Compatible bacterial mixture, tolerant to desiccation, improves maize plant growth

PLoS One. 2017 Nov 8;12(11):e0187913. doi: 10.1371/journal.pone.0187913. eCollection 2017.

Abstract

Plant growth-promoting rhizobacteria (PGPR) increase plant growth and crop productivity. The inoculation of plants with a bacterial mixture (consortium) apparently provides greater benefits to plant growth than inoculation with a single bacterial strain. In the present work, a bacterial consortium was formulated containing four compatible and desiccation-tolerant strains with potential as PGPR. The formulation had one moderately (Pseudomonas putida KT2440) and three highly desiccation-tolerant (Sphingomonas sp. OF178, Azospirillum brasilense Sp7 and Acinetobacter sp. EMM02) strains. The four bacterial strains were able to adhere to seeds and colonize the rhizosphere of plants when applied in both mono-inoculation and multi-inoculation treatments, showing that they can also coexist without antagonistic effects in association with plants. The effects of the bacterial consortium on the growth of blue maize were evaluated. Seeds inoculated with either individual bacterial strains or the bacterial consortium were subjected to two experimental conditions before sowing: normal hydration or desiccation. In general, inoculation with the bacterial consortium increased the shoot and root dry weight, plant height and plant diameter compared to the non-inoculated control or mono-inoculation treatments. The bacterial consortium formulated in this work had greater benefits for blue maize plants even when the inoculated seeds underwent desiccation stress before germination, making this formulation attractive for future field applications.

MeSH terms

  • Acinetobacter / physiology
  • Azospirillum brasilense / physiology
  • Biomass
  • Crops, Agricultural / growth & development
  • Crops, Agricultural / microbiology*
  • Crops, Agricultural / physiology
  • Desiccation
  • Mexico
  • Microbial Consortia / physiology*
  • Plant Development / physiology*
  • Plant Roots / growth & development
  • Plant Roots / microbiology*
  • Plant Roots / physiology
  • Pseudomonas putida / physiology
  • Rhizosphere
  • Seeds / growth & development
  • Seeds / microbiology*
  • Seeds / physiology
  • Sphingomonas / physiology
  • Symbiosis
  • Zea mays / growth & development
  • Zea mays / microbiology*
  • Zea mays / physiology

Grants and funding

The work was supported by the following: Apoyo Redes PRODEP 2015-2016 (CA-262 and CA-244); Ciencia Básica CONACYT CB2010-156576-Z; DITCo2016-3, DITCo2016-4; and VIEP-BUAP-2016 (00450, 00513, 00476, 00510). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.