Search

The soil bioavailability of phosphorus (P) is often low because of its poor solubility, strong sorption and slow diffusion in most soils; however, stress due to excess soil P can occur in greenhouse production systems subjected to high levels of P fertilizer. Silicon (Si) is a beneficial element that can alleviate multiple biotic and abiotic stresses. Although numerous studies have investigated the effects of Si on P nutrition, a comprehensive review has not been published. Accordingly, here we review: (1) the Si uptake, transport and accumulation in various plant species; (2) the roles of phosphate transporters in P acquisition, mobilization, re-utilization and homeostasis; (3) the beneficial role of Si in improving P nutrition under P deficiency; and (4) the regulatory function of Si in decreasing P uptake under excess P. The results of the reviewed studies suggest the important role of Si in mediating P imbalance in plants. We also present a schematic model to explain underlying mechanisms responsible for the beneficial impact of Si on plant adaption to P-imbalance stress. Finally, we highlight the importance of future investigations aimed at revealing the role of Si in regulating P imbalance in plants, both at deeper molecular and broader field levels.

Previous studies have determined that lin-4, which was the first miRNA to be discovered, controls the timing of cell fate determination and life span in Caenorhabditis elegans. However, the mechanism of lin-4 involvement in these processes remains poorly understood. Fat storage is an essential aspect of the life cycle of organisms, and the function of lin-4 in fat accumulation is not clear. In this study, we showed that the fat content is reduced remarkably in C. elegans lin-4 mutants. Quantitative RT-PCR analysis revealed a considerable decrease in the levels of SBP-1 and OGA-1 mRNA in lin-4 mutants. We also showed that lin-4 mutants have a significantly shorter life span than wild-type worms. DCF assay experiments showed that the reactive oxygen species (ROS) levels increased and mitochondrial DNA (mtDNA) copy number decreased in loss-of-function lin-4 mutants. These mutants also showed attenuation of locomotion. Taken together, our findings suggest that lin-4 may play an important role in regulating fat accumulation and locomotion and that lin-4 may control the life span of C. elegans by mediating ROS production.