Light is a major environmental factor that affects metabolic pathways and stimulates the production of secondary metabolites in potato. However, adaptive changes in potato metabolic pathways and physiological functions triggered by light are partly explained by gene expression changes. Regulation of secondary metabolic pathways in potato has been extensively studied at transcriptional level, but little is known about the mechanisms of post-transcriptional regulation by miRNAs. Therefore, to identify light-responsive miRNAs/mRNAs and construct putative metabolism pathways regulated by the miRNA–mRNA pairs, researchers from Gansu Agricultural University performed an integrated omics (sRNAome and transcriptome) analysis on potato under light stimulus.

In their study, a total of 31 and 48 miRNAs were identified to be differentially expressed in the leaves and tubers, respectively. Among the DEGs, 1353 genes in the leaves and 1841 genes in the tubers were upregulated, while 1595 genes in the leaves and 897 genes in the tubers were downregulated by light. Mapman enrichment analyses showed that genes related to MVA pathway, alkaloids-like, phenylpropanoids, flavonoids, and carotenoids metabolism were significantly upregulated, while genes associated with major CHO metabolism were repressed in the leaves and tubers. Integrated miRNA and mRNA profiles revealed that light-responsive miRNAs were important regulators in alkaloids metabolism, UMP salvage, lipid biosynthesis, and cellulose catabolism. Moreover, several miRNAs may participate in glycoalkaloids metabolism via JA signaling pathway, UDP-glucose biosynthesis and hydroxylation reaction.

 

ct

Numbers of CT-specific reads, RT-specific reads, and common reads between CT and RT libraries. Venn diagrams represent genome-matched total clean reads (a) and unique reads (b) between control library (CT) and light-treated (RT) in the tuber

This study provides a global view of miRNA and mRNA expression profiles in potato response to light. These results suggest that miRNAs might play important roles in secondary metabolic pathways, especially in glycoalkaloid biosynthesis. The findings improve our understanding of the genetic regulation of secondary metabolite pathways and pave the way for future application of genetically engineered potato.

Reference
Y. Qiao, J. Zhang, J. Zhang, et al. (2016) Integrated RNA-seq and sRNA-seq analysis reveals miRNA effects on secondary metabolism in Solanum tuberosum L Mol Genet Genomics doi:10.1007/s00438-016-1253-5 [article]

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