The CIB1 transcription factor regulates light- and heat-inducible cell elongation via a two-step HLH/bHLH system

Genome-Wide Identification and Role of the bHLH Gene Family in Dendrocalamus latiflorus Flowering Regulation

The basic helix-loop-helix (bHLH) gene family is a crucial regulator in plants, orchestrating various developmental processes, particularly flower formation, and mediating responses to hormonal signals. The molecular mechanism of bamboo flowering regulation remains unresolved, limiting bamboo breeding efforts. In this study, we identified 309 bHLH genes and divided them into 23 subfamilies. Structural analysis revealed that proteins in specific DlbHLH subfamilies are highly conserved. Collinearity analysis indicates that the amplification of the DlbHLH gene family primarily occurs through segmental duplications. The structural diversity of these duplicated genes may account for their functional variability. Many DlbHLHs are expressed during flower development, indicating the bHLH gene's significant role in this process. In the promoter region of DlbHLHs, different homeopathic elements involved in light response and hormone response co-exist, indicating that DlbHLHs are related to the regulation of the flower development of D. latiflorus.

Synthetic biology approaches for enhancing safety and specificity of CAR-T cell therapies for solid cancers

CAR-T cell therapies have been successful in treating numerous hematologic malignancies as the T cell can be engineered to target a specific antigen associated with the disease. However, translating CAR-T cell therapies for solid cancers is proving more challenging due to the lack of truly tumor-associated antigens and the high risk of off-target toxicities. To combat this, numerous synthetic biology mechanisms are being incorporated to create safer and more specific CAR-T cells that can be spatiotemporally controlled with increased precision. Here, we seek to summarize and analyze the advancements for CAR-T cell therapies with respect to clinical implementation, from the perspective of synthetic biology and immunology. This review should serve as a resource for further investigation and growth within the field of personalized cellular therapies.

GWAS identifies two important genes involved in Chinese chestnut weight and leaf length regulation

There are many factors that affect the yield of Chinese chestnut (Castanea mollissima), with single nut weight (SNW) being one of the most important. Leaf length is also related to Chinese chestnut yield. However, the genetic architecture and gene function associated with Chinese chestnut nut yield have not been fully explored. In this study, we performed genotyping by sequencing 151 Chinese chestnut cultivars, followed by a genome-wide association study (GWAS) on six horticultural traits. First, we analyzed the phylogeny of the Chinese chestnut and found that the Chinese chestnut cultivars divided into two ecotypes, a northern and southern cultivar group. Differences between the cultivated populations were found in the pathways of plant growth and adaptation to the environment. In the selected regions, we also found interesting tandemly arrayed genes that may influence Chinese chestnut traits and environmental adaptability. To further investigate which horticultural traits were selected, we performed a GWAS using six horticultural traits from 151 cultivars. Forty-five loci that strongly associated with horticultural traits were identified, and six genes highly associated with these traits were screened. In addition, a candidate gene associated with SNW, APETALA2 (CmAP2), and another candidate gene associated with leaf length (LL), CRYPTOCHROME INTERACTING BASIC HELIX-LOOP-HELIX 1 (CmCIB1), were verified in Chinese chestnut and Arabidopsis (Arabidopsis thaliana). Our results showed that CmAP2 affected SNW by negatively regulating cell size. CmCIB1 regulated the elongation of new shoots and leaves by inducing cell elongation, potentially affecting photosynthesis. This study provided valuable information and insights for Chinese chestnut breeding research.

Identification and Characterization of PRE Genes in Moso Bamboo (Phyllostachys edulis)

Basic helix-loop-helix (bHLH)/HLH transcription factors are involved in various aspects of the growth and development of plants. Here, we identified four HLH genes, PePRE1-4, in moso bamboo plants that are homologous to Arabidopsis PRE genes. In bamboo seedlings, PePRE1/3 were found to be highly expressed in the internode and lamina joint by using quantitative RT-PCR analysis. In the elongating internode of bamboo shoots, PePRE genes are expressed at higher levels in the basal segment than in the mature top segment. Overexpression of PePREs (PePREs-OX) in Arabidopsis showed longer petioles and hypocotyls, as well as earlier flowering. PePRE1 overexpression restored the phenotype due to the deficiency of AtPRE genes caused by artificial micro-RNA. PePRE1-OX plants showed hypersensitivity to propiconazole treatment compared with the wild type. In addition, PePRE1/3 but not PePRE2/4 proteins accumulated as punctate structures in the cytosol, which was disrupted by the vesicle recycling inhibitor brefeldin A (BFA). PePRE genes have a positive function in the internode elongation of moso bamboo shoots, and overexpression of PePREs genes promotes flowering and growth in Arabidopsis. Our findings provided new insights about the fast-growing mechanism of bamboo shoots and the application of PRE genes from bamboo.

Diverse flowering responses subjecting to ambient high temperature in soybean under short-day conditions

Flowering time is one of important agronomic traits determining the crop yield and affected by high temperature. When facing high ambient temperature, plants often initiate early flowering as an adaptive strategy to escape the stress and ensure successful reproduction. However, here we find opposing ways in the short-day crop soybean to respond to different levels of high temperatures, in which flowering accelerates when temperature changes from 25 to 30 °C, but delays when temperature reaches 35 °C under short day. phyA-E1, possibly photoperiodic pathway, is crucial for 35 °C-mediated late flowering, however, does not contribute to promoting flowering at 30 °C. 30 °C-induced up-regulation of FT2a and FT5a leads to early flowering, independent of E1. Therefore, distinct responsive mechanisms are adopted by soybean when facing different levels of high temperatures for successful flowering and reproduction.

HFR1, a bHLH Transcriptional Regulator from Arabidopsis thaliana, Improves Grain Yield, Shade and Osmotic Stress Tolerances in Common Wheat

Common wheat, Triticum aestivum, is the most widely grown staple crop worldwide. To catch up with the increasing global population and cope with the changing climate, it is valuable to breed wheat cultivars that are tolerant to abiotic or shade stresses for density farming. Arabidopsis LONG HYPOCOTYL IN FAR-RED 1 (AtHFR1), a photomorphogenesis-promoting factor, is involved in multiple light-related signaling pathways and inhibits seedling etiolation and shade avoidance. We report that overexpression of AtHFR1 in wheat inhibits etiolation phenotypes under various light and shade conditions, leading to shortened plant height and increased spike number relative to non-transgenic plants in the field. Ectopic expression of AtHFR1 in wheat increases the transcript levels of TaCAB and TaCHS as observed previously in Arabidopsis, indicating that the AtHFR1 transgene can activate the light signal transduction pathway in wheat. AtHFR1 transgenic seedlings significantly exhibit tolerance to osmotic stress during seed germination compared to non-transgenic wheat. The AtHFR1 transgene represses transcription of TaFT1, TaCO1, and TaCO2, delaying development of the shoot apex and heading in wheat. Furthermore, the AtHFR1 transgene in wheat inhibits transcript levels of PHYTOCHROME-INTERACTING FACTOR 3-LIKEs (TaPIL13, TaPIL15-1B, and TaPIL15-1D), downregulating the target gene STAYGREEN (TaSGR), and thus delaying dark-induced leaf senescence. In the field, grain yields of three AtHFR1 transgenic lines were 18.2–48.1% higher than those of non-transgenic wheat. In summary, genetic modification of light signaling pathways using a photomorphogenesis-promoting factor has positive effects on grain yield due to changes in plant architecture and resource allocation and enhances tolerances to osmotic stress and shade avoidance response.

PIFs- and COP1-HY5-mediated temperature signaling in higher plants

Plants have to cope with the surrounding changing environmental stimuli to optimize their physiological and developmental response throughout their entire life cycle. Light and temperature are two critical environmental cues that fluctuate greatly during day-night cycles and seasonal changes. These two external signals coordinately control the plant growth and development. Distinct spectrum of light signals are perceived by a group of wavelength-specific photoreceptors in plants. PIFs and COP1-HY5 are two predominant signaling hubs that control the expression of a large number of light-responsive genes and subsequent light-mediated development in plants. In parallel, plants also transmit low or warm temperature signals to these two regulatory modules that precisely modulate the responsiveness of low or warm temperatures. The core component of circadian clock ELF3 integrates signals from light and warm temperatures to regulate physiological and developmental processes in plants. In this review, we summarize and discuss recent advances and progresses on PIFs-, COP1-HY5- and ELF3-mediated light, low or warm temperature signaling, and highlight emerging insights regarding the interactions between light and low or warm temperature signal transduction pathways in the control of plant growth.

MicroProteins: Dynamic and accurate regulation of protein activity

Proteins usually assemble oligomers or high-order complexes to increase their efficiency and specificity in biological processes. The dynamic equilibrium of complex formation and disruption imposes reversible regulation of protein function. MicroProteins are small, single-domain proteins that directly bind target protein complexes and disrupt their assembly. Growing evidence shows that microProteins are efficient regulators of protein activity at the post-translational level. In the last few decades, thousands of plant microProteins have been predicted by computational approaches, but only a few have been experimentally validated. Recent studies highlighted the mechanistic working modes of newly-identified microProteins in Arabidopsis and other plant species. Here, we review characterized microProteins, including their biological roles, regulatory targets, and modes of action. In particular, we focus on microProtein-directed allosteric modulation of key components in light signaling pathways, and we summarize the biogenesis and evolutionary trajectory of known microProteins in plants. Understanding the regulatory mechanisms of microProteins is an important step towards potential utilization of microProteins as versatile biotechnological tools in crop bioengineering.

Overexpression of HLH4 Inhibits Cell Elongation and Anthocyanin Biosynthesis in Arabidopsis thaliana

In plants, many basic helix-loop-helix (bHLH) transcription factors are involved in controlling cell elongation. Three bHLH proteins, PACLOBTRAZOL RESISTANCE1 (PRE1), Cryptochrome Interacting Basic Helix-loop-helix 5 (CIB5), and Arabidopsis ILI1 binding bHLH1 (IBH1) form a triantagonistic system that antagonistically regulates cell elongation in a competitive manner. In this study, we identified a new player, HLH4, related to IBH1, that negatively regulates cell elongation in Arabidopsis thaliana. Overexpression of HLH4 causes dwarf and dark green phenotypes and results in the downregulation of many key regulatory and enzymatic genes that participate in the anthocyanin biosynthetic pathway. HLH4 interacts with CIB5 and PRE1. By interacting with CIB5, HLH4 interferes with the activity of CIB5, and thus inhibiting the transcription of cell elongation-related genes regulated by CIB5, including EXPANSINS8 and 11 (EXP8 and EXP11) and indole-3-acetic acid 7 and 17 (IAA7 and IAA17). The interference of HLH4 on CIB5 is counteracted by PRE1, in which these bHLH proteins form a new tri-antagonistic system.

Basic Protein Modules Combining Abscisic Acid and Light Signaling in Arabidopsis

It is generally accepted that plants use the complex signaling system regulated by light and abscisic acid (ABA) signaling components to optimize growth and development in different situations. The role of ABA-light interactions is evident in the coupling of stress defense reactions with seed germination and root development, maintaining of stem cell identity and stem cell specification, stem elongation and leaf development, flowering and fruit formation, senescence, and shade avoidance. All these processes are regulated jointly by the ABA-light signaling system. Although a lot of work has been devoted to ABA-light signal interactions, there is still no systematic description of central signaling components and protein modules, which jointly regulate plant development. New data have emerged to promote understanding of how ABA and light signals are integrated at the molecular level, representing an extensively growing area of research. This work is intended to fill existing gaps by using literature data combined with bioinformatics analysis.