This study evaluated 12 Bacillus strains for their ability to promote plant growth in corn, wheat, and soybean. In greenhouse experiments, several Bacillus strains significantly increased root growth in all three crops by up to 154% compared to the control. In laboratory experiments, the Bacillus strains exhibited multiple plant growth-promoting traits like phosphate solubilization, indole acetic acid production, and siderophore activity. While the strains showed different in vitro physiological profiles, their growth promotion potentials in plants were not dependent on the specific traits exhibited. The results indicate that Bacillus has potential for improving crop productivity through various direct and indirect mechanisms of action.

1. Bacillus strains for plant growth-promotion of corn, wheat, and soybean
Introduction
Methods
 Growth promotion assessment.
Observations
Results - growth promotion
Citations
1.Adesemoye, A. O., & Ugoji, E. O. (2009). Evaluating Pseudomonas aeruginosa as plant growth-promoting
rhizobacteria in West Africa. Archives of Phytopathology and Plant Protection, 42(2), 188-200.
2.Ahemad, M., & Kibret, M. (2014). Mechanisms and applications of plant growth promoting rhizobacteria: current
perspective. Journal of King Saud University-Science, 26(1), 1-20..
3.Kloepper, J. W., Schroth, M. N., & Miller, T. D. (1980). Effects of rhizosphere colonization by plant growth-promoting
rhizobacteria on potato plant development and yield. Phytopathology, 70(11), 1078-1082.
4.Kumar, A., Prakash, A., & Johri, B. N. (2011). Bacillus as PGPR in crop ecosystem. In Bacteria in agrobiology: crop
ecosystems (pp. 37-59). Springer, Berlin, Heidelberg.
5.Recep, K., Fikrettin, S., Erkol, D., & Cafer, E. (2009). Biological control of the potato dry rot caused by Fusarium
species using PGPR strains. Biological Control, 50(2), 194-198.
6.Yuen, G. Y., Godoy, G., Steadman, J. R., Kerr, E. D., & Craig, M. L. (1991). Epiphytic colonization of dry edible bean
by bacteria antagonistic to Sclerotinia sclerotiorum and potential for biological control of white mold disease. Biological
Control, 1(4), 293-301.
Plant growth-promoting rhizobacteria (PGPR) have potential to
increase plant growth via direct or indirect mechanisms (1;2;6).
Both mechanisms may involves the exhibition of one or more
plant growth promotion related physiological traits. Several
bacteria genera are recognized with PGPR activity, but Bacillus,
Burkoldhera and Pseudomonas are most studied as PGPR (5).
Among all PGPR, bacillus – the endospore-forming, Gram-
positive bacteria - are most attractive. Their cells can survive
under harsh environmental conditions because of their stress-
tolerant endospores. The attribute also elongate shelf life of
bacillus cells in formulations. These qualities make bacillus
PGPR more attractive to many researchers (4). Therefore in this
study, 12 bacillus strains belonging to the genera Bacillus,
Paenibacillus and Lysinibacillus from wheat rhizosphere in
Nebraska, were evaluated for plant growth-promotion potentials
in greenhouse and laboratory experiments.
Objectives
1.To identify strain that can increase growth on corn, soybean,
and wheat plants.
2.To relate strains’ growth promotion efficacy to their in vitro
physiological traits.
R. Akinrinlola, G. Yuen, and T. Adesemoye.
Department of Plant Pathology, University of Nebraska-Lincoln.
Fig. 1. Strains (A, B, and C) increased corn root growth compared
to control (D).
Fig. 2. Strains (R180, R181 and KPS46) increased corn seedling
root numbers and size compared to control (PB).
AcknowledgementThis study was a part of the Multistate Research Project W3147: Managing Plant-Microbe Interactions in Soil to Promote Sustainable Agriculture.
Funding was provided by Agricultural Research Division, Institute of Agriculture and natural resources, University of Nebraska- Lincoln
Seed treatment Seed sowing Data collection at 20 days
Phosphate
solubilization
Indole acetic
acid production
Siderophore
activity
Direct plant growth
in pouches.
Antibiosis Chitinase ProteaseBiosurfactant
 Traits assessment.
Negative
Control
KPS46 R180 R181
A B
C D
Results:-
Bacillus strains increased soybean root growth significantly, up to 144%
compared to control (Fig. 4).
Fig.4. Effects of bacillus strains on soybean root growth
Fig. 5. Effects of bacillus strains on wheat root growth
Results:-
Bacillus strains increased wheat root growth significantly, up to 154%
compared to control (Fig. 5).
 Bacillus strains increased corn root growth significantly, up to
154% compared to control (Fig. 1 and 3).
Fig.3. Effects of bacillus strains on corn root growth
Fig. 6. Plant growth promotion-related traits exhibited by bacillus strains in vitro.
Results – traits assessment.
 Bacillus strains exhibited multiple strains
 Most strains positive for direct mechanisms – proteolysis, IAA and pouch
assay (Fig. 6.)
Conclusions
Bacillus has potentials for improving crop productivity.
Bacillus has broad mechanisms of action.
Growth promotion potentials of bacillus strains are not
dependent on the physiological traits exhibited in vitro.
Screening of potential PGPR is best conducted by pot exp.