Role of miR156/SPL in rot architecture and nodulation in Medicago sativa (alfalfa)


Nasrollahi V., Kohalmi S., Hannoufa A. (2021) Role of miR156/SPL in rot architecture and nodulation in Medicago sativa (alfalfa). Webinar on Plant Science and Genomics 2021 (WPSG 2021), April 29-30, 2021


Background: The root system architecture in plants is critical because of its role in controlling nutrient cycling, water use efficiency and resistance to biotic and abiotic stresses. Similar to most other phenotypic traits, root system architecture is controlled at the molecular level by many genes, some of which were recently identified, including some coding for transcription factors from the SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE (SPL) family. We previously showed that transgenic alfalfa plants overexpressing microRNA156 (miR156) show increased nodulation, nitrogen fixation and longer roots. At least sixteen SPL genes, including SPL12 are targeted for silencing by microRNA156 in alfalfa. Thus, association of each target SPL gene to a trait or set of traits is essential for developing molecular markers for alfalfa breeding.
Objective: To determine the role of SPL12 gene in root architecture and nodulation by investigating the phenotypic changes associated with altered expression of SPL12 and by determining genes regulated by SPL12.
Methods: In this study, we used three alfalfa genotypes with silenced of enhanced expression of SPL12- silenced and overexpression alfalfa plants to investigate SPL12 function at the phenotypic and molecular levels. Furthermore, we conducted transcriptomics analysis of SPL12 -silencingRNAi alfalfa roots and identified differentially expressed genes.
Results: Phenotypic analysis showed that alfalfa plants with reduced SPL12 level had an increaseding in nodulation and root regeneration capacity. Illumina next-generation sequencing-based transcriptomics in root tissues of SPL12- silencinged genotypes also revealed SPL12 effects on genes involved in nodulation and nitrogen assimilation pathways.
Conclusion: The present findings suggest that the miR156/SPL12 gene regulatory module controlsregulates root development and nodulation, and is and they are also involved in nitrogen uptake and assimilation pathways in alfalfa.

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