Long Hoa Hoang

Characterizing and analyzing the ecological consequences of the plant - endophyte interactions of Solanum nigrum and Nicotiana attenuata

Endophytic bacteria are defined as those living in plant tissues without doing any substantive harm or gaining benefit other than securing residency. Endophytic bacteria can promote plant growth and health by different mechanisms. These include the production of phytohormones or enzymes involved in growth regulator metabolism such as ethylene, 1-aminocyclopropane-1-carboxylic acid deaminase, auxins, or cytokinins. Endophytic bacteria, thus, play important roles in modulating responses of plants to these regulators. Solanum nigrum and Nicotiana attenuata are two native Solanaceous species which have been used as model systems for studying plant-herbivore interactions. Signaling compounds such as jasmonic acid (JA), ethylene and salicylic acid (SA) involved in the responses of these plants to the herbivore and pathogen attacks have been well studied. Effects of plant growth promoting rhizobacteria (PGPR) including endophytic bacteria on ethylene signaling in some plant species such as canola (Brassica campestris cv. Reward), sugarcane (Saccharum sp.), and Arabidopsis sp. have been reported. However, effects caused by endophytic bacteria on the two native plants S. nigrum and N. attenuata have not been studied. Therefore, this study aims to investigate the specific responses of these plants to colonization of beneficial endophytic bacteria and to identify the key elements that control the dynamic interaction of plant and endophyte.


Meldau DG, Meldau S, Hoang LH, Underberg S, Wünsche H, Baldwin IT (2013) Dimethyl disulfide produced by the naturally associated bacterium bacillus sp B55 promotes Nicotiana attenuata growth by enhancing sulfur nutrition. Plant Cell 25(7), 2731-2747. Details PubMed

Meldau DG, Hoang HL, Baldwin IT (2012) A native plant growth promoting bacterium, Bacillus sp. B55, rescues growth performance of an ethylene-insensitive plant genotype in nature. Front Plant Sci 3, 112. Details PubMed

Hoang HL, Sonntag DG, Schmidt DD, Baldwin IT (2010) The structure of the culturable root bacterial endophyte community of Nicotiana attenuata is organized by soil composition and host plant ethylene production and perception. New Phytol 185(2), 554-567. Details PubMed

Hoang HL, Schmidt DD, Baldwin IT (2008) Native bacterial endophytes promote host growth in a species-specific manner; phytohormone manipulations do not result in common growth responses. PLoS One 3(7), e2702. Details PubMed


Ian T. Baldwin

Start of PhD

January 1, 2007

Doctoral Disputation

October 28, 2009

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