Thermopriming-Induced Autophagy in Shoot Apical Meristem of Arabidopsis

BACKGROUND: Since embryogenesis, plants deal with environmental changes, which might affect their growth and development. Plant autophagy has been shown to function in various stress responses, immunity, development, and senescence. Acquired thermotolerance or thermopriming is enhanced resistance to the elevated temperature following heat stress. OBJECTIVES: Potential contribution of autophagy mechanism after thermopriming was investigated in shoot apical meristem (SAM) of Arabidopsis thaliana. MATERIALS AND METHODS: Transcriptic expression of Autophagy related Genes (ATGs) were analyzed by qRT-PCR data in 5-day old Arabidopsis thaliana (Col0) seedlings at 4 h and 24 h after thermopriming. Autophagy induction was confirmed by confocal microscopy. RESULTS: Expression patterns of 39 ATGs and ATG-receptors were described and relevant thermopriming induced autophagy genes were identified according to their highest expression fold changes during the time after treatment. Significantly, ATG8A, ATG8B, ATG8G, ATG8H, ATI1, ATI2, NBR1, and TSPO genes were identified as the most relevant thermopriming-associated autophagy genes especially in SAM of young seedlings. This mainly implies the role of ATG8 core proteins and their receptor interactors in the regulation of autophagy in form of selective or non-selective during environmental stresses. CONCLUSIONS: Autophagy, a conserved mechanism for cell survival in plants will be activated in response to the thermopriming which is a promoted acquired resistance stimulus. Determined key genes and components of autophagy associated with thermal priming signaling pathway could be noteworthily employed to study transcriptional regulation of autophagy and integrated defense system against environmental stresses for the improvement of plant thermal tolerance and resistance to the pathogens.