An Optimized Transformation System and Functional Test of CYC-Like TCP Gene CpCYC in Chirita pumila (Gesneriaceae).

Jing Liu,Qi Liu,Xia Yang,Yang Wang,Jie Wu,Yin-Zheng Wang,Juan-Juan Wang,Fang-Pu Liu

doi:10.3390/ijms22094544

Abstract

The development of an ideal model plant located at a key phylogenetic node is critically important to advance functional and regulatory studies of key regulatory genes in the evolutionary developmental (evo-devo) biology field. In this study, we selected Chirita pumila in the family Gesneriaceae, a basal group in Lamiales, as a model plant to optimize its genetic transformation system established previously by us through investigating a series of factors and further conduct functional test of the CYC-like floral symmetry gene CpCYC. By transforming a RNAi:CpCYC vector, we successfully achieved the desired phenotypes of upright actinomorphic flowers, which suggest that CpCYC actually determines the establishment of floral zygomorphy and the horizontal orientation of flowers in C. pumila. We also confirmed the activities of CpCYC promoter in dorsal petals, dorsal/lateral staminodes, as well as the pedicel by transferring a CpCYC promoter:GUS vector into C. pumila. Furthermore, we testified the availability of a transient gene expression system using C. pumila mesophyll protoplasts. The improved transformation system together with the inherent biological features would make C. pumila an attractive new model in functional and regulatory studies for a broad range of evo-devo issues.

Highlights

There are an estimated 352,000 species of flowering plants or angiosperms, much more than all other land plants that count no more than 35,000 species [1]
On seeds on different germination media (SGM)-IV (1/2 MS medium supplemented with 1% sucrose), radicle began to elongate after five-days of sowing, and green cotyledons could be clearly observed with naked eyes on the seventh day
We systematically optimized the conditions for seed germination, tissue culture and genetic transformation in C. pumila

Summary

Introduction

There are an estimated 352,000 species of flowering plants or angiosperms, much more than all other land plants that count no more than 35,000 species [1]. The organ types determined by organ identity genes functioning in frame of the ABC model are the basis of final floral form. According to the classical ABC model, the identities of sepals, petals, stamens, and carpels within a flower are, respectively, specified by A-function, A- and B-functions, B- and C-functions, and C-function [4,5]. The debates about the A-function defined in the classical ABC model have become conspicuous [3,6]. It is urgent to conduct systematic comparative analyses of A-function genes in more species with key phylogenetic position outside the classical model plants [3,6,7]

Methods

Results

Discussion

Conclusion