生命科学最新文献

The glutamate receptor (GLR) serves as a ligand-gated ion channel that plays a vital role in plant growth, development, and stress response. Nevertheless, research on GLRs in cotton is still very limited. The present study conducted a comprehensive analysis of GLRs gene family in cotton. In total, 41 members of the GLR family were identified in cotton unveiling distinct subgroups in comparison to Arabidopsis. Among these members, the third subgroup highlights its pivotal role in cotton's defense against insect infestation. Furthermore, the CRISPR/Cas9 system was utilized to create a mutant library of GLR members, which consisted of a total of 135 independent mutant lines, resulting in the production of novel cotton materials with valuable breeding potential for pest control. Further, this study elucidates the influence of GhGLR3.4 on jasmonic acid (JA) pathway signal transduction and demonstrated its participation in the influx of intracellular Ca²⁺, which regulates "calcium transients" following stimulation, thereby influencing multiple intracellular reactions. The study also found that GhGLR3.4 influences the synthesis of the JA pathway and actively partakes in long-distance signal transmission among plants, facilitating the transfer of defense signals to neighbor leaves and thereby triggering systemic defense. Consequently, this research advances our knowledge of plants' comprehensive defense mechanism against insect pest infestation.

Cold stress affects the growth, development, and yield of asparagus bean (Vigna unguiculata subsp. sesquipedalis). Mediator (MED) complex subunits regulate the cold tolerance of asparagus bean, but the underlying regulatory mechanisms remain unclear. Here, VunMED2 positively responds to cold stress of asparagus beans. Under cold acclimation and freezing treatment, the survival rate, ROS scavenging activity, and expression levels of VunMED2 were increased in VunMED2 transgenic plants. Natural variation in the promoter of VunMED2 in two different cold-tolerant asparagus beans was observed. Under cold stress, the expression of the GUS reporter gene was higher in cold-tolerant plants than in cold-sensitive plants, and the expression of the GUS reporter gene was tissue-specific. VunHY5 positively influenced the expression of VunMED2 by binding to the E-box motif, and the transcriptional activation of the promoter was stronger in the cold-tolerant variety than in cold-sensitive plants. VunHY5 overexpression improved plant freezing resistance by increasing the antioxidant capacity and expression of dehydrin genes. VunHY5 and VunMED2 play a synergistic role in binding to the G-box/ABRE motif and transcriptionally activating the expression of VunERD14. VunERD14 complemented the med2 mutant, which could positively respond to plant freezing resistance by reducing membrane lipid peroxidation and improving the antioxidant capacity. Therefore, the VunHY5-VunERD14 module and the VunHY5-VunMED2-VunERD14 positive cascade effect are involved in the cold signal transduction in asparagus bean. Our findings have implications for the breeding of asparagus bean varieties with improved cold tolerance.

Individual effects of elevated ozone (O₃) and warming on wheat (Triticum aestivum L.) are well documented, their combined effects remain poorly understood. In the present study, we investigated the combined impacts of elevated O₃ (1.5× ambient O₃) and rising canopy temperature (+2°C) on the photosynthesis of wheat leaves in an open-air field experiment. We found that O₃-induced oxidative stress reduced the biochemical capacity and inhibited leaf photosynthesis at the end of the grain-filling stage. Night-time warming (NW) increased leaf photosynthesis during the vegetative stage, but whole-day warming (WW) did not. Both WW and NW accelerated wheat development and decreased photosynthesis at the end of the reproductive stage. Neither elevated O₃ nor warming stimulated antioxidant enzymes. Significant interaction between O₃ and WW indicated that WW mitigated the adverse effect of O₃ on leaf photosynthesis. Compared to NW, WW significantly increased daytime canopy temperature and canopy-to-air vapour pressure deficit across O₃ treatments. Decreases in leaf water content and increases in grain oxygen isotope discrimination under warming suggested a link of WW-induced protection against O₃ stress in photosynthesis with declines in stomatal O₃ uptake rather than increases in the antioxidant capacity. Our results indicate the need to consider the warming-induced mitigation of O₃ stress on leaf photosynthesis when predicting the effects of elevated O₃ on crop growth under warmer climate in the future.

Toxicodendron species are economically and medicinally important trees because of their rich sources of natural products. We present three chromosome-level genome assemblies of Toxicodendron vernicifluum 'Dali', Toxicodendron succedaneum 'Vietnam', and T. succedaneum 'Japan', which display diverse production capacities of specialized metabolites. Genome synteny and structural variation analyses revealed large genomic differences between the two species (T. vernicifluum and T. succedaneum) but fewer differences between the two cultivars within the species. Despite no occurrence of recent whole-genome duplications, Toxicodendron showed evidence of local duplications. The genomic modules with high expression of genes encoding metabolic flux regulators and chalcone synthase-like enzymes were identified via multiomics analyses, which may be responsible for the greater urushiol accumulation in T. vernicifluum 'Dali' than in other Toxicodendron species. In addition, our analyses revealed the regulatory patterns of lipid metabolism in T. succedaneum 'Japan', which differ from those of other Toxicodendron species and may contribute to its high lipid accumulation. Furthermore, we identified the key regulatory elements of lipid metabolism at each developmental stage, which could aid in molecular breeding to improve the production of urushiol and lipids in Toxicodendron species. In summary, this study provides new insights into the genomic underpinnings of the evolution and diversity of specialized metabolic pathways in three Toxicodendron cultivars through multiomics studies.

Fruit morphogenesis is determined by the coordination of cell division and expansion, which are fundamental processes required for the development of all plant organs. Here, we show that the regulation of TEOSINTE BRANCHED1/CYCLOIDEA/PCF (TCP) LANCEOLATE (TCP2/LA) by miR319 is crucial for tomato fruit morphology. The loss of miR319 regulation in the semi-dominant La mutant led to a premature SlTCP2/LA expression during gynoecium patterning, which results in modified cell division during carpel development. As a consequence, La mutants exhibited elongated ovary and fruit shape, and a reduced number of ovules and seeds. Elongated fruit shape in La may be partially due to the SlTCP2/LA-mediated repression of OVATE activity in young floral buds. Further analysis showed that the de-repression of SlTCP2/LA decreases auxin responses in young floral buds by directly repressing SlYUCCA4 expression, but SlTCP2/LA also acts in parallel with ENTIRE (E) to orchestrate fruit morphology and seed production. Our study defines a novel miRNA-based molecular link between the domestication-associated OVATE gene and auxin responses. Given the striking variation in fruit morphology among members of the Solanaceae family, fine-tuning regulation of gene expression by miRNA coupled with modulation of auxin dynamics may be a common driver in the evolution of fruit shape diversity.

Non-coding RNAs play crucial roles in plant responses to viral stresses. However, their molecular mechanisms in tea leaf spot responses remain unclear. In this study, using Camellia sinensis, we identified lncRNA81246 as a long non-coding RNA that localizes to both the nucleus and cytoplasm. It functions as a competitive endogenous RNA, thereby disrupting CsNAC1 (encoding NAC domain-containing protein 1) degradation mediated by miR164d. Silencing lncRNA81246 increased the resistance of tea plants to presistanceathogens, whereas transient lncRNA81246-overexpression plants showed decreased resistance to pathogens. Co-expression assays in Nicotiana benthamiana revealed that lncRNA81246 affects the miR164d-CsNAC1 regulatory module. Transient miR164d-overexpression and silencing assays demonstrated its positive regulation of tea plant resistance. Specifically, silencing its target, CsNAC1,enhanced disease resistance, whereas transient overexpression reduced plant resistance. Yeast one-hybrid, dual-luciferase, and RT-qPCR assay results suggested that CsNAC1 alters the expression of CsEXLB1, whereas AsODN and tobacco transient overexpression assays showed that CsEXLB1 negatively regulated tea plant resistance. Thus, our research demonstrated that lncRNA81246 acts as a mediator to interfere with the miR164d-CsNAC1 regulatory module involved in the disease resistance of tea plants.

Salivary proteins secreted by phytophagous insects play pivotal roles in plant-insect interactions. A salivary protein RpSP27, from the stinkbug Riptortus pedestris, a devastating pest on soybean, was selected for studying due to its ability to induce cell death and activate immune responses in plants. RpSP27 localized to the endoplasmic reticulum and triggered reactive oxygen species burst. Virus-induced gene silencing assays showed RAR1 plays an essential role in RpSP27-induced cell death in Nicotiana benthamiana. Expression analyses revealed that RpSP27 is predominantly expressed in R. pedestris salivary glands. RNA interference-mediated silencing of RpSP27 in R. pedestris significantly reduced insect survival rates and altered feeding behavior by decreasing the formation of salivary sheaths on soybeans and reducing probing and feeding duration. Furthermore, the silencing of RpSP27 in R. pedestris mitigated the staygreen syndrome in soybeans, characterized by delayed senescence and pod abnormalities. This study elucidated the role of RpSP27 in the interaction between R. pedestris and soybean, presenting a potential target for pest management strategies to protect soybean crops from the detrimental effects of R. pedestris feeding.

Plant roots are essential for water and nutrient uptake, as well as resistance to abiotic stresses. While measuring root systems under field conditions is labor-intensive, most quantitative trait loci (QTLs) related to root traits have been detected under artificial conditions. However, QTLs identified under artificial conditions may not always manifest the expected effects that are observed under field conditions. To address this issue, we developed RSApaddy3D, a rapid phenotyping method for rice root systems, using X-ray computed tomography (CT) volumes of soil blocks collected from paddies. RSApaddy3D employs 2-dimensional kernel filters tailored to extract disk-shaped fragments from the CT volumes. Tubular root fragments are expected to exhibit disk-shaped cross-sections along the x-, y-, or z-axes. By applying these filters along all three axes and integrating the results, 3-dimensional root fragments can be accurately extracted. Furthermore, vectorizing the root system enables geometrical removal of the roots of neighboring individuals. We conducted a genome-wide association study (GWAS) of root diameter, number, and growth angle in 133 Japanese rice varieties and detected three QTLs (qNCR1, qNCR2, and qRGA1) that were associated with each trait. This process was completed within 10 person-days from soil monolith collection in the paddy to the GWAS. Without RSApaddy3D, roots would need to be washed from the soil monolith and measured, which is estimated to require >500 person-days. Therefore, RSApaddy3D was approximately 50× more labor-saving. In summary, we have demonstrated that RSApaddy3D is an efficient method for phenotyping rice root systems under field conditions.

Mexican wild diploid potato species are reproductively isolated from A-genome species, including cultivated potatoes; thus, their genomic relationships remain unknown. Solanum stoloniferum Schlechtd. et Bché. (2n = 4x = 48, AABB) is a Mexican allotetraploid species frequently used in potato breeding. We constructed a chromosome-scale assembly of the S. stoloniferum genome using PacBio long-read sequencing and Hi-C scaffolding technologies. The final assembly consisted of 1742 Mb, among which 745 Mb and 713 Mb were anchored to the 12 A-genome and 12 B-genome chromosomes, respectively. Using the RNA-seq datasets, we detected 20 994 and 19 450 genes in the A and B genomes, respectively. Among these genes, 5138 and 3594 were specific to the A and B genomes, respectively, and 15 856 were homoeologous, of which 18.6-25.4% were biasedly expressed. Structural variations such as large pericentromeric inversions were frequently found between the A- and B-genome chromosomes. A comparison of the gene sequences from 38 diverse genomes of the related Solanum species revealed that the S. stoloniferum B genome and Mexican diploid species, with the exception of S. verrucosum, were monophyletically distinct from the S. stoloniferum A genome and the other A-genome species, indicating that the Mexican diploid species share the B genome. The content and divergence of transposable elements (TEs) revealed recent bursts and transpositions of TEs after polyploidization. Thus, the S. stoloniferum genome has undergone dynamic structural differentiation and TE mobilization and reorganization to stabilize the genomic imbalance. This study provides new insights into polyploid evolution and the efficient use of allotetraploid species in potato breeding.

Salinity poses a significant challenge to plant growth and crop productivity by adversely affecting crucial processes, including photosynthesis. Efforts to enhance abiotic stress tolerance in crops have been hindered by the trade-off effect, where increased stress resistance is accompanied by growth reduction. In this study, we identified and characterized a plastocyanin gene (PaPC) from the Antarctic moss Polytrichastrum alpinum, which enhanced photosynthesis and salt stress tolerance in Arabidopsis thaliana without compromising growth. While there were no differences in growth and salt tolerance between the wild type and Arabidopsis plastocyanin genes (AtPC1 and AtPC2)-overexpressing plants, PaPC-overexpressing plants demonstrated superior photosynthetic efficiency, increased biomass, and enhanced salt tolerance. Similarly, PaPC-overexpressing rice plants exhibited improved yield potential and photosynthetic efficiency under both normal and salt stress conditions. Key amino acid residues in PaPC responsible for this enhanced functionality were identified, and their substitution into AtPC2 conferred improved photosynthetic performance and stress tolerance in Arabidopsis, tobacco, and tomato. These findings not only highlight the potential of extremophiles as valuable genetic resources but also suggest a photosynthesis-based strategy for developing stress-resilient crops without a growth penalty.