BayCEER Workshop 2023

Priming of horticultural tomato plants through minor stress applications as a protection strategy against biotic stressors

In nature, plants are constantly subject to environmental changes and biotic attacks. To act against these influences, they have developed passive (e.g. cuticle and cell wall) and inducible defense systems that are activated in the presence of stress factors. One kind of induced resistance response of plants is priming. Priming is the increased resistance of plants against subsequent stress. Mechanistically, it may depend on some genetic and epigenetic changes in defense genes. So, in our project as a part of a hortiprimed project, the main goal is to investigate if applying abiotic stress priming on tomato plants will enhance their resistance against subsequent biotic stresses.

For this purpose, we applied salinity stress with different scenarios, intensities, and durations to identify optimal priming conditions. After a recovery time, fungal infection (Alternaria alternata) on the control and primed plants was applied to evaluate the result of plant resistance against subsequent stress.

The effect of salt stress priming on the defense response of plants was assessed by lesion size caused by subsequent infection with A alternata. As a result, we observed a significant difference between the lesion size of control and primed plants 4 days and even 17 days after priming. when we consider the lesion development of the pathogen over time (from 4 days to 17 days), we observed that the lesion size decreased over time. Moreover, the significant difference between the lesion size of the control, 100 and 200 mM primed plants was observed. 

In summary, different concentrations of salt solution as abiotic priming had a significant effect on the defense response of the primed plants which was evaluated by leaf lesion size. Moreover, leaf lesion size development which was caused by the fungal pathogen decreased over time.