Effects of the repression of GIGANTEA gene StGI.04 on the potato leaf transcriptome and the anthocyanin content of tuber skin

Evolution of light-dependent functions of GIGANTEA

GIGANTEA (GI) is a multifaceted plant-specific protein that originated in a streptophyte ancestor. The current known functions of GI include circadian clock control, light signalling, flowering time regulation, stomata response, chloroplast biogenesis, accumulation of anthocyanin, chlorophyll, and starch, phytohormone signalling, senescence, and response to drought, salt, and oxidative stress. Six decades since its discovery, no functional domains have been defined, and its mechanism of action is still not well characterized. In this review, we explore the functional evolution of GI to distinguish between ancestral and more recently acquired roles. GI integrated itself into various existing signalling pathways of the circadian clock, blue light, photoperiod, and osmotic and oxidative stress response. It also evolved parallelly to acquire new functions for chloroplast accumulation, red light signalling, and anthocyanin production. In this review, we have encapsulated the known mechanisms of various biological functions of GI, and cast light on the evolution of GI in the plant lineage.

Preliminary establishment of genetic transformation system for embryogenic callus of Acer truncatum 'Lihong'

Introduction

Acer truncatum Bunge, belonging to the Acer genus in the Aceraceae family, is a commonly planted afforestation species across China, Japan, Korea, Europe, and North America. Renowned for its vibrant fall colors, it holds significant ecological and ornamental value.

Methods

In this study, Acer truncatum ' Lihong ' was used as the research object. Starting from the callus induction of explants, the embryogenic callus of Acer truncatum 'Lihong' was obtained by systematically optimizing the medium and culture conditions. Then, the candidate gene AtrGST894 screened by transcriptome sequencing was transformed into embryogenic callus by Agrobacterium-mediated transformation. The genetic transformation system of Acer truncatum 'Lihong' embryogenic callus was initially established by continuously adjusting the conditions of Agrobacterium tumefaciens infection receptor materials, thus laying a material foundation for the study of the molecular regulation mechanism of Acer truncatum 'Lihong' leaf color, and also preparing for the later molecular improvement breeding of Acer truncatum. Therefore, this study has important theoretical and practical significance.

Results

The results showed that the best medium for callus induction of Acer truncatum was 1/2MS+2 mg/L 2,4-D+0.3 mg/L 6-BA+0.5 mg/L NAA; The embryogenic callus induction medium of Acer truncatum was 1/2MS+3.0mg/L 6-BA+2.0mg/L TDZ+0.5mg/L IBA+0.1mg/L GA3; The proliferation medium of embryogenic callus of Acer truncatum was WPM+1.0mg/L TDZ+0.5mg/L IBA+0.1mg/L GA3+3mg/L 6-BA+1.0mg/L KT; The infection experiment of Agrobacterium tumefaciens on the embryogenic callus of Acer truncatum showed that the best antibacterial medium was WPM+30g/L sucrose+8g/L agar+0.5g/L acid-hydrolyzed casein+0.2mg/L KT+1.0 mg/L TDZ+0.5 mg/L IBA+0.1 mg/L GA3+200mmol/L carboxybenzyl+200mg/L cephalosporin, and then WPM+30g/L sucrose+8g/L agar+0.5g/L acid-hydrolyzed casein+0.2mg/L KT+1.0 mg/L TDZ+0.5 mg/L IBA+0.1 mg/L GA3+300mmol/L carboxybenzyl+200mg/L cephalosporin+25mg/L hygromycin. Screening medium screening, The obtained embryogenic callus browning rate, pollution rate and mortality rate were the lowest, and maintained vigorous growth.

Discussion

The embryogenic callus was used as the infection material to verify that we successfully transferred the target gene into the embryogenic callus, which means that the genetic transformation system of Acer truncatum embryogenic callus was partially completed, and the infection process could be effectively inhibited. Although there was partial browning, it could continue to proliferate. Therefore, in future experiments, the focus is still to continue to verify the optimal conditions for optimizing the genetic transformation of Acer truncatum embryogenic callus and to solve the problems of difficulty in embryonic callus germination.

PpGATA21 Enhances the Expression of PpGA2ox7 to Regulate the Mechanism of Cerasus humilis Rootstock-Mediated Dwarf in Peach Trees

Dwarfing rootstocks enhance planting density, lower tree height, and reduce both labor in peach production. Cerasus humilis is distinguished by its dwarf stature, rapid growth, and robust fruiting capabilities, presenting substantial potential for further development. In this study, Ruipan 4 was used as the scion and grafted onto Amygdalus persica and Cerasus humilis, respectively. The results indicate that compared to grafting combination R/M (Ruipan 4/Amygdalus persica), grafting combination R/O (Ruipan 4/Cerasus humilis) plants show a significant reduction in height and a significant increase in flower buds. RNA-seq indicates that genes related to gibberellin (GA) and auxin metabolism are involved in the dwarfing process of scions mediated by C. humilis. The expression levels of the GA metabolism-related gene PpGA2ox7 significantly increased in R/O and are strongly correlated with plant height, branch length, and internode length. Furthermore, GA levels were significantly reduced in R/O. The transcription factor PpGATA21 was identified through yeast one-hybrid screening of the PpGA2ox7 promoter. Yeast one-hybrid (Y1H) and dual-luciferase reporter (DLR) demonstrate that PpGATA21 can bind to the promoter of PpGA2ox7 and activate its expression. Overall, PpGATA21 activates the expression of the GA-related gene PpGA2ox7, resulting in reduced GA levels and consequent dwarfing of plants mediated by C. humilis. This study provides new insights into the mechanisms of C. humilis and offers a scientific foundation for the dwarfing and high-density cultivation of peach trees.

Unlocking Nature's Rhythms: Insights into Secondary Metabolite Modulation by the Circadian Clock

Plants, like many other living organisms, have an internal timekeeper, the circadian clock, which allows them to anticipate photoperiod rhythms and environmental stimuli to optimally adjust plant growth, development, and fitness. These fine-tuned processes depend on the interaction between environmental signals and the internal interactive metabolic network regulated by the circadian clock. Although primary metabolites have received significant attention, the impact of the circadian clock on secondary metabolites remains less explored. Transcriptome analyses revealed that many genes involved in secondary metabolite biosynthesis exhibit diurnal expression patterns, potentially enhancing stress tolerance. Understanding the interaction mechanisms between the circadian clock and secondary metabolites, including plant defense mechanisms against stress, may facilitate the development of stress-resilient crops and enhance targeted management practices that integrate circadian agricultural strategies, particularly in the face of climate change. In this review, we will delve into the molecular mechanisms underlying circadian rhythms of phenolic compounds, terpenoids, and N-containing compounds.

GIGANTEA Unveiled: Exploring Its Diverse Roles and Mechanisms

GIGANTEA (GI) is a conserved nuclear protein crucial for orchestrating the clock-associated feedback loop in the circadian system by integrating light input, modulating gating mechanisms, and regulating circadian clock resetting. It serves as a core component which transmits blue light signals for circadian rhythm resetting and overseeing floral initiation. Beyond circadian functions, GI influences various aspects of plant development (chlorophyll accumulation, hypocotyl elongation, stomatal opening, and anthocyanin metabolism). GI has also been implicated to play a pivotal role in response to stresses such as freezing, thermomorphogenic stresses, salinity, drought, and osmotic stresses. Positioned at the hub of complex genetic networks, GI interacts with hormonal signaling pathways like abscisic acid (ABA), gibberellin (GA), salicylic acid (SA), and brassinosteroids (BRs) at multiple regulatory levels. This intricate interplay enables GI to balance stress responses, promoting growth and flowering, and optimize plant productivity. This review delves into the multifaceted roles of GI, supported by genetic and molecular evidence, and recent insights into the dynamic interplay between flowering and stress responses, which enhance plants' adaptability to environmental challenges.