MicroRNA profiling the resurrection plant Haberlea rhodopensis unveils essential regulators of survival under severe drought

Abstract

Small RNAs (sRNAs) are essential components of gene-regulatory networks, which guide plant development and tune it to environmental challenges. Though the past years have witnessed evidences on sRNA importance for stress response, there is scarce data on their involvement in resurrection plant survival under severe drought. Haberlea rhodopensis (hrh) is an angiosperm resurrection species, whose vegetative tissues can tolerate desiccation and recover upon rehydration. In this study, high-throughput sequencing sRNAs indicated a higher complexity of the sRNA population, especially of a 24 nt sRNA category, in the desiccated vegetative tissue of H. rhodopensis compared to unstressed tissues. The cross-species discovery was performed to predict 77 mature microRNAs (miRNAs), most of which were assigned to 23 high-confidence conserved miRNA families in the leaf tissue. Several members of the miR156/157, miR166, and miR399 families were found to be desiccation-responsive. The miR156/157 family members were found up-regulated upon dehydration and down-regulated upon rehydration, while the miR166 and miR399 family members followed an opposite trend of expression. A probable miR156/157 target, orthologous to the SQUAMOSA promoter binding proteinlike, was reconstructed in H. rhodopensis based on genomic data available for this species and the closely related Boea hygrometrica. Reverse transcription quantittative PCR analysis confirmed the expression profile of hrh-miR156a-5p and hrh-miR157-5p established by sRNA sequencing and revealed an inverse expression pattern between these miRNAs and their targets in the desiccated tissue. Our study suggests that the miR156/157 and miR399 families are essential for plant survival under severe drought due to their ability to control plant development and growth by modulating transcription factor expression.

Two Decades of Desiccation Biology: A Systematic Review of the Best Studied Angiosperm Resurrection Plants

“…The advances in "omics" techniques enable exploration of new genes, transcripts, metabolites, proteins, and microbes that contribute to desiccation tolerance. Recently, genomic and transcriptomic analyses of B. hygrometrica, C. plantagineum, E. nindensis, H. rhodopensis, L. brevidens, O. thomaeum, T. loliiformis, and X. schlechteri, have identified gene families and transcripts involved in desiccation responses [14][15][16][17][18][19][20][21]. Metabolomic analysis of C. plantagineum, L. brevidens, M. flabellifolia, and X. schlechteri have provided insight into the central role of sugars (sucrose in particular), selected amino and organic acids, and phenolic antioxidants [22][23][24].…”

PlantMirP2: An Accurate, Fast and Easy-To-Use Program for Plant Pre-miRNA and miRNA Prediction

“…The miR396-GRF/GIF system can effectively regulate plant growth, and is a promising target for increasing plant yield [4]. Under drought conditions, the miR156/157 and miR399 families can regulate the expression of transcription factor to enhance the viability of plants [5].…”