Involvement of the miR156/SPL module in flooding response in Medicago sativa

Citation

Feyissa, B.A., Amyot, L., Nasrollahi, V., Papadopoulos, Y., Kohalmi, S.E., Hannoufa, A. (2021). Involvement of the miR156/SPL module in flooding response in Medicago sativa. Scientific Reports, [online] 11(1), http://dx.doi.org/10.1038/s41598-021-82450-7

Plain language summary

Background: Our previous research revealed a role for the small plant microRNA, miR156, in affecting plant development, metabolite composition, and response to abiotic stress. Here we investigated the involvement and possible mechanism of action of the miR156/SPL module in flooding tolerance in this plant. For that, we used miR156 overexpressing, SPL13RNAi, flood-tolerant (AAC-Trueman) and -sensitive (AC-Caribou) alfalfa cultivars exposed to flooding.

Results: Physiological analysis, hormone profiling and global transcriptome changes revealed
a role for miR156/SPL module in flooding tolerance. We also identified nine novel alfalfa SPLs (SPL1,
SPL1a, SPL2a, SPL7, SPL7a, SPL8, SPL13a, SPL14, SPL16) responsive to flooding. Our results also
showed a possible ABA-dependent SnRK1 upregulation to enhance miR156 expression, resulting in
downregulation of SPL4, SPL7a, SPL8, SPL9, SPL13, and SPL13a.

Conclusion: We conclude that the miR156/SPL gene regulatory network exerts effects that induce flooding adaptive responses in alfalfa and modulate stress physiology by affecting the transcriptome, ABA metabolites and secondary metabolism.

Abstract

The highly conserved plant microRNA, miR156, affects plant development, metabolite composition, and stress response. Our previous research revealed the role of miR156 in abiotic stress response in Medicago sativa exerted by downregulating SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE transcription factors. Here we investigated the involvement and possible mechanism of action of the miR156/SPL module in flooding tolerance in alfalfa. For that, we used miR156 overexpressing, SPL13RNAi, flood-tolerant (AAC-Trueman) and -sensitive (AC-Caribou) alfalfa cultivars exposed to flooding. We also used Arabidopsis ABA insensitive (abi1-2, abi5-8) mutants and transgenic lines with either overexpressed (KIN10-OX1, KIN10-OX2) or silenced (KIN10RNAi-1, KIN10RNAi-2) catalytic subunit of SnRK1 to investigate a possible role of ABA and SnRK1 in regulating miR156 expression under flooding. Physiological analysis, hormone profiling and global transcriptome changes revealed a role for miR156/SPL module in flooding tolerance. We also identified nine novel alfalfa SPLs (SPL1, SPL1a, SPL2a, SPL7, SPL7a, SPL8, SPL13a, SPL14, SPL16) responsive to flooding. Our results also showed a possible ABA-dependent SnRK1 upregulation to enhance miR156 expression, resulting in downregulation of SPL4, SPL7a, SPL8, SPL9, SPL13, and SPL13a. We conclude that these effects induce flooding adaptive responses in alfalfa and modulate stress physiology by affecting the transcriptome, ABA metabolites and secondary metabolism.

Publication date

2021-12-01