Title: Bacterial Production of Indole Related Compounds Reveals Their Role in Association Between Duckweeds and Endophytes

Abstract

Duckweed farming can be a sustainable practice for biofuel production, animal feed supplement, and wastewater treatment, although large scale production remains a challenge. Plant growth promoting bacteria (PGPB) have been shown to improve plant health by producing phytohormones such as auxin. While some of the mechanisms for plant growth promotion have been characterized in soil epiphytes, more work is necessary to understand how plants may select for bacterial endophytes that have the ability to provide an exogenous source of phytohormones such as auxin. We have isolated and characterized forty-seven potentially endophytic bacteria from surface-sterilized duckweed tissues and screened these bacterial strains for production of indole related compounds using the Salkowski colorimetric assay. Indole-3-acetic acid (IAA), indole-3-lactic acid (ILA), and indole produced by various bacterial isolates were verified by mass spectrometry. Using the Salkowski reagent, we found that 79% of the isolated bacterial strains from our collection may be capable of producing indole related compounds to various extents during in vitro growth. Of these bacteria that are producing indole related compounds, 19% are additionally producing indole. There is an apparent correlation between the type of indole related compound produced by a particular bacteria and the duckweed genus from which the bacterialmore » strain is derived. These results suggest the possible association between different duckweed genera and endophytes that are producing distinct types of secondary metabolites. Understanding the role of indole related compounds during interaction between endophytes and the plant host may be useful to help design synthetic bacterial communities that could target specific or multiple species of duckweed in the future to sustainably enhance plant growth.« less

Authors:

Gilbert, Sarah ^[1]; Xu, Jenny ^[1]; Acosta, Kenneth ^[1]; Poulev, Alexander ^[1]; Lebeis, Sarah ^[2]; Lam, Eric ^[1]

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+ Show Author Affiliations

1. Rutgers Univ., New Brunswick, NJ (United States). Dept. of Plant Biology
2. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Microbiology

Publication Date:

Thu Jul 12 00:00:00 EDT 2018

Research Org.:

Rutgers Univ., New Brunswick, NJ (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER)

OSTI Identifier:

1510429

Grant/Contract Number:  

SC0018244

Resource Type:

Accepted Manuscript

Journal Name:

Frontiers in Chemistry

Additional Journal Information:

Journal Volume: 6; Journal ID: ISSN 2296-2646

Publisher:

Frontiers Research Foundation

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES; auxin; Wolffia; duckweeds; indoles; Salkowski assay; endophytes