Agronomy 2013, 3(4), 595-620; doi:10.3390/agronomy3040595
Article

Bacillus simplex—A Little Known PGPB with Anti-Fungal Activity—Alters Pea Legume Root Architecture and Nodule Morphology When Coinoculated with Rhizobium leguminosarum bv. viciae

1 Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA 90095-1606, USA 2 School of Biological Sciences, University of Waikato, Hamilton 3240, New Zealand 3 Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095-1489, USA 4 Department of Botany and Plant Sciences, University of California, Riverside, CA 91521, USA 5 Molecular Biology Institute, University of California, Los Angeles, CA 90095-1570, USA These authors contributed equally to this work.
* Author to whom correspondence should be addressed.
Received: 21 June 2013; in revised form: 29 August 2013 / Accepted: 13 September 2013 / Published: 26 September 2013
PDF Full-text Download PDF Full-Text [1588 KB, uploaded 26 September 2013 12:25 CEST]
Abstract: Two strains, 30N-5 and 30VD-1, identified as Bacillus simplex and B. subtilis, were isolated from the rhizospheres of two different plants, a Podocarpus and a palm, respectively, growing in the University of California, Los Angeles (UCLA) Mildred E. Mathias Botanical Garden. B. subtilis is a well-known plant-growth promoting bacterial species, but B. simplex is not. B. simplex 30N-5 was initially isolated on a nitrogen-free medium, but no evidence for nitrogen fixation was found. Nevertheless, pea plants inoculated with B. simplex showed a change in root architecture due to the emergence of more lateral roots. When Pisum sativum carrying a DR5::GUSA construct, an indicator for auxin response, was inoculated with either B. simplex 30N-5 or its symbiont Rhizobium leguminosarum bv. viciae 128C53, GUS expression in the roots was increased over the uninoculated controls. Moreover, when pea roots were coinoculated with either B. simplex 30N-5 or B. subtilis 30VD-1 and R. leguminosarum bv. viciae 128C53, the nodules were larger, clustered, and developed more highly branched vascular bundles. Besides producing siderophores and solubilizing phosphate, the two Bacillus spp., especially strain 30VD-1, exhibited anti-fungal activity towards Fusarium. Our data show that combining nodulating, nitrogen-fixing rhizobia with growth-promoting bacteria enhances plant development and strongly supports a coinoculation strategy to improve nitrogen fixation, increase biomass, and establish greater resistance to fungal disease.
Keywords: anti-fungal activity; lateral roots; nodulation; plant growth-promoting bacteria; phosphate solubilization; siderophores

Article Statistics

Load and display the download statistics.

Citations to this Article

Cite This Article

MDPI and ACS Style

Schwartz, A.R.; Ortiz, I.; Maymon, M.; Herbold, C.W.; Fujishige, N.A.; Vijanderan, J.A.; Villella, W.; Hanamoto, K.; Diener, A.; Sanders, E.R.; DeMason, D.A.; Hirsch, A.M. Bacillus simplex—A Little Known PGPB with Anti-Fungal Activity—Alters Pea Legume Root Architecture and Nodule Morphology When Coinoculated with Rhizobium leguminosarum bv. viciae. Agronomy 2013, 3, 595-620.

AMA Style

Schwartz AR, Ortiz I, Maymon M, Herbold CW, Fujishige NA, Vijanderan JA, Villella W, Hanamoto K, Diener A, Sanders ER, DeMason DA, Hirsch AM. Bacillus simplex—A Little Known PGPB with Anti-Fungal Activity—Alters Pea Legume Root Architecture and Nodule Morphology When Coinoculated with Rhizobium leguminosarum bv. viciae. Agronomy. 2013; 3(4):595-620.

Chicago/Turabian Style

Schwartz, Allison R.; Ortiz, Irma; Maymon, Maskit; Herbold, Craig W.; Fujishige, Nancy A.; Vijanderan, Janahan A.; Villella, William; Hanamoto, Kayoko; Diener, Andrew; Sanders, Erin R.; DeMason, Darleen A.; Hirsch, Ann M. 2013. "Bacillus simplex—A Little Known PGPB with Anti-Fungal Activity—Alters Pea Legume Root Architecture and Nodule Morphology When Coinoculated with Rhizobium leguminosarum bv. viciae." Agronomy 3, no. 4: 595-620.

Agronomy EISSN 2073-4395 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert