Identification of miRNA Targets by AtFT Overexpression in Tobacco
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The onset of flowering is regulated by complex gene networks that integrate multiple genetic cues to floral transition in plants. The highly conserved florigen FLOWERING LOCUS T (FT) functions at the core of this process. Here, we demonstrate that overexpression of Arabidopsis FT in tobacco (oxAtFT) leads to precocious flowering in a photoperiod-independent manner. Strikingly altered phenotypes such as stunted growth, increased number of axillary branches, change in leaf morphology, and elongated style were observed in oxAtFT transgenic tobacco plants. In addition, the generation time of oxAtFT tobacco was drastically reduced by 8–10 weeks. We observed defects in lateral root formation in both oxAtFT tobacco and oxFT Arabidopsis lines. Interestingly, oxAtFT tobacco displayed significant heat and drought tolerance as compared to the wild type. Through small RNA profiling, we observed the upregulation of a conserved microRNA (nta-miR393a-5p) of miR393 family that targets the TRANSPORT INHIBITOR RESPONSE 1-like (TIR1) gene. Overall, the heterologous expression of AtFT in tobacco may have potential in imparting abiotic stress tolerance in other plant species through plant biotechnology–based approaches.
KeywordsFLOWERING LOCUS T Lateral root Stress tolerance Micro-RNA TIR1
We are grateful to Dr. Indu B. Maiti, Scientist, University of Lexington, Kentucky, USA, for kindly providing us with the AtFT codon-optimized clone. We thank Dr. Ajay Parida, Director, Institute of Life Sciences, Bhubaneswar, for his interest and suggestions in this study. We would also like to thank Mr. Arup Ghosh for helping in the DGE analysis and Mr. Abhimanyu Das for his technical assistance.
Ahamed Khan: conceptualization, performing experiments, analyzing data, and writing the manuscript. Ankita Shrestha: data curation, writing—original draft preparation. K C Panigrahi: data analysis and correction of the manuscript. Nrisingha Dey: data curation/analysis, manuscript finalization, and overall supervision.
Nt, Nicotiana tabacum; FT, FLOWERING LOCUS T; TIR1, TRANSPORT INHIBITOR RESPONSE 1-like; SOC1, SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1; AP1, APETLA 1; LA, Lateral root
This study was supported by the funds from Government of India under grant number BT/HRD/35/01/05/2015.
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