Abstract
The developmental functions of miR156-SPL regulatory network have been extensively studied in Arabidopsis, but the downstream genes regulated by each SPL have not been well characterized. In this study, Next Generation Sequencing-based transcriptome analysis was performed on roots of wild type (WT) and miR156 overexpression (miR156OE) plants. One of the SPL genes, SPL10, which represses lateral root growth in Arabidopsis, was significantly downregulated in miR156OE plants. A transcription factor, AGAMOUS-like MADS box protein 79 (AGL79), was also significantly downregulated in the miR156OE plants, but was upregulated in the SPL10 overexpression (SPL10OE) Arabidopsis plants. In addition, SPL10 was found to bind to the core consensus SPL binding sequences in AGL79 gene. Moreover, analyses of complementation lines revealed a linear relationship between SPL10 and AGL79 in regulating Arabidopsis plant development. In addition, it was observed that plant phenotypes are AGL79 dose-dependent, with higher expression causing narrow leaf shape, less number of leaves and early flowering time, whereas relatively lower AGL79 overexpression produce plants with more rosette leaves and more lateral branches. Our findings revealed direct binding of SPL10 to AGL79 promoter, which further suggests a role for miR156/SPL10 module in plant lateral root growth by directly regulating AGL79.
Highlights
MicroRNAs are a class of non-coding RNAs with a length of 19–24 nucleotides that control gene expression at the posttranscriptional level (Bartel, 2004; Cuperus et al, 2011; Nozawa et al, 2012)
SPL10 was reported earlier to play a dominant role in repressing lateral root development (Yu et al, 2015), so we investigated the root phenotypes in wild type (WT), pSPL10-SPL10-GFP (SPL10 overexpression under native promoter), miR156OE and MIM156 plants
These results showed that the expression level of SPL10 is negatively correlated to root development in Arabidopsis
Summary
MicroRNAs (miRNAs) are a class of non-coding RNAs with a length of 19–24 nucleotides that control gene expression at the posttranscriptional level (Bartel, 2004; Cuperus et al, 2011; Nozawa et al, 2012). Of all the miRNAs, miR156 is one of the most conserved in plants, where it regulates transition from the juvenile to the adult phase of vegetative development (Wu and Poethig, 2006; Chuck et al, 2007). A genetic function study of each individual SPL gene in vegetative and reproductive phase development was reported (Xu et al, 2016) Based on this functional analysis, miR156-regulated SPL genes could be divided into three groups: (1) SPL2, SPL9, SPL10, SPL11, SPL13, and SPL15 play crucial roles in both juvenile-to-adult vegetative transition and vegetative-to-reproductive transition. Based on this functional analysis, miR156-regulated SPL genes could be divided into three groups: (1) SPL2, SPL9, SPL10, SPL11, SPL13, and SPL15 play crucial roles in both juvenile-to-adult vegetative transition and vegetative-to-reproductive transition. (2) SPL3, SPL4, and SPL5 are involved in promoting the floral meristem identify transition. (3) SPL6 is predicted to participate in regulating some physiological processes, but its exact function is still not fully understood (Xu et al, 2016)
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