Long Hoa Hoang, PhD

Personal Data:
Country of Origin: Vietnam
PhD period: January 2007 - October 2009

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

Project Leader: Prof. Dr. Ian T. Baldwin

Abstract:
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.

Publications:

• Long HH, Sonntag DG, Schmidt D, 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 Phytologist 185(2), 554-567.
• Widjaja I, Lassowskat I, Bethke G, Eschen-Lippold L, Long HH, Naumann K, Dangl J, Scheel D, Lee J (2010) A protein phosphatase 2C, responsive to the bacterial effector AvrRpm1 but not to the AvrB effector, regulates defense responses in Arabidopsis. The Plant Journal 61(3), 249-258.
• Long HH, 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.
• Long HH, Furuya N, Kurose D, Yamamoto I, Takeshita M, Takanami Y (2004) Identification of the endophytic bacterial isolates and their in vitro and in vivo antagonism against Ralstonia solanacearum. J Fac Agr Kyushu Univ 49(2), 233-241.
• Long HH, Furuya N, Kurose D, Takeshita M, Takanami Y (2003) Isolation of endophytic bacteria from Solanum sp. and their antibacterial activity against plant pathogenic bacteria. J Fac Agr Kyushu Univ 48 (1-2), 21-28.