G protein controls stress readiness by modulating transcriptional and metabolic homeostasis in Arabidopsis thaliana and Marchantia polymorpha

Genome-Wide Identification of the GS3 Gene Family and the Influence of Natural Variations in BnGS3-3 on Salt and Cold Stress Tolerance in Brassica napus

Saline-alkali stress and cold damage significantly impact the yield of Brassica napus. G proteins play a crucial role in plant resistance to abiotic stresses, and research on G proteins in Brassica napus (rapeseed) is still in its early stages. In this study, we employed bioinformatics tools to systematically investigate the basic physicochemical properties, phylogenetic relationships, distribution, gene structure, cis-regulatory elements, and expansion patterns of the GS3 gene family in Brassica napus. Additionally, reverse transcription polymerase chain reaction (RT-PCR) was used to analyze the response of the BnGS3-3 gene to salt and low-temperature stresses. Natural variations were found in the promoter region of BnGS3-3. By conducting a promoter-driven luciferase (LUC) assay, the relationship between natural variations in the BnGS3-3 promoter and salt and cold tolerance was analyzed. Furthermore, the impact of these natural variations on flowering time, root length, and yield was explored using phenotypic data from a population. Our research results aim to provide insights into the function and molecular mechanisms of BnGS3-3 in Brassica napus, and to offer valuable genetic resources for molecular breeding to improve salt and low-temperature tolerance in Brassica napus.

The G-protein β subunit SlGB1 regulates tyramine-derived phenolamide metabolism for shoot apex growth and development in tomato

The shoot apex is a critical determinant of plant growth, development, morphology, and yield. The G-protein β subunit (Gβ) is an essential regulator of apical meristem dynamics, yet its precise mechanism of action remains unclear, with notable interspecific variation. This study reveals that in the dicot tomato (Solanum lycopersicum), Gβ subunit mutants (Slgb1) display abnormal shoot morphogenesis and, in severe cases, shoot apex death. Such a phenotype has also been observed in monocot species, like maize (Zea mays) and rice (Oryza sativa), but not in the model dicot Arabidopsis (Arabidopsis thaliana). Using integrated multiomics and liquid chromatography-mass spectrometry, we identified a significant upregulation in tyramine-derived phenolamides in Slgb1 mutants, particularly N-p-trans-coumaroyltyramine (N-P-CT) and N-trans-feruloyltyramine (N-FT). Biochemical and genetic assays pinpointed tyramine hydroxycinnamoyl transferases (THTs) as the enzymes catalyzing N-P-CT and N-FT biosynthesis, with THT8 overexpression inducing shoot apex death. Comparative genomic analysis revealed the presence of a THT-mediated tyramine-derived phenolamide metabolic pathway in species exhibiting gb1 mutant-associated apex death, which is notably absent in Arabidopsis. Protein interaction assays showed that SlGB1 interacts with bHLH79 at the cell membrane and cytoplasm, thereby attenuating the bHLH79-MYB10 interaction within the nucleus, leading to altered THT expression and phenolamide biosynthesis. This study unravels the molecular mechanisms by which SlGB1 governs tomato shoot apex growth and development, highlighting interspecific differences critical for developing breeding strategies aimed at optimizing shoot apex architecture.

Genome-Wide Identification and Expression Analysis of the G-Protein Gene Family in Barley Under Abiotic Stresses

Heterotrimeric G-proteins are fundamental signal transducers highly conserved in plant species, which play crucial roles in regulating plant growth, development, and responses to abiotic stresses. Identification of G-protein members and their expression patterns in plants are essential for improving crop resilience against environmental stresses. Here, we identified eight heterotrimeric G-protein genes localized on four chromosomes within the barley genome by using comprehensive genome-wide analysis. Phylogenetic analysis classified these genes into four distinct subgroups with obvious evolutionary relationships. Further analysis on gene structure, protein motif, and structure indicated that G-proteins within each evolutionary branch exhibited similar exon-intron organization, conserved motif patterns, and structural features. Collinearity analysis showed no significant collinear relationships among those G-protein genes, indicating a unique evolutionary trajectory within barley. Moreover, cis-regulatory elements detected in the upstream sequences of these genes were involved in response to plant hormones and signaling molecules. Expression analyses revealed tissue-specific expression patterns and differential regulation in response to abiotic stresses. The expression patterns of G-protein genes were further validated using a quantitative real-time PCR (qRT-PCR) technique, indicating the reliability of transcriptomic data, as well as special responses to salt, drought, and waterlogging stresses. These findings may provide underlying mechanisms by which G-protein genes participate in salt tolerance of barley, and also highlight candidate genes for potential genetic engineering applications in improving crop resilience to salinity stress.

Proteomic dynamics revealed sex-biased responses to combined heat-drought stress in Marchantia

Recent studies have documented plant responses to climate change extensively, particularly to single-stress exposures. However, critical factors for stress survival, such as sexual differentiation, are not often considered. The dioicous Marchantia polymorpha stands as an evolutionary milestone, potentially preserving ancestral traits from the early colonizers. In this study, we employed proteomic analyses complemented with physiological monitoring to investigate combined heat and drought responses in Tak-1 (male) and Tak-2 (female) accessions of this liverwort. Additionally, targeted transcriptomics was conducted using different natural populations from contrasting environments. Our findings revealed sex-biased dynamics among natural accessions, particularly evident under control conditions and during early stress responses. Although Tak-2 exhibited greater diversity than Tak-1 under control conditions, male accession demonstrated distinct and more rapid stress sensing and signaling. These differences in stress response appeared to be strongly related to sex-specific plasticity influenced by geoclimatic origin. Furthermore, we established distinct protein gene ages and genomic distribution trends, underscoring the importance of protein diversification over time. This study provides an evolutionary perspective on sexual divergence and stress emergence employing a systems biology approach, which allowed for the establishment of global and sex-specific interaction networks in the stress response.

Hyperspectral imaging of liverwort Marchantia polymorpha identifies MpWRKY10 as a key regulator defining Foliar pigmentation patterns

Foliar pigmentation patterns vary among plant species and growth conditions. In this study, we utilize hyperspectral imaging to assess foliar pigmentation in the bryophyte Marchantia polymorpha under nutrient stress and identify associated genetic factors. Using singular value decomposition (SVD) for feature selection, we quantitate color variations induced by deficiencies in phosphate, nitrate, magnesium, calcium, and iron. Pseudo-colored thallus images show that disrupting MpWRKY10 causes irregular pigmentation with auronidin accumulation. Transcriptomic profiling shows that MpWRKY10 regulates phenylpropanoid pathway enzymes and R2R3-MYB transcription factors during phosphate deficiency, with MpMYB14 upregulation preceding pigment accumulation. MpWRKY10 is downregulated in older, pigmented thalli under phosphate deficiency but maintained in young thalli, where it suppresses pigmentation genes. This downregulation is absent in pigmented thalli due to aging. Comparative transcriptome analysis suggests similar WRKY and MYB roles in nutrient response and pigmentation in red-leaf lettuce, alluding to conserved genetic factors controlling foliar pigmentation patterns under nutrient deficiency.

Oryza CLIMtools: A Genome-Environment Association Resource Reveals Adaptive Roles for Heterotrimeric G Proteins in the Regulation of Rice Agronomic Traits

Modern crop varieties display a degree of mismatch between their current distributions and the suitability of the local climate for their productivity. To this end, we present Oryza CLIMtools (https://gramene.org/CLIMtools/oryza_v1.0/), the first resource for pan-genome prediction of climate-associated genetic variants in a crop species. Oryza CLIMtools consists of interactive web-based databases that allow the user to: i) explore the local environments of traditional rice varieties (landraces) in South-Eastern Asia, and; ii) investigate the environment by genome associations for 658 Indica and 283 Japonica rice landrace accessions collected from georeferenced local environments and included in the 3K Rice Genomes Project. We exemplify the value of these resources, identifying an interplay between flowering time and temperature in the local environment that is facilitated by adaptive natural variation in OsHD2 and disrupted by a natural variant in OsSOC1. Prior QTL analysis has suggested the importance of heterotrimeric G proteins in the control of agronomic traits. Accordingly, we analyzed the climate associations of natural variants in the different heterotrimeric G protein subunits. We identified a coordinated role of G proteins in adaptation to the prevailing Potential Evapotranspiration gradient and their regulation of key agronomic traits including plant height and seed and panicle length. We conclude by highlighting the prospect of targeting heterotrimeric G proteins to produce crops that are climate resilient.

An atypical heterotrimeric Gα and its interactome suggest an extra-large role in overcoming abiotic and biotic stress

Canonical heterotrimeric G-proteins (G-proteins) are comprised of Gα, Gβ, and Gγ subunits. G-proteins regulate multiple crucial plant growth and development processes, incorporating environmental responses. Besides Gα, Gβ and Gγ, the discovery of atypical Gα subunits termed as extra-large G-proteins or extra-large GTP-binding proteins (XLGs) makes G-protein signaling unique in plants. The C-terminus of XLG shares similarities with the canonical Gα subunits; the N-terminus harbors a nuclear localization signal (NLS) and is rich in cysteine. The earlier explorations suggest XLG's role in flowering, the development of embryos and seedlings, root morphogenesis, stamen development, cytokinin-induced development, stomatal opening and regulation of rice grain filling. The XLGs are also known to initiate signaling cascades that prime plants against a variety of abiotic and biotic stresses. They are also engaged in controlling several agronomic parameters such as rice panicle length, grain filling, grain size, and biomass, highlighting their potential contribution to crop improvement. The present review explores the remarkable properties of non-canonical Gα subunits (XLGs) and reflects on the various developmental, abiotic and biotic stress signaling pathways controlled by them. Moreover, the bottleneck dilemma of how a tiny handful of XLGs control a multiplicity of stress-responsive activities is partially resolved in this review by addressing the interaction of XLGs with different interacting proteins. XLG proteins presented in this review can be exploited to gain access to highly productive and stress-tolerant plants.