Molecular Characterization and Expression Profile of PaCOL1, a CONSTANS-like Gene in Phalaenopsis Orchid.

Yi-Ting Ke,Kung-Fu Lin,Chu-Han Gu,Ching-Hui Yeh

doi:10.3390/plants9010068

Abstract

CONSTANS (CO) and CONSTANS-like (COL) genes play important roles in coalescing signals from photoperiod and temperature pathways. However, the mechanism of CO and COLs involved in regulating the developmental stage transition and photoperiod/temperature senescing remains unclear. In this study, we identified a COL ortholog gene from the Taiwan native orchid Phalaenopsis aphrodite. The Phalaenopsis aphrodite CONSTANS-like 1 (PaCOL1) belongs to the B-box protein family and functions in the nucleus and cytosol. Expression profile analysis of Phalaenopsis aphrodite revealed that PaCOL1 was significantly expressed in leaves, but its accumulation was repressed during environmental temperature shifts. We found a differential profile for PaCOL1 accumulation, with peak accumulation at late afternoon and at the middle of the night. Arabidopsis with PaCOL1 overexpression showed earlier flowering under short-day (SD) conditions (8 h/23 °C light and 16 h/23 °C dark) but similar flowering time under long-day (LD) conditions (16 h/23 °C light and 8 h/23 °C dark). Transcriptome sequencing revealed several genes upregulated in PaCOL1-overexpressing Arabidopsis plants that were previously involved in flowering regulation of the photoperiod pathway. Yeast two-hybrid (Y2H) analysis and bimolecular fluorescence complementation (BiFC) analysis revealed that PaCOL1 could interact with a crucial clock-associated regulator, AtCCA1, and a flowering repressor, AtFLC. Furthermore, expressing PaCOL1 in cca1.lhy partially reversed the mutant flowering time under photoperiod treatment, which confirms the role of PaCOL1 function in the rhythmic associated factors for modulating flowering.

Highlights

Throughout their life span, plants are constantly exposed to changing environmental conditions.The sessile plants have to develop multitudinous strategies to survive the environmental challenges.The intimations of transition from vegetative to reproductive growth are determinant in the life cycle of plants
The genomic DNA of Phalaenopsis aphrodite CONSTANS-like 1 (PaCOL1) is 945 bp, which splices into a 744-bp sense RNA product
The genomic DNA of PaCOL1 is 945 bp, which splices into a 744-bp sense RNA product and and encodes a protein with 247 amino acids of 27.9 kDa (Figure S1B)

Summary

Introduction

Throughout their life span, plants are constantly exposed to changing environmental conditions.The sessile plants have to develop multitudinous strategies to survive the environmental challenges.The intimations of transition from vegetative to reproductive growth are determinant in the life cycle of plants. Throughout their life span, plants are constantly exposed to changing environmental conditions. The sessile plants have to develop multitudinous strategies to survive the environmental challenges. The intimations of transition from vegetative to reproductive growth are determinant in the life cycle of plants. To ensure the inception of flowering at the correct time, plants have to coalesce a diverse range of external and internal signals [1]. The photoperiod oscillator, ambient temperature, gibberellic acid, vernalization, and autonomous/aging pathways are the main factors involved in the transition of plants from the vegetative to reproductive stage [2,3,4,5]. The use of genetic approaches and functional analyses has identified several key moderators in the complex signal regulatory network in Arabidopsis thaliana; most of these moderators belong to the regulatory protein family [6,7]. Among the regulatory protein families, B-box (BBX) proteins are a group of transcription factors with one or more B-box domains that can be stabilized by binding to zinc

Methods

Results

Conclusion