Different strategies to optimize the inoculation of potato plants with Methylobacterium sp. 2A

EDGAR MARTINEZ MOYANO; CECILIA EUGENIA MARÍA GROSSI; GITMAN, IVAN F.B.; RITA M. ULLOA

Rosario

Congreso; RAFV Conference 2023 XXXIV Argentinian Meeting of Plant Physiology; 2023

SAFV

A plant growth-promoting rhizobacteria (PGPR) belonging to the genusMethylobacterium was isolated from roots of potato plants. This PGPR, namedMethylobacterium sp. 2A, enhanced the growth of Arabidopsis and potato in vitro plantsexposed to salt conditions, antagonized plant pathogens and reduced disease symptomsin potato plants infected with Phytophthora infestans (Grossi et al., 2020). We aim tounderstand if the inoculation of Methylobacterium sp. 2A enhances plant defense inpotato plants through an induced systemic resistance (ISR) or by direct antagonism withthe pathogen. To this end, we employed three inoculation strategies using a suspensionof Methylobacterium sp. 2A cells (0.05 OD 600 units in 0.85% NaCl) or only 0.85% NaCl(control): i) roots of plants grown in solid MS for 3 weeks were inoculated with 100 µlof the suspension. Inoculated plants and controls were multiplied three consecutivetimes using internodes from the upper portion of the plants and the presence ofMethylobacterium was checked; ii) plants grown in solid MS for 3 weeks weretransferred to liquid MS for 24 h and then roots were inoculated with 0.8 ml of thesuspension and harvested at 3-, 10-, and 13-days post inoculation (dpi). The presence ofMethylobacterium in the liquid media was checked; iii) plants grown in solid MS for 3weeks were transferred to liquid MS for 24 h and then inoculated with 0.8 ml of thesuspension. At 8 dpi, plants were transferred to pots and placed in the greenhouse. Twoweeks later, Methylobacterium was recovered from a leaf extract of inoculated plantsand plant growth was evaluated in each condition. Plants had a better fitness inhydroponics and the growth promotion was evident in inoculated plants. P. infestansinfection assays will be conducted on plants inoculated using the three differentstrategies to evaluate ISR.