Abstract:
By colonizing plant organs and thereby living in a relationship with their hosts, microbial plant symbionts can support plant growth and health. The rhizosphere is a rather well studied environment whereas the phyllosphere has not been in scientists’ focus to the same extent. A group of bacteria, the Paraburkholderia are known for being able to establish lasting symbioses with diverse groups of plants.
When our work group found a novel species belonging to this genus – namely Paraburkholderia dioscoreae strain Msb3 – on the leaf acumen of the tropical yam plant Dioscorea bulbifera, we were interested in finding out about its potential as a plant growth promoting symbiont living in the phyllosphere of its host. Since its genetic repertoire seemed very promising, the main objective was testing whether Msb3 could colonize plants other than its natural hosts, discover the underlying processes of colonization and reveal if it could actually provide a benefit to their fitness.
By inoculating seedlings of Lycopersicum esculentum – better known as tomato – with Msb3 cells in several settings, we could find localization patterns within the rhizosphere as well as in the phyllosphere via FISH and CLSM. Quantitative PCR revealed that it could establish higher cell numbers within both environments than its close relative Paraburkholderia phytofirmans strain PsJN, a well-studied plant symbiont with a wide range of hosts. Most importantly, we were able to prove that after a growth period of six weeks, Msb3 inoculated plants were significantly heavier than plants that were inoculated with PsJN cells or dead Msb3 cells and therefore there must be a biological plant growth promotion conferred by Paraburkholderia dioscoreae.
Corresponding Paper
The potato yam phyllosphere ectosymbiont Paraburkholderia sp. Msb3 is a potent growth promotor in tomato JB Herpell, F Schindler, M Bejtović, L Fragner, B Diallo, A Bellaire, ... Frontiers in Microbiology 11, 525875 18 2020
Phyllosphere symbiont promotes plant growth through ACC deaminase production JB Herpell, A Alickovic, B Diallo, F Schindler, W Weckwerth The ISME Journal 17 (8), 1267-1277
