Assessment of affinity and specificity of Azospirillum for plants

• Published in: Plant and soil Vol. 399; no. 1-2; pp. 389 - 414
• Main Authors: Pereg, Lily, de-Bashan, Luz E, Bashan, Yoav
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.02.2016; Springer; Springer Nature B.V
• Subjects: Agricultural soils; Azospirillum; Azospirillum brasilense; Bacteria; Biomedical and Life Sciences; Cereals; Cultivars; Ecology; genotype; grain crops; grains; Health aspects; Host-bacteria relationships; Life Sciences; Observations; Plant growth; plant growth-promoting rhizobacteria; Plant interaction; Plant Physiology; Plant roots; Plant Sciences; Plant species; Plant-soil relationships; Plants; Proteobacteria; REVIEW ARTICLE; screening; Soil inoculation; Soil Science & Conservation; Studies; Wheat soils; Affinity; Specificity; Attachment; Colonization
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-015-2778-9

BACKGROUND: Azospirillum spp. are the most studied plant growth-promoting bacteria (PGPB). The genus represents a common model for plant-bacteria interactions. This genus was initially isolated and tested on cereals and was subsequently commercialized. AIMS: Despite claims of plant specificity, particularly towards cereals, data over the past 40 years does not appear to substantiate claims of such specificity/affinity of Azospirillum species. Consequently an evaluation of the specificity/affinity of the genus Azospirillum across all plants, in general, and cereals, in particular, was undertaken. RESULTS: Although the majority of studies focused on cereals, Azospirillum spp. increase growth of 113 plant species across 35 botanical families, including 14 species of cereals. Amongst Azospirillum spp., several well studied strains have been effective in several plant species, making these organisms potentially valuable for further study. CONCLUSIONS: This review demonstrates that azospirilla are not cereal-specific at the genus and species levels. Azospirillum serves as a general PGPB to every plant species tested so far. Given the paucity of widespread screening, affinity of strains to a plant genotype, cultivar, or plant species cannot be overruled. Definitive conclusions concerning such specificity require molecular and cross-inoculation studies, using various strains of bacteria, and re-isolation after growth of the plants in different plant species. (203 words).