Low-temperature atmospheric pressure plasma has been used in various fields such as plasma medicine, agriculture, food safety and storage, and food manufacturing. In the field of plasma agriculture, plasma treatment improves seed germination, plant growth, and resistance to abiotic and biotic stresses, allows pesticide removal, and enhances biomass and yield. Currently, the complex molecular mechanisms of plasma treatment in plasma agriculture are fully unexplored, especially those related to seed germination and plant growth. Therefore, in this review, we have summarized the current progress in the application of the plasma treatment technique in plants, including plasma treatment methods, physical and chemical effects, and the molecular mechanism underlying the effects of low-temperature plasma treatment. Additionally, we have discussed the interactions between plasma and seed germination that occur through seed coat modification, reactive species, seed sterilization, heat, and UV radiation in correlation with molecular phenomena, including transcriptional and epigenetic regulation. This review aims to present the mechanisms underlying the effects of plasma treatment and to discuss the potential applications of plasma as a powerful tool, priming agent, elicitor or inducer, and disinfectant in the future.

Summary: Indeterminate domain(IDD) genes are a family of plant transcriptional regulators that function in the control of development and metabolism during growth. Here, the function ofOryza sativa indeterminate domain 10(OsIDD10) has been explored in rice plants. Compared with wild‐type roots,idd10mutant roots are hypersensitive to exogenous ammonium. This work aims to define the action ofIDD10on gene expression involved in ammonium uptake and nitrogen (N) metabolism. The ammonium induction of key ammonium uptake and assimilation genes was examined in the roots ofidd10mutants andIDD10overexpressors. Molecular studies and transcriptome analysis were performed to identify target genes and IDD10 bindingcis‐elements. IDD10 activates the transcription ofAMT1;2andGDH2by binding to acis‐element motif present in the promoter region ofAMT1;2and in the fifth intron ofGDH2. IDD10 contributes significantly to the induction of several genes involved inN‐linked metabolic and cellular responses, including genes encoding glutamine synthetase 2, nitrite reductases and trehalose‐6‐phosphate synthase. Furthermore, the possibility that IDD10 might influence the N‐mediated feedback regulation of target genes was examined. This study demonstrates that IDD10 is involved in regulatory circuits that determine N‐mediated gene expression in plant roots.

Lamina inclination is a key agronomical character that determines plant architecture and is sensitive to auxin and brassinosteroids (BRs). Loose Plant Architecture1 (LPA1) in rice (Oryza sativa) and its Arabidopsis homologues (SGR5/AtIDD15) have been reported to control plant architecture and auxin homeostasis. This study explores the role of LPA1 in determining lamina inclination in rice. LPA1 acts as a positive regulator to suppress lamina bending. Genetic and biochemical data indicate that LPA1 suppresses the auxin signalling that interacts with C-22-hydroxylated and 6-deoxo BRs, which regulates lamina inclination independently of OsBRI1. Mutant lpa1 plants are hypersensitive to indole-3-acetic acid (IAA) during the lamina inclination response, which is suppressed by the brassinazole (Brz) inhibitor of C-22 hydroxylase involved in BR synthesis. A strong synergic effect is detected between lpa1 and d2 (the defective mutant for catalysis of C-23-hydroxylated BRs) during IAA-mediated lamina inclination. No significant interaction between LPA1 and OsBRI1 was identified. The lpa1 mutant is sensitive to C-22-hydroxylated and 6-deoxo BRs in the d61-1 (rice BRI1 mutant) background. We present evidence verifying that two independent pathways function via either BRs or BRI1 to determine IAA-mediated lamina inclination in rice. RNA sequencing analysis and qRT-PCR indicate that LPA1 influences the expression of three OsPIN genes (OsPIN1a, OsPIN1c and OsPIN3a), which suggests that auxin flux might be an important factor in LPA1-mediated lamina inclination in rice.

Low-temperature atmospheric pressure plasma technology has been used in agriculture and plant science by direct and indirect treatment of bio-samples. However, the cellular and molecular mechanisms affected by plasma-activated water (PAW) are largely unexplored. In this study, PAW generated from a surface dielectric barrier discharge (SDBD) device was used for plant development. Physicochemical analysis was performed to confirm the PAW properties that correlated with the plasma treatment time. Arabidopsis thaliana L. was utilized to study the effect of the PAW treatment in the early developmental stage. The plasma-activated water samples are denoted as PAW5 time in minutes (min), PAW7 min, PAW12 min, PAW19 min and PAW40 min with the plasma treatment time. Seedlings grown in the PAW5, PAW7 and PAW12 had increased root lengths while the root lengths were decreased in the PAW19 and PAW40. In the cellular level observation, the PAW treatment specifically increased the root hair numbers per unit of the root but suppressed the root hair length in the PAW, indicating that PAW mainly modulates the root hair cell density in the root. Furthermore, we found that the root hair density and length at PAW5 in maximal observed conditions were positively regulated by root developmental-related genes including COBRA-LIKE9 (COBL9), XYLOGLUCAN ENDOTRANSGLUCOSYLASE/HYDROLASE9 (XTH9), XTH17, AUXIN1 (AUX1) and LIKE-AUXIN (LAX3).