Yan Qin

Selenium (Se) biofortification in rice addresses dietary Se deficiencies. While Se fertilization is key, the efficiency and molecular mechanisms differ amo

Root rot disease severely threatens tropical fruit production, leading to plant mortality and reduced yields; however, the mechanisms of host defense responses and pathogen infection remain poorly understood. In this study, Fusarium acutatum was isolated from diseased Annona squamosa roots and identified through morphological features and ITS phylogeny (99.8% identity). Infection triggered a marked activation of antioxidant defenses, with elevated POD, SOD, PAL, PPO, and CAT activities. Transcriptomic and TMT-based quantitative proteomic analyses identified 23,791 and 74,403 differentially expressed genes (DEGs) and 367 and 609 differentially expressed proteins (DEPs) in root at 5 and 10 days post inoculation, respectively, relative to the control. These DEGs and DEPs were consistently enriched in pathways involving redox regulation, protein synthesis and processing, ubiquitin-mediated proteolysis, phenylpropanoid and flavonoid metabolism, cell wall remodeling, plant–pathogen interaction and MAPK signaling. Integrated transcriptomic–proteomic correlation analysis showed clear positive associations between key defense-related genes and proteins, suggesting that phenylpropanoid metabolism and reactive oxygen species (ROS) scavenging play central roles in resistance. Key genes such as CHI2, CHS, and CYP were strongly induced and validated by qPCR, supporting coordinated activation of the defense systems. Furthermore, F. acutatum exhibited upregulation of 50 pathogenic-related proteins, including 4 cell wall-degrading enzymes (e.g., CBH1, pectate lyase), 5 metabolic regulation or signal transduction enzymes (e.g., gabD, TPI, and ENO) and 3 potential effectors, suggesting coordinated pathogen strategies for host colonization. Collectively, this study provides comprehensive multi-omics insight into the molecular mechanisms underlying A. squamosa defense against F. acutatum and offers candidate targets supported by omics evidence, serving as a theoretical reference for the management of root rot.

Cadmium (Cd) is one of the heavy metals that contaminate rice cultivation, and reducing Cd contamination in rice through agronomic measures is a hot research topic. In this study, foliar sprays of gibberellins (GA) and brassinolide (BR) were applied to rice under Cd stress in hydroponic and pot experiments. After foliar spraying of GR and BR, the biomass of rice plants grown in either hydroponics or soil culture was significantly higher or even exceeded that in the absence of Cd stress. In addition, photosynthetic parameters (maximum fluorescence values), root length and root surface area, and CAT, SOD and POD activities were significantly improved. The MDA content decreased in the shoots, suggesting that the application of GR and BA may have enhanced photosynthesis and antioxidant function to alleviate Cd stress. Furthermore, the BR and GA treatments decreased the Cd content of rice roots, shoots and grains as well as the Cd transfer coefficient. Cd chemical morphology analysis of rice roots and shoots showed that the proportion of soluble Cd (Ethanol-Cd and Water-Cd) decreased, whereas the proportion of NaCl-Cd increased. Analysis of the subcellular distribution of Cd in rice roots and above ground showed that the proportion of Cd in the cell wall increased after foliar spraying of GA and BR. The results indicate that after foliar application of GA and BR, more of the Cd in rice was transformed into immobile forms and was fixed in the cell wall, thus reducing the amount in the seeds. In summary, foliar sprays of GA and BR can reduce the toxic effects of Cd on rice plants and reduce the Cd content in rice grains, with GA being more effective.