Yang, Shu-Yi, Lu, Wen-Chien, Ko, Swee-Suak, Sun, Ching-Mei, Hung, Jo-Chi and Chiou, Tzyy-Jen* (2020) uORF and Phosphate-Regulated Expression of Rice OsNLA1 Controls Phosphate Transport and Reproduction. Plant Physiology: pp.01101.02019
Rice (Oryza sativa) OsNLA1 has been proposed to play a crucial role in regulating phosphate (Pi) acquisition in roots, similar to that of Arabidopsis AtNLA. However, unlike AtNLA, OsNLA1 is not a target of miR827, a Pi starvation-induced miRNA. It is, therefore, of interest to know whether the expression of OsNLA1 depends on Pi supply and how it is regulated. In this study, we provide evidence that OsNLA1 controls Pi acquisition by directing the degradation of several OsPHT1 Pi transporters (i.e., OsPT1/2/4/7/8/12). We further show that OsNLA1 has an additional function in reproduction and uncover the mechanism of its expression regulation. Analysis of mRNA levels, promoter-GUS (β-glucuronidase) activity and protoplast transient expression showed that the expression of OsNLA1.1, the most abundant transcript variant, is upregulated in response to increasing Pi supply. The OsNLA1 promoter region was found to contain an upstream open reading frame (uORF) that is required for Pi-responsive expression regulation. OsNLA1 promoter activity was observed in roots, ligules, leaves, sheaths, pollen grains, and surrounding the vascular tissues of anthers, suggesting that OsNLA1 is important throughout the development of rice. Disruption of OsNLA1 resulted in increased Pi uptake from roots as well as impaired pollen development and reduced grain production. In summary, our study reveals that Pi-induced OsNLA1 expression regulated by a unique mechanism functions in Pi acquisition, Pi translocation, and reproductive success.
OsNLA1 is expressed in reproductive organs and required for pollen viability and grain production.
Promoter activity of OsNLA1 in panicle (A, Bar = 2 mm), spikelet (B, Bar = 1 mm) and cross section of anther (C, Bar = 50 μm). Panicles of the WT and osnla mutants at grain maturity stage (D, Bar = 2 cm). Spikelets of the WT and osnla mutants at one day before anthesis (E, Bar = 1 mm). Pollen viability assay determined by starch staining (F). The percentage of each category was quantitated as shown in the bar chart (G). Standard errors refer to 4 biological replicates. Asterisks indicate a statistically significant difference from WT. ***, P < 0.01; *, P < 0.1.
2020/04/13 11:00 AM
Dr. Julian Schroeder (Novartis Distinguished Professor in Plant Sciences, University of California, San Diego, USA)
CO2 Sensing in Plants and New Insights into Drought-Induced Abscisic Acid Signal Transduction
Auditorium A134, Agricultural Technology Building 2020/09/07 10:00 AM
Dr. Michael Alan Huffman (Associate Professor (tenured), Department of Ecology and Social Behavior, Primate Research Institute, Kyoto University, Japan)
Learn from primate self-medication about the maintenance of human and domestic animal health?
Auditorium A134, Agricultural Technology Building