Evaluation of growth and motility in non-photosynthetic Azospirillum brasilense exposed to red, blue, and white light

• Published in: Archives of microbiology Vol. 202; no. 5; pp. 1193 - 1201
• Main Authors: Romina, Molina, Gastón, López, Belén, Rodríguez, Susana, Rosas, Verónica, Mora, Fabricio, Cassán
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.07.2020; Springer Nature B.V
• Subjects: Azospirillum brasilense; Biochemistry; Biomedical and Life Sciences; Biotechnology; Cell Biology; Culture media; Ecology; Exposure; Inoculation; Life Sciences; Microbial Ecology; Microbiology; Motility; Original Paper; Photosynthesis; Plant growth; Swimming; Swimming behavior; White light; Red light; Swimming motility; Bacterial growth; White light; Blue light; Non-photosynthetic rhizobacteria; Azospirillum
• ISSN: 0302-8933; 1432-072X
• DOI: 10.1007/s00203-020-01829-8

Azospirillum brasilense is a non-photosynthetic rhizobacterium that promotes the growth of plants. In this work, we evaluated the effects of different light qualities on the growth, viability, and motility in combination to other culture conditions such as temperature or composition of the culture medium. Exponential cultures of A. brasilense Az39 were inoculated by drop-plate method on nutritionally rich (LB) or chemically defined (MMAB) media in the presence or absence of Congo Red indicator (CR) and exposed continuously to white light (WL), blue light (BL), and red light (RL), or maintained in dark conditions (control). The exposure to BL or WL inhibited growth, mostly in LB medium at 36 °C. By contrast, the exposure to RL showed a similar behavior to the control. Swimming motility was inhibited by exposure to WL and BL, while exposure to RL caused only a slight reduction. The effects of WL and BL on plant growth-promoting rhizobacteria should be considered in the future as deleterious factors that could be manipulated to improve the functionality of foliar inoculants, as well as the bacterial effects on the leaf after inoculation.