MicroRNA transcriptome variations in the multi-tepal mutant provide insights into the floral patterning of the orchid Cymbidium goeringii

Cymbidium goeringii is a very famous traditional orchid plant in China.
In particular, the multi-tepal mutants have considerable ecological and cultural value.
However, the current understanding of molecular mechanisms of floral patterning and multi-tepal development is still limited.
In this study, we performed small RNA profiling of the wild-type and typical multi-tepal mutant for the first time, to identify miRNAs regulating floral morphogenesis of C. goeringii.
Small RNA sequencing revealed 132 conserved miRNA families expressed in C. goeringii flower, corresponding to 6,459 putative targets.
From the computational analysis of miRNA expression levels based on deep sequencing data, we found 11 miRNA families, which included well-known floral-related miR156, miR166/165, miR167, miR319, and miR396, were differentially expressed between the wild-type and the mutant, corresponding to 455 putative targets including a great number of floral related and plant hormone-responsive genes.
Using stem-loop and real-time RT-PCR, we confirmed miR396-GRF (growth-regulating factor), miR319-TCP (TEOSINTE BRANCHED1/CYCLOIDEA/PC transcription factors), and miR167-ARF (Auxin Response Factor) regulatory cascades played important roles in the regulation of multi-tepal development.
Our results shed light on the regulatory mechanism of multi-tepal development of C. goeringii, and provide a base for future genome-wide orchid biology and biotechnology research.

II Asian Horticultural Congress

Fengxi Yang, Genfa Zhu

Cymbidium goeringii, multi-tepal mutant, small RNA profling, microRNA

https://doi.org/10.17660/ActaHortic.2018.1208.12