Tightly controlled expression of OsbHLH35 is critical for anther development in rice

bHLH-regulated routes in anther development in rice and Arabidopsis

Anther development is a complex process essential for plant reproduction and crop yields. In recent years, significant progress has been made in the identification and characterization of the bHLH transcription factor family involved in anther regulation in rice and Arabidopsis, two extensively studied model plants. Research on bHLH transcription factors has unveiled their crucial function in controlling tapetum development, pollen wall formation, and other anther-specific processes. By exploring deeper into regulatory mechanisms governing anther development and bHLH transcription factors, we can gain important insights into plant reproduction, thereby accelerating crop yield improvement and the development of new plant breeding strategies. This review provides an overview of the current knowledge on anther development in rice and Arabidopsis, emphasizing the critical roles played by bHLH transcription factors in this process. Recent advances in gene expression analysis and functional studies are highlighted, as they have significantly enhanced our understanding of the regulatory networks involved in anther development.

Overexpression of SlPRE3 alters the plant morphologies in Solanum lycopersicum

KEY MESSAGE

Overexpression of SlPRE3 is detrimental to the photosynthesis and alters plant morphology and root development. SlPRE3 interacts with SlAIF1/SlAIF2/SlPAR1/SlIBH1 to regulate cell expansion. Basic helix-loop-helix (bHLH) transcription factors play crucial roles as regulators in plant growth and development. In this study, we isolated and characterized SlPRE3, an atypical bHLH transcription factor gene. SlPRE3 exhibited predominant expression in the root and moderate expression in the senescent leaves. Comparative analysis with the wild type revealed significant differences in plant morphology in the 35S:SlPRE3 lines. These differences included increased internode length, rolling leaves with reduced chlorophyll accumulation, and elongated yet fewer adventitious roots. Additionally, 35S:SlPRE3 lines displayed elevated levels of GA3 (gibberellin A3) and reduced starch accumulation. Furthermore, utilizing the Y2H (Yeast two-hybrid) and the BiFC (Bimolecular Fluorescent Complimentary) techniques, we identified physical interactions between SlPRE3 and SlAIF1 (ATBS1-interacting factor 1)/SlAIF2 (ATBS1-interacting factor 2)/SlPAR1 (PHYTOCHROME RAPIDLY REGULATED 1)/SlIBH1 (ILI1-binding bHLH 1). RNA-seq analysis of root tissues revealed significant alterations in transcript levels of genes involved in gibberellin metabolism and signal transduction, cell expansion, and root development. In summary, our study sheds light on the crucial regulatory role of SlPRE3 in determining plant morphology and root development.

Effect of temperature on betacyanins synthesis and the transcriptome of Suaeda salsa

Introduction

Suaeda salsa (Linn.) Pall. is an important tourist resource and ecological restoration species in coastal wetlands. Environmental factors such as low temperature, darkness, phytohormone, salt stress and seawater flflooding, and light can induce betalain synthesis in S. salsa, which plays an important role in plant adaptation to abiotic stress processes and in shaping the beautiful "red beach" landscape.

Methods

In this study, Illumina sequencing was used to profifile the transcriptome sequence (RNA-Seq) of S. salsa leaves at different temperatures (5° C, 10°C, 15°C, 20°C, 25°C, and 30°C) and to validate differentially expressed genes (DEGs) indicated by real-time PCR (RT-qPCR).

Results

The betacyanin content was highest in S. salsa leaves at 15°C. Transcription group data showed that compared to the control group (15°C), the "betacyanin biosynthesis pathway" was signifificantly enriched in the fifive different temperature groups. KEGG analysis showed that the DEGs were mainly involved in pathways of phenylpropanoid biosynthesis, carbon fifixation in photosynthetic organisms, flflavonoid biosynthesis, and betacyanin biosynthesis. Among the key enzymes involved in biosynthesis of betacyanin, genes for tyrosinase, CYP76AD1 and 4,5-DOPA dioxygenase were signifificantly upregulated and most abundantly expressed at 15°C. It is possible that the gene for betacyanin synthesis from S. salsa is primarily regulated by the MYB1R1 and MYB1 transcription factor. Four DEGs were randomly selected for quantitative PCR analysis, and DEG expression was generally consistent with the RNA-Seq data, verifying the validity of the transcriptome sequencing data.

Discussion

Relative to other temperatures, 15°C was optimum for S. salsa betacyanin synthesis, and this provides a theoretical reference for coastal wetland ecological remediation, reveals mechanisms of S. salsa discoloration, and further mines its potential application for landscape vegetation.

Genome-Wide Urea Response in Rice Genotypes Contrasting for Nitrogen Use Efficiency

Rice is an ideal crop for improvement of nitrogen use efficiency (NUE), especially with urea, its predominant fertilizer. There is a paucity of studies on rice genotypes contrasting for NUE. We compared low urea-responsive transcriptomes of contrasting rice genotypes, namely Nidhi (low NUE) and Panvel1 (high NUE). Transcriptomes of whole plants grown with media containing normal (15 mM) and low urea (1.5 mM) revealed 1497 and 2819 differentially expressed genes (DEGs) in Nidhi and Panvel1, respectively, of which 271 were common. Though 1226 DEGs were genotype-specific in Nidhi and 2548 in Panvel1, there was far higher commonality in underlying processes. High NUE is associated with the urea-responsive regulation of other nutrient transporters, miRNAs, transcription factors (TFs) and better photosynthesis, water use efficiency and post-translational modifications. Many of their genes co-localized to NUE-QTLs on chromosomes 1, 3 and 9. A field evaluation under different doses of urea revealed better agronomic performance including grain yield, transport/uptake efficiencies and NUE of Panvel1. Comparison of our urea-based transcriptomes with our previous nitrate-based transcriptomes revealed many common processes despite large differences in their expression profiles. Our model proposes that differential involvement of transporters and TFs, among others, contributes to better urea uptake, translocation, utilization, flower development and yield for high NUE.

Basic Helix-Loop-Helix Transcription Factors: Regulators for Plant Growth Development and Abiotic Stress Responses

Plant basic helix-loop-helix (bHLH) transcription factors are involved in many physiological processes, and they play important roles in the abiotic stress responses. The literature related to genome sequences has increased, with genome-wide studies on the bHLH transcription factors in plants. Researchers have detailed the functionally characterized bHLH transcription factors from different aspects in the model plant Arabidopsis thaliana, such as iron homeostasis and abiotic stresses; however, other important economic crops, such as rice, have not been summarized and highlighted. The bHLH members in the same subfamily have similar functions; therefore, unraveling their regulatory mechanisms will help us to identify and understand the roles of some of the unknown bHLH transcription factors in the same subfamily. In this review, we summarize the available knowledge on functionally characterized bHLH transcription factors according to four categories: plant growth and development; metabolism synthesis; plant signaling, and abiotic stress responses. We also highlight the roles of the bHLH transcription factors in some economic crops, especially in rice, and discuss future research directions for possible genetic applications in crop breeding.

Compensatory Effect of the ScGrf3-2R Gene in Semi-Dwarf Spring Triticale (x Triticosecale Wittmack)

The dwarfness in many triticale cultivars is provided by the dominant Ddw1 (Dominant dwarf 1) allele found in rye. However, along with conferring semi-dwarf phenotype to improve resistance to lodging, this gene also reduces grain size and weight and delays heading and flowering. Grf (Growth-regulating factors) genes are plant-specific transcription factors that regulate plant growth, including stem growth, in terms of length and thickness, and leaf and fruit size. In this work, we partially sequenced the rye gene ScGrf3 on chromosome 2R homologous to the wheat Grf3 gene, and found multiple polymorphisms in intron 3 and exon 4 complying with two alternative alleles (haplotypes ScGrf3-2Ra and ScGrf3-2Rb). For the identification of these, we developed a codominant PCR marker. Using a new marker, we studied the effect of ScGrf3-2R alleles in combination with the Ddw1 dwarf gene on economically valuable traits in F₄ and F₅ recombinant lines of spring triticale from the hybrid combination Valentin 90 x Dublet, grown in the Non-Chernozem zone for 2 years. Allele ScGrf3-2Ra was associated with greater thousand-grain weight, higher spike productivity, and earlier heading and flowering, which makes ScGrf3-2R a perspective compensator for negative effects of Ddw1 on these traits and increases prospects for its involvement in breeding semi-dwarf cultivars of triticale.

Genome-wide identification and transcriptional profiling of the basic helix-loop-helix gene family in tung tree (Vernicia fordii)

The basic helix-loop-helix (bHLH) transcription factor gene family is one of the largest gene families and is extensively involved in plant growth, development, biotic and abiotic stress responses. Tung tree (Vernicia fordii) is an economically important woody oil plant that produces tung oil rich in eleostearic acid. However, the characteristics of the bHLH gene family in the tung tree genome are still unclear. Hence, VfbHLHs were first searched at a genome-wide level, and their expression levels in various tissues or under low temperature were investigated systematically. In this study, we identified 104 VfbHLHs in the tung tree genome, and these genes were classified into 18 subfamilies according to bHLH domains. Ninety-eight VfbHLHs were mapped to but not evenly distributed on 11 pseudochromosomes. The domain sequences among VfbHLHs were highly conserved, and their conserved residues were also identified. To explore their expression, we performed gene expression profiling using RNA-Seq and RT-qPCR. We identified five, 18 and 28 VfbHLH genes in female flowers, male flowers and seeds, respectively. Furthermore, we found that eight genes (VfbHLH29, VfbHLH31, VfbHLH47, VfbHLH51, VfbHLH57, VfbHLH59, VfbHLH70, VfbHLH72) were significant differential expressed in roots, leaves and petioles under low temperature stress. This study lays the foundation for future studies on bHLH gene cloning, transgenes, and biological mechanisms.

The Roles of microRNA-Long Non-coding RNA-mRNA Networks in the Regulation of Leaf and Flower Development in Liriodendron chinense

The leaf and the flower are vital plant organs owing to their roles in photosynthesis and reproduction. Long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and transcription factors (TFs) are very important to the development of these organs. Liriodendron chinense is a common ornamental tree species in southern China with an unusual leaf shape and tulip-like flowers. The genetic mechanisms underlying leaf and flower development in L. chinense and the miRNA-lncRNA-TF regulatory networks are poorly studied. Through the integration and analysis of different types of sequencing data, we identified the miRNA-lncRNA-TF regulatory networks that were related to leaf and flower development. These networks contained 105 miRNAs, 258 lncRNAs, 393 TFs, and 22 endogenous target mimics. Notably, lch-lnc7374-miR156h-SPL3 and lch-lnc7374-miR156j-SPL9 were potential regulators of stamen and pistil development in L. chinense, respectively. miRNA-lncRNA-mRNA regulatory networks were shown to impact anther development, male and female fertility, and petal color by regulating the biosynthesis of phenylpropanoid metabolites. Phenylpropanoid metabolite biosynthesis genes and TFs that were targeted by miRNAs and lncRNAs were differentially expressed in the leaf and flower. Moreover, RT-qPCR analysis confirmed 22 differentially expressed miRNAs, among which most of them showed obvious leaf or flower specificity; miR157a-SPL and miR160a-ARF module were verified by using RLM-RACE, and these two modules were related to leaf and flower development. These findings provide insight into the roles of miRNA-lncRNA-mRNA regulatory networks in organ development and function in L. chinense, and will facilitate further investigation into the regulatory mechanisms of leaf and flower development in L. chinense.