Yinyuan Wen

The RING-type E3 ubiquitin ligase plays a significant role in plant responses and adaptations to abiotic stresses such as drought. However, few studies have explored the role of E3 ubiquitin ligases in potato drought stress, especially DRIP1. In this study, 172 StHCa genes were identified across the potato genome. These genes were unevenly distributed on twelve chromosomes and divided into six subclades (group I–VI). The molecular weight of potato HCa proteins ranges from 5445.38 to 143,293.69 Da. More than half of them are acidic proteins and most are unstable. There are 161 hydrophilic proteins, and the subcellular localization analysis indicated that they were mainly located in the nucleus. The co-linearity analysis of StHCa genes showed that 172 genes underwent 40 tandem duplications and 28 segmental duplication events. Potato and tomato share a recent common ancestor and exhibit highly similar evolutionary trajectories. Promoter sequence analysis of the StHCa family identified abundant cis-acting elements associated with light signal transduction, hormone responses, plant growth and development, and abiotic stress responses. These results suggest that the StHCa genes may play important regulatory roles in different environmental signals and developmental stages. Expression profiling revealed that StDRIP1 exhibited higher transcript levels in potato roots than in stems and leaves, and its expression was significantly induced by drought stress. Physiological phenotyping demonstrated that StDRIP1-overexpressing (OE) plants displayed reduced root growth compared with wild-type (WT) plants, with decreases in root length, total root area, total root volume, and root vitality. Under 20% PEG-6000-simulated drought stress, the root expression level of StDRIP1 was higher in OE lines than in WT plants. Furthermore, StDRIP1 overexpression suppressed the activities of antioxidant enzymes (POD, CAT, and SOD) and weakened their osmotic adjustment ability by reducing proline (Pro) accumulation. At the late stage of stress treatment (9 h), the SOD, POD, and CAT activities of OE plants were 5.0%, 19.9%, and 25.1% lower than those of WT plants, respectively. These physiological alterations exacerbated oxidative damage, as evidenced by increased malondialdehyde (MDA) content and elevated electrolyte leakage in OE plants. In summary, this study comprehensively characterized the StHCa gene family in potato, providing a valuable theoretical basis for elucidating the functional mechanism of StDRIP1 in modulating drought stress responses. Collectively, StDRIP1 acts as a negative regulator of potato drought tolerance through two primary mechanisms: (1) repressing root growth and weakening root vitality, thereby reducing the water absorption capacity of roots; and (2) diminishing antioxidant enzyme activities and impairing osmotic homeostasis, which further exacerbates oxidative damage under drought stress.

Potatoes are typically seeded as tubers, and their slow sprouting significantly impacts production. Therefore, the effects of polyacrylamide (20 g·L⁻¹, 30 g·L⁻¹, and 40 g·L⁻¹) as a seed potato dressing on sprouting, seedling growth, and biomass were investigated. The phytohormone content, respiratory intensity, and starch metabolism enzyme activity were analyzed to elucidate the physiological mechanisms involved. The sprouting rate significantly increased after 20 g·L⁻¹ and 30 g·L⁻¹ treatments by 40.63% and 15.63%, respectively. The sprouting energy was the highest (52.0%) at 20 g·L⁻¹, 7.67 times higher than the control. The 20 g·L⁻¹ and 30 g·L⁻¹ treatments also promoted emergence and growth, with the emergence rate increasing by 18.18% and 27.27% and growth increasing by over 8.1% and 11.9%, respectively. These effects were related to changes in phytohormone content and accelerated starch conversion. After treatment, the auxin and cytokinin contents in the apical buds increased significantly at the germination initiation stage, and during the germination and vigorous growth phases, the auxin, cytokinin, and gibberellin contents increased. Polyacrylamide treatment activated α-amylase and promoted starch degradation, increasing soluble sugar content to provide nutrients and energy for sprouting. This study provides a promising approach for promoting potato tuber sprouting and seedling growth.

Introduction: Selenium-enriched foxtail millet (Setaria italica) represents a functional cereal with significant health benefits for humans. This study endeavors to examine the impact of foliar application of sodium selenite (Na₂SeO₄) on foxtail millet, specifically focusing on selenium (Se) accumulation and transportation within various plant tissues.Methods: To unravel the molecular mechanisms governing selenium accumulation and transportation in foxtail millet, we conducted a comprehensive analysis of selenium content and transcriptome responses in foxtail millet spikelets across different days (3, 5, 7, and 12) under Na₂SeO₄ treatment (200 μmol/L).Results: Foxtail millet subjected to selenium fertilizer exhibited significantly elevated selenium levels in each tissue compared to the untreated control. Selenate was observed to be transported and accumulated sequentially in the leaf, stem, and spikes. Transcriptome analysis unveiled a substantial upregulation in the transcription levels of genes associated with selenium metabolism and transport, including sulfate, phosphate, and nitrate transporters, ABC transporters, antioxidants, phytohormone signaling, and transcription factors. These genes demonstrated intricate interactions, both synergistic and antagonistic, forming a complex network that regulated selenate transport mechanisms. Gene co-expression network analysis highlighted three transcription factors in the tan module and three transporters in the turquoise module that significantly correlated with selenium accumulation and transportation. Expression of sulfate transporters (SiSULTR1.2b and SiSULTR3.1a), phosphate transporter (PHT1.3), nitrate transporter 1 (NRT1.1B), glutathione S-transferase genes (GSTs), and ABC transporter (ABCC13) increased with SeO₄^2- accumulation. Transcription factors MYB, WRKY, and bHLH were also identified as players in selenium accumulation.Conclusion: This study provides preliminary insights into the mechanisms of selenium accumulation and transportation in foxtail millet. The findings hold theoretical significance for the cultivation of selenium-enriched foxtail millet.