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

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.

Diversity and Plant Growth Promoting Ability of Culturable Endophytic Bacteria in Nepalese Sweet Potato

“…The inoculation of crop plants with beneficial microbes is a practice used in agriculture and provides advantages to crops by enhancing plant growth and triggering protection to diseases [55]. It was also reported that the inoculation with multiple beneficial bacteria have higher potential than inoculation with a single bacterial inoculant [12] [64]. Our study also showed the positive effects when the isolates were applied as a mixture from each location.…”

“…In this study, we aimed to examine bacterial community of sweet potato endophytes in Nepal in relation to the environmental parameters and characterize their plant growth promoting traits. As synergistic effect of mixed cultures of plant growth promoting bacteria was reported [11] [12], we also examined their potential by inoculating combined isolates from each location.…”

Efficient colonization of the endophytes Herbaspirillum huttiense RCA24 and Enterobacter cloacae RCA25 influences the physiological parameters of Oryza sativa L. cv. Baldo rice

“…In recent years, a large deal of literature has been produced on co-inoculation (consortium) of agriculturally beneficial microorganisms and in many cases benefits have been observed compared with the single inoculation (Akintokun and Taiwo, 2016;Sahu et al, 2016;Molina-Romero et al, 2017;Lally et al, 2017;Orozco-Mosqueda et al, 2018;Sahu et al, 2018). The present study shows that the beneficial endophytes E. cloacae RCA25 and H. huttiense RCA24 can be promising strains to improve, directly or indirectly, nitrogen fixation in rice plants under greenhouse conditions.…”

Multistrain versus single-strain plant growth promoting microbial inoculants - The compatibility issue

“…In many cases, the outcome of the in vitro co-culture compatibility tests reflects the actual nature of the interaction to some extent (Prasad and Subramanian, 2017). For example, competitive colonization assays under controlled, greenhouse or fi eld conditions demonstrated that in vitro compatible bacterial and/or fungal stains are also compatible in the rhizosphere; root population levels reached by each strain in the mixture were not signifi cantly diff erent from those obtained when strains were applied individually (Agusti et al, 2011;Alizadeh et al, 2013;Stefanic et al, 2015;Castanheira et al, 2017;Molina-Romero et al, 2017;Santiago et al, 2017). The same goes with in vitro incompatible combinations.…”