Carbon nanoparticles influence photomorphogenesis and flowering time in Arabidopsis thaliana

Abstract

Inclusion of carbon nanoparticles in growth medium accelerates timing to flower by down-regulating phytochrome B in a CONSTANS-independent but photoperiod-dependent manner in Arabidopsis thaliana. Despite the recognized importance of nanoparticles in plant development over the last decade, the effect of carbon nanoparticles (CNPs) on plant processes such as photomorphogenesis and flowering time control is poorly understood. We explored the uptake, accumulation and effect of CNPs on seedling development and flowering time control in Arabidopsis thaliana (At). CNPs uptake was demonstrated using Raman spectroscopy and light microscopy that affected At seedling growth and flowering time in a dose-dependent manner. The highest accumulation of CNPs was observed in leaves followed by stem and root tissues. CNPs treatment enhanced seed germination, showed elongated hypocotyl, larger cotyledon area and increased chlorophyll content in At seedlings. CNPs treatment induced early flowering in both long-day and short-day growth conditions indicating a photoperiod-dependent effect. CNPs-treated seedlings showed a drastic reduction in the relative abundance of phytochrome B (PHYB) transcript. Further, we analyzed the transcript abundance of at least one major component involved in various pathways that regulate flowering such as (1) photoperiod, (2) gibberellic acid (GA), (3) vernalization and (4) autonomous. An up-regulation of transcript levels of PHYTOCHROME INTERACTING FACTOR 4 (PIF4), GIGANTEA (GI), REPRESSOR OF GIBBERELLIC ACID 1 (RGA1) and LEAFY (LFY) were observed, however, there were no changes in the transcript levels of CONSTANS (CO), VERNALIZATION 1 (VRN1) and FLOWERING CONTROL LOCUS A (FCA). Despite the up-regulation of RGA1, we conclude that the earlier flowering is most likely GA-independent. Here, we demonstrated that the early flowering in CNPs-treated seedlings was PHYB and photoperiod-dependent.

The Photoperiodic Flowering Time Regulator FKF1 Negatively Regulates Cellulose Biosynthesis

“…their ability to adjust starch synthesis in response to variations in day length (Mugford et al, 2014), which suggests an active metabolic role of FKF1 in determining the flowering time. Several flowering-related genes that respond to day length variation were also found to respond to carbon/carbon nanoparticles (Ohto et al, 2001;Kumar et al, 2018), which implies that these genes are responding to internal carbon status in determining the flowering time. Based on the fact that cellulose biosynthesis is a known carbon-dependent process (Ivakov et al, 2017), we speculate that the flowering time and carbon metabolic status are coordinated for effective transition from vegetative to reproductive transition, in which FKF1 appears to be playing a key role, and that these pathways are diverging downstream of FKF1.…”

Shade tolerance in Swarnaprabha rice is associated with higher rate of panicle emergence and positively regulated by genes of ethylene and cytokinin pathway

“…Gene-specific primers used for qRT-PCR are listed in Supplementary Table 3. The PCR recipe and the thermocycler program used were similar to as done previously 51 . For normalization ACTIN was used as control.…”

Multi-Walled Carbon Nanotubes can Promote Root Hair Development Through Nitric Oxide and Ethylene Pathways

“…Previous research on the relationship between CNTs and plants mainly focused on seed germination [8][9][10], primary root growth [11][12][13], lateral root development [14][15][16], owering [17,18], and stress tolerance [19,20]. However, except the studies of Joshi et al [21] and García-Sánchez et al [22], few investigations has been nished on the functions of multi-walled carbon nanotube (MWCNTs; one of kinds of CNTs) on root hairs and corresponding mechanism, and their phenotypes were controversial.…”