Application of biochar reduces Ralstonia solanacearum infection via effects on pathogen chemotaxis, swarming motility, and root exudate adsorption

• Published in: Plant and soil Vol. 415; no. 1-2; pp. 269 - 281
• Main Authors: Gu, Yian, Hou, Yugang, Huang, Dapeng, Hao, Zhexia, Wang, Xiaofang, Wei, Zhong, Jousset, Alexandre, Tan, Shiyong, Xu, Dabing, Shen, Qirong, Xu, Yangchun, Friman, Ville-Petri
• Format: Journal Article
• Language: English
• Published: Cham Springer 01.06.2017; Springer International Publishing; Springer Nature B.V
• Subjects: Adsorption; Bacteria; Biomedical and Life Sciences; Charcoal; Chemotaxis; Colonization; Control methods; Disease control; Ecology; Exudates; Exudation; Greenhouses; Health aspects; Identification methods; In vitro testing; Incidence; Infections; Life Sciences; Measurement methods; Motility; Observations; Particle size; Pathogens; Plant Physiology; Plant Sciences; Proteobacteria; Regular Article; Rhizosphere; Soil microorganisms; Soil Science & Conservation; Swarming; Tomatoes; Virulence; Virulence factors; Wilt; Root exudate; Bacterial wilt; Adsorption; Biochar; Disease control
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-016-3159-8

Aims We evaluated the efficacy of biochar application for suppressing bacterial wilt of tomato and identified the potential underlying mechanisms involved in the disease control. Methods We measured the impact of two different sized biochar (53–120 μm and 380–830 μm) on bacterial wilt incidence in a greenhouse experiment. The efficiency of different sized biochar for the adsorption of tomato root exudates and the pathogen was further examined in vitro. We also quantified the effects of biochar and tomato root exudates on two pathogen virulence factors, chemotaxis, swarming motility and examined the effect of biochar on pathogen root colonization. Results Fine biochar application (3%; w:w) significantly decreased the bacterial wilt incidence by 19.9%. Biochar with different particle size had similar adsorption capacity for root exudates, while fine biochar was efficient (91%) in pathogen adsorption. Root exudates and fine biochar increased the chemotaxis ability of pathogen, while fine biochar reduced pathogen swarming motility and rhizosphere colonization. Conclusions Application of fine biochar can significantly decreased bacterial wilt incidence. This was mechanistically explained by biochar ability to 1) adsorb pathogen directly and indirectly via adsorption of root exudates (based on pathogen chemotaxis) and to 2) directly suppress pathogen swarming motility and sub-sequent root colonization.