Autophagy is an evolutionarily well-conserved cellular catabolic pathway in eukaryotic cells and plays an important role in cellular processes. Autophagy is regulated by autophagy-associated (ATG) proteins. Among these ATG proteins, the ubiquitin-like protein ATG8/LC3 is essential for autophagosome formation and function. In this study, the potato StATG8 family showed clade I and clade II with significantly different sequences. Expression of the StATG8 family was also increased in senescence. Interestingly, the expression of the StATG8 and other core StATG genes decreased in potato tubers as the tubers matured. The StATG8 family also responded to a variety of stresses such as heat, wounding, salicylic acid, and salt stress. We also found that some Arabidopsis WRKY transcription factors interacted with the StATG8 protein in planta. Based on group II-a WRKY, StATG8-WRKY interaction is independent of the ATG8 interacting motif (AIM) or LC3 interacting region (LIR) motif. This study showed that the StATG8 family had diverse functions in tuber maturation and multiple stress responses in potatoes. Additionally, StATG8 may have an unrelated autophagy function in the nucleus with the WRKY transcription factor.

Climate change adversely affects the water and temperature conditions required for plant growth, leading to a decrease in yield. In high temperatures, oxidative stress causes cellular damage in plant cells, which is a negative factor for crop production. Thioredoxin (Trx) is a small redox protein containing a conserved WC(G/P)PC motif that catalyzes the exchange of disulfide bonds. It is known to play an important role in maintaining cellular redox homeostasis. Trx proteins are widely distributed across various subcellular locations, and they play a crucial role in responding to cellular stresses. In this study, seven CaTrxh-type genes present in pepper were identified and the CaTrxh-type family was classified into three subgroups. CaTrxh genes responded to heat stress. Moreover, subcellular locations of the CaTrxh family exhibited dynamic patterns in normal conditions, and we observed relocalizations in heat stress conditions. Each CaTrxh family protein member formed homo-/heteromeric protein complexes in BiFC assay. Unexpectedly, subgroup III CaTrxh9 and CaTrxh10 can recruit subgroup I and II CaTrxh proteins into the plasma membrane. Thus, the function of the CaTrxh-type family is expected to play a protective role in the cell in response to high-temperature stress via protein complex formations. CaTrxh may have potential applications in the development of crops with enhanced tolerance to oxidative stress.

Plasma-activated water (PAW) has gained attention across agricultural, medical, cosmetic, and sterilization fields due to its production of reactive oxygen and nitrogen species (ROS and RNS). Although PAW has been primarily explored for seed germination and sterilization in agriculture, its role as a nutrient source and physiological regulator remains less understood. In this study, PAW generated by a surface dielectric barrier discharge (SDBD) system contained approximately 1000 ppm nitrate (NO₃⁻) and was designated as PAW1000. Diluted PAW solutions were applied to sprout crops—wheat (Triticum aestivum), barley (Hordeum vulgare), radish (Raphanus sativus), and broccoli (Brassica oleracea var. italica)—grown under hydroponic and soil-based conditions. PAW100 and PAW200 treatments enhanced growth, increasing fresh biomass by up to 26%, shoot length by 22%, and root length by 18%, depending on the species. In silico analysis identified nitrogen-responsive transcripts among several autophagy-related genes. Consistent with this, fluorescence microscopy of Arabidopsis thaliana GFP-StATG8 lines revealed increased autophagosome formation following PAW treatment. The growth-promoting effect of PAW was diminished in atg4 mutants, indicating that autophagy contributes to plant responses to PAW-derived ROS and RNS. Together, these findings demonstrate that diluted PAW generated by SDBD enhances biomass accumulation in sprout crops, and that autophagy plays a regulatory role in mediating PAW-induced physiological responses.