Twenty years of paradigm-breaking studies of taxonomy and symbiotic nitrogen fixation by beta-rhizobia, and indication of Brazil as a hotspot of Paraburkholderia diversity

• Published in: Archives of microbiology Vol. 203; no. 8; pp. 4785 - 4803
• Main Authors: Paulitsch, Fabiane, dos Reis, Fabio Bueno, Hungria, Mariangela
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-10-2021; Springer Nature B.V
• Subjects: Agrochemicals; Ammonia; Archives & records; Bacteria; Biochemistry; Biomedical and Life Sciences; Biotechnology; Burkholderia; Cell Biology; Ecology; Genera; Legumes; Leguminous plants; Life Sciences; Microbial Ecology; Microbiology; Mini-Review; Nitrogen; Nitrogen fixation; Nitrogenation; Paraburkholderia; Prokaryotes; Symbiosis; Taxonomy; Brazil; Betarhizobia; Nodulation; BNF; Biological nitrogen fixation
• ISSN: 0302-8933; 1432-072X
• DOI: 10.1007/s00203-021-02466-5

Twenty years ago, the first members of the genus
Burkholderia
capable of nodulating and fixing N
2
during symbiosis with leguminous plants were reported. The discovery that β-proteobacteria could nodulate legumes represented a breakthrough event because, for over 100 years, it was thought that all rhizobia belonged exclusively to the α-Proteobacteria class. Over the past 20 years, efforts toward robust characterization of these bacteria with large-scale phylogenomic and taxonomic studies have led to the separation of clinically important and phytopathogenic members of
Burkholderia
from environmental ones, and the symbiotic nodulating species are now included in the genera
Paraburkholderia
and
Trinickia
.
Paraburkholderia
encompasses the vast majority of β-rhizobia and has been mostly found in South America and South Africa, presenting greater symbiotic affinity with native members of the families Mimosoideae and Papilionoideae, respectively. Being the main center of
Mimosa
spp. diversity, Brazil is also known as the center of symbiotic
Paraburkholderia
diversity. Of the 21 symbiotic
Paraburkholderia
species described to date, 11 have been isolated in Brazil, and others first isolated in different countries have also been found in this country. Additionally, besides the symbiotic N
2
-fixation capacity of some of its members,
Paraburkholderia
is considered rich in other beneficial interactions with plants and can promote growth through several direct and indirect mechanisms. Therefore, these bacteria can be considered biological resources employed as environmentally friendly alternatives that could reduce the agricultural dependence on agrochemical inputs.