Overexpression of PvCO1, a bamboo CONSTANS-LIKE gene, delays flowering by reducing expression of the FT gene in transgenic Arabidopsis

Abstract

BackgroundIn Arabidopsis, a long day flowering plant, CONSTANS (CO) acts as a transcriptional activator of flowering under long day (LD) condition. In rice, a short day flowering plant, Hd1, the ortholog of CO, plays dual functions in respond to day-length, activates flowering in short days and represses flowering in long days. In addition, alleles of Hd1 account for ~ 44% of the variation in flowering time observed in cultivated rice and sorghum. How does it work in bamboo? The function of CO in bamboo is similar to that in Arabidopsis?ResultsTwo CO homologous genes, PvCO1 and PvCO2, in Phyllostachys violascens were identified. Alignment analysis showed that the two PvCOLs had the highest sequence similarity to rice Hd1. Both PvCO1 and PvCO2 expressed in specific tissues, mainly in leaf. The PvCO1 gene had low expression before flowering, high expression during the flowering stage, and then declined to low expression again after flowering. In contrast, expression of PvCO2 was low during the flowering stage, but rapidly increased to a high level after flowering. The mRNA levels of both PvCOs exhibited a diurnal rhythm. Both PvCO1 and PvCO2 proteins were localized in nucleus of cells. PvCO1 could interact with PvGF14c protein which belonged to 14–3-3 gene family through B-box domain. Overexpression of PvCO1 in Arabidopsis significantly caused late flowering by reducing the expression of AtFT, whereas, transgenic plants overexpressing PvCO2 showed a similar flowering time with WT under LD conditions. Taken together, these results suggested that PvCO1 was involved in the flowering regulation, and PvCO2 may either not have a role in regulating flowering or act redundantly with other flowering regulators in Arabidopsis. Our data also indicated regulatory divergence between PvCOLs in Ph. violascens and CO in Arabidopsis as well as Hd1 in Oryza sativa. Our results will provide useful information for elucidating the regulatory mechanism of COLs involved in the flowering.ConclusionsUnlike to the CO gene in Arabidopsis, PvCO1 was a negative regulator of flowering in transgenic Arabidopsis under LD condition. It was likely that long period of vegetative growth of this bamboo species was related with the regulation of PvCO1.Electronic supplementary materialThe online version of this article (10.1186/s12870-018-1469-0) contains supplementary material, which is available to authorized users.

ThCOL2 Improves the Salt Stress Tolerance of Tamarix hispida

“…In recent years, COL transcription factors have been identified in many plants, such as Arabidopsis thaliana (Zhang et al, 2014), Brassica juncea (Muntha et al, 2019), Phyllostachys violascens (Xiao et al, 2018), and Oryza sativa (Sheng et al, 2016). Most COL transcription factors have been reported to be involved in flowering regulation.…”

Organelle Visualization With Multicolored Fluorescent Markers in Bamboo

“…It should be noted that studies for bamboo protein subcellular localization and protein-protein interaction have been reported only in heterologous expression. Usually, bamboo proteins are fluorescence tagged and expressed in rice protoplasts, onion epidermal cells, or tobacco leaves (Ge et al, 2017;Liu et al, 2018;Xiao et al, 2018). However, different expression patterns may arise from heterologous systems (Marion et al, 2008), and we have also found that several fluorescence-tagged proteins were functional in the Arabidopsis transient expression system but were not expressed or did not show similar subcellular distribution in moso bamboo protoplasts.…”

“…Over the past decade, a set of organelle markers containing multicolored fluorescent tags have been developed in Arabidopsis and rice and used for co-localization studies with transient expression method (Nelson et al, 2007). Up to now, the subcellular localization of bamboo proteins has been mostly studied in heterologous plants such as Arabidopsis and rice leaf protoplasts (Ge et al, 2017;Zhang et al, 2018), onion epidermal cells (Xiao et al, 2018), or tobacco leaves (Liu et al, 2018). However, ectopic expression of proteins in different plant species may result in mis-localization because of the non-conservation of signal sequences or posttranscriptional modifications in the heterologous expression system (Marion et al, 2008).…”

Mapping Covariation Quantitative Trait Loci That Control Organ Growth and Whole-Plant Biomass

“…CRA1 was expressed during flowering, petal differentiation, and expansion (Li et al, 2008; Sekhon et al, 2012), and in collective leaf structure, flower, petal, pollen, and sepal (Shapiguzov et al, 2016; Robinson et al, 2018). HIPP25 was expressed in LP.04 at the four-leaves-visible stage and in LP.06 at the six-leaves-visible, flowering, petal differentiation, and petal expansion stages (Jiang et al, 2012; Ogawa et al, 2015; Xiao et al, 2018) and in the carpel, leaf apex, petal, plant embryo, pollen, root, sepal, stamen, stem, and leaf vasculature (Chauvin et al, 2013; Shapiguzov et al, 2016; Luo et al, 2018). These two cov QTLs are major contributors to leaf growth and biomass accumulation in Arabidopsis .…”