Natural rice rhizospheric microbes suppress rice blast infections

BMC Plant Biology

Research Article

Harsh Bais¹  Emily Alff¹  Carla Spence²  Cameron Johnson³  Cassandra Ramos³  Venkatesan Sundaresan³  Nicole Donofrio⁴ 

[1] Delaware Biotechnology Institute, Newark, USA;Department of Plant and Soil Sciences, University of Delaware, Newark, USA;Department of Biological Sciences, University of Delaware, Newark, USA;Delaware Biotechnology Institute, Newark, USA;Department of Plant Biology, University of California, Davis, USA;Department of Plant and Soil Sciences, University of Delaware, Newark, USA;

关键词: Rice;    Blast;    Magnaporthe oryzae;    Psuedomonas;    Hydrogen cyanide (HCN);    Biocontrol;    Induced systemic resistance;   

DOI  :  10.1186/1471-2229-14-130

 received in 2014-01-13, accepted in 2014-04-28,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundThe natural interactions between plant roots and their rhizospheric microbiome are vital to plant fitness, modulating both growth promotion and disease suppression. In rice (Oryza sativa), a globally important food crop, as much as 30% of yields are lost due to blast disease caused by fungal pathogen Magnaporthe oryzae. Capitalizing on the abilities of naturally occurring rice soil bacteria to reduce M. oryzae infections could provide a sustainable solution to reduce the amount of crops lost to blast disease.ResultsNaturally occurring root-associated rhizospheric bacteria were isolated from California field grown rice plants (M-104), eleven of which were taxonomically identified by16S rRNA gene sequencing and fatty acid methyl ester (FAME) analysis. Bacterial isolates were tested for biocontrol activity against the devastating foliar rice fungal pathogen, M. oryzae pathovar 70–15. In vitro, a Pseudomonas isolate, EA105, displayed antibiosis through reducing appressoria formation by nearly 90% as well as directly inhibiting fungal growth by 76%. Although hydrogen cyanide (HCN) is a volatile commonly produced by biocontrol pseudomonads, the activity of EA105 seems to be independent of its HCN production. During in planta experiments, EA105 reduced the number of blast lesions formed by 33% and Pantoea agglomerans isolate, EA106 by 46%. Our data also show both EA105 and EA106 trigger jasmonic acid (JA) and ethylene (ET) dependent induced systemic resistance (ISR) response in rice.ConclusionsOut of 11 bacteria isolated from rice soil, pseudomonad EA105 most effectively inhibited the growth and appressoria formation of M. oryzae through a mechanism that is independent of cyanide production. In addition to direct antagonism, EA105 also appears to trigger ISR in rice plants through a mechanism that is dependent on JA and ET signaling, ultimately resulting in fewer blast lesions. The application of native bacteria as biocontrol agents in combination with current disease protection strategies could aid in global food security.

【 授权许可】

Unknown   
© Spence et al.; licensee BioMed Central Ltd. 2014. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.