CitMYB84: A promising transcription factor for the citrus fight against Candidatus Liberibacter asiaticus.

Environmental control of flowering through alternative splicing of FLC and COOLAIR.

AtGATA11 activates AtBCCP2 transcription in Arabidopsis in response to NaHCO3 stress.

Overexpression of a low-affinity fructokinase MdFRK1 leads to enhanced accumulation of fructose in apple calli.

Loss of CmMAIL2 compromises chloroplast function but permits developmental progression in melon.

Identification and functional analysis of GbMYB15 as a negative regulator in flavonoid biosynthesis of Ginkgo biloba.

Ferroportin transporters contribute to nickel hyperaccumulation in Odontarrhena chalcidica.

Molecular determinants of sugar donor selectivity in MGD1, the major galactolipid synthase in Arabidopsis thaliana.

Drought response in plants is complex, involving integration across a range of physiological processes. However, our knowledge of how different mechanisms of drought response are linked at the genetic level is limited. We investigated multi-trait adaptation in Arabidopsis thaliana from the Cape Verde Islands (CVI). Using a high-throughput phenotyping platform that minimizes spatial heterogeneity, we measured variation in rosette area, growth rate, leaf color, water use efficiency (WUE), and stomatal patterning under precisely controlled water conditions. Relative to the Moroccan outgroup, CVI populations evolved earlier flowering, a smaller rosette size with faster growth, and reduced WUE, consistent with drought escape adaptation. Genome-wide association mapping revealed evidence for pleiotropy involving MPK12 (WUE, rosette area, growth rate, and leaf color), NHL26 (WUE and leaf color), SUVH4 (stomatal patterning, rosette area, and leaf color), and FRI (flowering time, WUE, and leaf color), along with an enrichment of signals in ABA response. This study advances our knowledge of the genetic mechanisms driving plant adaptation to a novel precipitation environment. By identifying key genetic components and their contributions to multi-trait adaptation, our findings offer insights into how plants respond to environmental challenges and contribute to predicting plant responses to future climate change.

Plant-specific membrane receptor kinases with structurally diverse extracellular domains regulate key processes in plant growth, development, immunity and symbiosis. Structural studies of these glycoproteins are often hampered by the limited quantities in which they can be obtained. Here, we describe the leucine-rich repeat (LRR) crystallization screen, which has enabled the successful crystallization and structure determination of multiple receptor kinase ectodomains, including ligand- and co-receptor-bound complexes. As an example, we report the 1.5 Å resolution crystal structure of the LRR domain of STRUBBELIG-RECEPTOR FAMILY 6 (SRF6) from Arabidopsis thaliana. The SRF6 ectodomain contains seven LRRs and a disulfide-bond-stabilized N-terminal capping domain but lacks the canonical C-terminal cap and the N-glycosylation pattern typically found in other family members. Previously reported protein-protein interactions between the SRF6 and SRF7 ectodomains and the receptor kinases BRI1, BRL1, BRL3, SERK3 and BIR1-BIR3 could not be confirmed by quantitative isothermal titration calorimetry and grating-coupled interferometry assays, suggesting that these structurally conserved LRR receptor kinases may have signalling functions outside the brassinosteroid pathway.

Chitooligosaccharides, such as chitin, are essential components of fungal cell walls and have thus naturally been selected as microbe-associated molecular patterns detected by plants to initiate defense mechanisms. These molecules are typically recognized by the lysin motif receptor-like kinases (LysM RLKs) at the plasma membrane. While chitin perception is well elucidated in Arabidopsis thaliana and other plant species, the recognition mechanisms of its deacetylated form, chitosan, remain poorly investigated despite its use as a biocontrol strategy to protect crops against pathogens. Here, we investigated the role of the two grapevine orthologs of AtLYK4, which participate in the tripartite complex for chitin perception in A. thaliana. Using a dual approach consisting of the functional complementation of the atlyk4/5 double mutant and CRISPR-Cas9 genome editing in Vitis vinifera, we showed that VvLYK4-2 is involved in both chitosan- and chitin-induced immune responses, encompassing MAPK phosphorylation and defense gene expression. Furthermore, grapevine in vitro plantlets lacking VvLYK4-2 exhibited a significantly reduced response to chitosan while retaining a low-intensity response to chitin, potentially due to the presence of VvLYK5-1. Finally, VvLYK4-2 produced in a heterologous system showed binding to chitosan oligomers and, to a lesser extent, to chitin oligomers. These findings indicate that this pattern recognition receptor plays a crucial role in the perception of chitosan oligomers and has thus potential for selective breeding purposes. This discovery may also help to better understand the partial lack of efficacy of chitosan-based plant defense stimulants used in viticulture.

SUPERROOT1 is not the only C-S lyase capable to contribute to glucosinolate biosynthesis in Arabidopsis thaliana.

Plants respond to mechanical stimuli by a rapid increase in cytosolic calcium. The intensity and kinetics of the calcium changes define calcium signatures important for biological responses. In this study, we determine the properties of a calcium-permeable force-gated channel localized at the plasma membrane called Rapid Mechanically Activated (RMA). Using patch clamp and pressure clamp, we characterized the kinetics of the Arabidopsis thaliana RMA channel upon stimulation by pressure pulses applied onto the plasma membrane. Combining pressure pulse protocols at different frequencies with modeling, we investigated the channel's capacity to transduce high frequency mechanical stimuli. The RMA channel rapidly activates in response to membrane tension, then it inactivates during prolonged stimulation. Upon repeated stimulations, the RMA current amplitude decreases irreversibly indicating that it undergoes attenuation. The channel kinetics were modeled with four chemical states and the model predicts that it behaves as a pass band filter in the 10 Hz-1 kHz range. In conclusion, due to its activation/inactivation, the RMA channel is a candidate for mediating cytosolic calcium signaling in response to mechanostimulation. Its attenuation and filtering properties suggest its involvement in the transduction of high frequency mechanical stimulation, such as those produced by insects' vibrations.

Jasmonates (JAs)-mediated pathways are central signaling hubs in plant defense responses. However, the identification of mobile and nonmobile signals involved in downstream systemic signaling is still less studied. Here, we investigate the role of the jasmonic acid-isoleucine (JA-Ile) conjugating enzyme, JAR1, in shifting wound-induced local and systemic metabolic profiles using liquid chromatography mass spectrometry (LC-MS/MS) for untargeted metabolomics, and the mobility of JA-Ile in wound-induced local and systemic defense using LC-MS/MS for targeted JAs analysis in Arabidopsis thaliana leaves. The use of jarin-1, a specific inhibitor of JA-Ile biosynthesis, suggested that JA-Ile was synthesized de novo in the particular tissues, rather than being a mobile signal. In addition, inhibition of JAR1 enzyme activity affected an array of downstream metabolic pathways, locally and systemically, such as amino acids and carbohydrate metabolism. This study suggests that the occurrence and spread of local and systemic downstream signals very likely depend on JAR1 activity, and this enzyme exclusively regulates a series of metabolic pathways under both wounding and nonwounding conditions.

The organic cation choline is essential for eukaryotic metabolism. Recently, the feline leukemia virus subgroup C receptor-related (FLVCR, SLC49) family was demonstrated as central for basal choline transport, questioning the role of the choline transporter-like (CTL, SLC44) family in this capacity. Here, we use Xenopus laevis oocytes to confirm that FLVCR1 (SLC49A1) and FLVCR2 (SLC49A2) proteins are choline transporters. CTL1 (SLC44A1) does not transport choline under the same conditions, supported by other CTL proteins, Arabidopsis thaliana CherI and Saccharomyces cerevisiae PNS1, which also display no choline transport activity. We present the atomic structures of FLVCR2, CTL1, and PNS1. The 3.4 Å cryo-EM structure of FLVCR2 has choline in the binding pocket. The 3.3 Å cryo-EM structure of CTL1 and the 2.7 Å crystal structure of PNS1 reveal an unusual protein fold, weakly related to the mitochondrial carrier family (SLC25). The unusual fold appears incompatible with transmembrane transport and implies a different and, so far, unknown function for CTL proteins. Our results support FLVCR proteins as choline transporters and suggest a nontransport role for CTL proteins.

Root hairs (RH), single cells that develop from the root epidermis, are key for anchorage in the soil and the absorption of water, macronutrients, and micronutrients as well as for establishing symbiotic relationships with soil microorganisms. RH has become a significant cell model system for investigating plant growth and the mechanisms by which plants adjust their growth in response to intrinsic cellular and environmental stimuli. Here, we focus on our current understanding of the molecular mechanisms that govern the growth of Arabidopsis thaliana RH at the intersection of environmental responses (e.g., nutrients like nitrate and phosphate, as well as microorganisms), hormonal signals (e.g., auxin, ethylene, jasmonic acid, etc) and the main transcriptional regulators. The regulation of RH development is governed by several transcription factors including the master regulators RHD6 and RSL2/RSL4, which are subject to stringent control at multiple levels. In this review, we summarize the latest advances in the signaling integration pathways that may increase our capacity to enhance nutrient uptake by the roots in the context of abiotic stresses for a more sustainable agriculture.

Camellia sinensis (L.) O. Kuntze exhibits severely restricted growth at low temperatures, resulting in reduced tea leaf yield and quality. BRI1-EMS-suppressor (BES) transcription factors, as key components of the brassinosteroids (BR) signaling pathway, are highly homologous to BZR and jointly regulate plants' adaptation to environmental stress. In this study, the CsBES1-14 gene was successfully cloned and identified from the transcriptome database of tea plant. Biochemical analyses identified CsBES1-14 as a nuclear localized transcriptional activator, and BR and low temperature induced its expression. Arabidopsis thaliana plants overexpressing CsBES1-14 exhibited increased chilling tolerance by promoting root growth and increasing the expression of cold responsive genes. Conversely, the suppression of CsBES1-14 through virus-induced gene silencing (VIGS) in tea plant notably impaired cold tolerance. Transcription Factor-centered Yeast One-Hybrid screening identified CsCOR413 as a downstream target, and electrophoretic mobility shift assays confirmed the direct binding of CsBES1-14 to specific cis-elements in the CsCOR413 promoter. Exogenous application of brassinazole (BRZ) and VIGS silencing experiments verified that the ICE-CBF cold response pathway could regulate the low-temperature-regulated protein CsCOR413. In summary, these findings elucidate that CsCOR413 expression is modulated not only by the classic ICE-CBF signaling pathway but also directly regulated by CsBES1-14. These findings outline the key components of the cold resistance network in tea plant and provide novel molecular targets for genetic improvement strategies in perennial crops.

Auxin accumulates in the Shoot Apical Meristem where the phyllotaxis inhibition potential exhibits local minima.

Flowering time is a critical trait in Chinese cabbage, particularly in stalk-type cultivars. In this study, we characterized two allelic early flowering mutants efm1 and efm2 of Chinese cabbage whose mutant characteristics were similar and insensitive to photoperiod, vernalization, and also GA3 treatments. Genetic analysis revealed that the early flowering trait was controlled by a single recessive nuclear gene. The causal gene, BrEPCR1, was identified via MutMap and KASP techniques, and its function was further validated by sequencing analysis of allelic mutants and transient transformation. BrEPCR1 was a homologue of Arabidopsis thaliana EPCR1, a polycomb-related protein involved in histone deacetylation and heterochromatin silencing. ChIP-qPCR revealed that H4K5ac levels decreased at BrFLC2/3 in the efm1 mutant. The lost part of BrEPCR1, the EPL domain, was necessary for the interaction between BrEPCR1 and BrMBD9. Brepcr1 had the application potential to promote the early maturity in stalk type of Chinese cabbage.

Metabolic engineering Corynebacterium glutamicum for efficient production of gastrodin.