ROLE OF THE CHROMATIN REMODELER MOM1 IN THE PRIMING AGAINST PATHOGENS IN Arabidopsis thaliana (L.) HEYNH.

MIRANDA DE LA TORRE JO; ALVAREZ ME; CECCHINI NM

Congreso; IV REUNIÓN CONJUNTA DE SOCIEDADES DE BIOLOGÍA DE LA REPÚBLICA ARGENTINA; 2020

After recognition of a pathogen, plants induce local and distal defenses. Systemic resistance programs are usually associated with animmune alertness, immunological "memory" or priming. Despite not showing constitutive defenses, a primed plant responds faster and/orstrongly to recurrent infections. Priming may involve an increase in immune receptors, accumulation of inactive signaling proteins and/orepigenetic modifications of chromatin that predispose to transcriptional activation of defense genes. The chromatin remodeler "MorpheusMolecule" (MOM1) was recently proposed as a priming factor associated with the activation of defenses during aging. Here, we analyzedthe role of MOM1 in the immunological "memory" of Arabidopsis. We studied the susceptibility of mom1 mutant plants to chemical andbiological inducers of priming against pathogens. We also determined whether the increased pathogen resistance observed in plants lackingMOM1 is caused by aging and/or growth conditions. We found that, independently of the development stage, under optimal conditions ofgrowth and sterility mom1 mutant plants show increased levels of immune receptors without the induction of defenses. In addition, mom1is more sensible to the priming inducers azelaic acid (AZA) and aminobutyric acid (BABA). Consistently, transgenic plants that express aminimal but functional version of MOM1 (mini-MOM1) do not respond to these inductors. Moreover, treatments with AZA or BABAreduced the transcript levels of MOM1 in wild-type plants. Together, our results position the chromatin remodeler MOM1 as a negativeregulator of the priming against pathogens in Arabidopsis.