An efficient, high‐throughput method for the simultaneous exposure of drought stress and bacterial infection in plants

Abstract

We developed a systematic protocol for the easy, high-throughput, qualitative, and quantitative assessment of the patho-morphological, physiological, and molecular responses of Arabidopsis thaliana plants simultaneously subjected to drought and bacterial infection. This approach will assist studies elucidating plant adaptation strategies to combat combined stresses. METHODS AND RESULTS: Plants were grown in small screw-capped containers, individual pots, or pot strips. Watering was withheld from 30-day-old plants, which were subsequently infected with Pseudomonas syringae pv. tomato DC3000 using a dip inoculation. The natural development of both drought and bacterial infection was successfully and rapidly replicated in large numbers of plants, which is difficult to achieve with existing protocols. CONCLUSIONS: Our protocol offers a simple, low-cost, high-throughput strategy for the rapid and easy bacterial infection of large numbers of plants. It can be used in large-scale mutant and ecotype screenings under combined stresses and for other foliar pathogens in different plant species.

Drought attenuates plant defence against bacterial pathogens by suppressing the expression of CBP60g/SARD1 during combined stress

“…In 4 days, soil moisture status decreased from 100% FC to 60% FC, which is considered moderate drought stress for A. thaliana (Gupta, Rico‐Medina, et al, 2016; Ma et al, 2014). At 60% FC (34‐day‐old plants), 2% agarose solution was poured around the plants to further seal any remaining spaces (Choudhary & Senthil‐Kumar, 2020). The bacterial suspension (OD 600 0.01, 5 × 10 6 CFU/ml) was poured into a sterile container, and the surfactant Silwet L‐77 (Lehle Seeds, Fisher Scientific) was added to the suspension (0.01%).…”

“…Drought was initiated in 30‐day‐old plants grown under well‐watered conditions by withholding irrigation. The potting mix around the plants was covered using three to four thin rectangular plastic sheets to prevent the bacterial suspension from changing the water status of the potting mix (Choudhary & Senthil‐Kumar, 2020). The moisture status of the potting mix was measured by the gravimetric method (Ramegowda et al, 2013) and expressed as field capacity (FC; soil moisture content).…”