Molecular Manipulation of the miR396 and miR399 Expression Modules Alters the Response of Arabidopsis thaliana to Phosphate Stress

Joseph L Pegler; Duc Quan Nguyen; Jackson M J Oultram; Christopher P L Grof; Andrew L Eamens

doi:10.3390/plants10122570

Molecular Manipulation of the miR396 and miR399 Expression Modules Alters the Response of Arabidopsis thaliana to Phosphate Stress

Plants (Basel). 2021 Nov 24;10(12):2570. doi: 10.3390/plants10122570.

Authors

Joseph L Pegler¹, Duc Quan Nguyen^{1

2}, Jackson M J Oultram¹, Christopher P L Grof¹, Andrew L Eamens^{1

3

4}

Affiliations

¹ Centre for Plant Science, School of Environmental and Life Sciences, Faculty of Science, University of Newcastle, Callaghan, NSW 2308, Australia.
² Institute of Genome Research, Vietnam Academy of Research and Technology, 18 Hoang Quoc Viet Str., Cau Giay, Hanoi 100000, Vietnam.
³ School of Science, Technology and Engineering, University of the Sunshine Coast, Maroochydore, QLD 4558, Australia.
⁴ School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia.

Abstract

In plant cells, the molecular and metabolic processes of nucleic acid synthesis, phospholipid production, coenzyme activation and the generation of the vast amount of chemical energy required to drive these processes relies on an adequate supply of the essential macronutrient, phosphorous (P). The requirement of an appropriate level of P in plant cells is evidenced by the intricately linked molecular mechanisms of P sensing, signaling and transport. One such mechanism is the posttranscriptional regulation of the P response pathway by the highly conserved plant microRNA (miRNA), miR399. In addition to miR399, numerous other plant miRNAs are also required to respond to environmental stress, including miR396. Here, we exposed Arabidopsis thaliana (Arabidopsis) transformant lines which harbor molecular modifications to the miR396 and miR399 expression modules to phosphate (PO₄) starvation. We show that molecular alteration of either miR396 or miR399 abundance afforded the Arabidopsis transformant lines different degrees of tolerance to PO₄ starvation. Furthermore, RT-qPCR assessment of PO₄-starved miR396 and miR399 transformants revealed that the tolerance displayed by these plant lines to this form of abiotic stress most likely stemmed from the altered expression of the target genes of these two miRNAs. Therefore, this study forms an early step towards the future development of molecularly modified plant lines which possess a degree of tolerance to growth in a PO₄ deficient environment.

Keywords: Arabidopsis thaliana (Arabidopsis); RT-qPCR gene expression analysis; miR399; microRNA396 (miR396); molecular manipulation; phosphate (PO4) starvation; phosphorous (P).