
  
   trees where it seems to cause no symptoms and vectored by the psyllid
  Jumping plant louse
  Psyllids or jumping plant lice are small plant-feeding insects that tend to be very host specific, i.e. they only feed on one plant species or feed on a few related plants...
  
  , Cacopsylla pyri.
• Liberibacter psyllaurous - A novel species described in 2008 from solanaceous host plants potato
  Potato
  The potato is a starchy, tuberous crop from the perennial Solanum tuberosum of the Solanaceae family . The word potato may refer to the plant itself as well as the edible tuber. In the region of the Andes, there are some other closely related cultivated potato species...
  
   and tomato
  Tomato
  The word "tomato" may refer to the plant or the edible, typically red, fruit which it bears. Originating in South America, the tomato was spread around the world following the Spanish colonization of the Americas, and its many varieties are now widely grown, often in greenhouses in cooler...
  
   and vectored by the potato tomato psyllid
  Jumping plant louse
  Psyllids or jumping plant lice are small plant-feeding insects that tend to be very host specific, i.e. they only feed on one plant species or feed on a few related plants...
  
   (TPP), Bactericera cockerelli
  Bactericera cockerelli
  Bactericera cockerelli, also known as the potato psyllid, is a potato/tomato psyllid native to southern North America. As its name suggests, it is commonly found on potato and tomato crops, where feeding of the nymphs causes a condition called psyllid yellows, presumed to be the result of a...
  
  .
• Liberibacter solanacearum - A causal agent of zebra chip disease
  Zebra chip
  Zebra chip, also known as papa manchada and papa rayada, is the term for both an as-of-yet unidentified pathogen and the disease it causes in potatoes and their derivative products. Potato chips exposed to the Zebra chip pathogen develop unsightly black lines resembling the stripes of zebras that...
  
   in potato
  Potato
  The potato is a starchy, tuberous crop from the perennial Solanum tuberosum of the Solanaceae family . The word potato may refer to the plant itself as well as the edible tuber. In the region of the Andes, there are some other closely related cultivated potato species...
  
  es and vectored by the potato tomato psyllid
  Jumping plant louse
  Psyllids or jumping plant lice are small plant-feeding insects that tend to be very host specific, i.e. they only feed on one plant species or feed on a few related plants...
  
   (TPP), Bactericera cockerelli
  Bactericera cockerelli
  Bactericera cockerelli, also known as the potato psyllid, is a potato/tomato psyllid native to southern North America. As its name suggests, it is commonly found on potato and tomato crops, where feeding of the nymphs causes a condition called psyllid yellows, presumed to be the result of a...
  
  . This synonym is more often used in preference to "psyllaurous". The 16s sequences deposited in Genbank are identical
  

The commonly used abbreviations are Laf, Lam, Las, Leu and Lso.