Transgenic soybean (Glycine max) plants expressing mutant potyviral coat proteins that disrupt virion assembly exhibited non-strain-specific resistance against soybean mosaic virus.
Transgenic soybean (Glycine max) plants expressing mutant potyviral coat proteins that disrupt virion assembly exhibited non-strain-specific resistance against soybean mosaic virus.
A newly developed RNA-based adenine and cytosine base editing system achieves targeted and efficient A-to-G and C-to-T conversions in lettuce. This DNA-free base editing method has potential uses in crop breeding and biotechnology.
Diatoms rely on fucoxanthin chlorophyll a/c-binding proteins (FCPs) for light harvesting and energy quenching under marine environments. Here we report two cryo-electron microscopic structures of photosystem I (PSI) with either 13 or five fucoxanthin chlorophyll a/c-binding protein Is (FCPIs) at 2.78 and 3.20 Å resolutions from Thalassiosira pseudonana grown under high light (HL) conditions. Among them, five FCPIs are stably associated with the PSI core, these include Lhcr3, RedCAP, Lhcq8, Lhcf10, and FCP3. The eight additional Lhcr-type FCPIs are loosely associated with the PSI core and detached under the present purification conditions. The pigments of this centric diatom showed a higher proportion of chlorophylls a, diadinoxanthins, and diatoxanthins; some of the chlorophyll as and diadinoxanthins occupy the locations of fucoxanthins found in the huge PSI-FCPI from another centric diatom Chaetoceros gracilis grown under low-light conditions. These additional chlorophyll as may form more energy transfer pathways and additional diadinoxanthins may form more energy dissipation sites relying on the diadinoxanthin-diatoxanthin cycle. These results reveal the assembly mechanism of FCPIs and corresponding light-adaptive strategies of T. pseudonana PSI-FCPI, as well as the convergent evolution of the diatom PSI-FCPI structures.
Plant growth is determined by the production of cells and initiation of new organs. Exploring genes that control cell number and cell size is of great significance for understanding plant growth regulation. In this study, we characterized two wheat mutants, ah and dl, with abnormal growth. The ah mutant is a naturally occurring variant characterized by severe dwarfism, increased tiller number, and reduced grain length, while the dl mutant is derived from an ethyl methane sulfonate (EMS)-mutagenized population and exhibits smaller grain size and slightly reduced plant height. Cytological analyses revealed abnormal cell number, cell morphology and arrangement in the stems and leaves of the ah mutant, along with reduced cell length in the grains of the dl mutant. Map-based cloning identified that both mutants carry mutations in the same gene TavWA1-7D, which encodes a protein with a von Willebrand factor A (vWA) domain. The ah mutant harbors a 174-bp insertion in the 1,402-bp coding sequence (CDS) of TavWA1-7D, causing premature termination of protein translation, while the dl mutant contains a Glu420Lys substitution. Mimicking the TavWA1-7Dah through clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated nuclease 9-mediated genome editing leads to a severe dwarfism phenotype. The C-terminus of the protein is crucial for its correct subcellular localization and interaction, supporting its critical role for TavWA1-7D function. Proteomic analysis showed that the dwarf phenotype of the ah mutant is associated with impaired photosynthesis, ribosome function, and nucleosome formation. Additionally, TavWA1-7D interacts with an E3 ligase, TaVIP1-3B, the expression levels of which are elevated in both mutants. Overexpression and knockout studies of TaVIP1-3B demonstrated its negative regulatory role in cell length and grain size. Together, our findings suggest that TavWA1-7D plays a vital role in regulating wheat growth and yield-related traits, with the dl mutant's short grain phenotype being associated with TaVIP1-3B expression levels.
Firs (Abies spp.) are keystone components of the boreal and temperate dark-coniferous forests and this genus harbors a number of relict taxa. Wei et al. (pages 2664-2682) reconstructed a transcriptomebased phylogeny and revealed the spatiotemporal evolution of global firs based on complete species sampling. Evolutionary and ecological analyses indicate that all extant firs underwent diversification in the Late Cenozoic, with the species richness distribution driven primarily by elevation and precipitation of the coldest quarter. Some morphological traits linked to elevational variation and cold tolerance may have contributed to the diversification of global firs. This work may inform forest management and species conservation in a warming world. The cover shows the dark blue cones of an alpine fir (Abies georgei var. smithii).
Besides playing a crucial role in plant immunity via the nonexpressor of pathogenesis-related (NPR) proteins, increasing evidence shows that salicylic acid (SA) can also regulate plant root growth. However, the transcriptional regulatory network controlling this SA response in plant roots is still unclear. Here, we found that NPR1 and WRKY45, the central regulators of SA response in rice leaves, control only a reduced sector of the root SA signaling network. We demonstrated that SA attenuates root growth via a novel NPR1/WRKY45-independent pathway. Furthermore, using regulatory network analysis and mutant characterization, we identified a set of new NPR1/WRKY45-independent regulators that conservedly modulate the root development and root-associated microbiota composition in both Oryza sativa (monocot) and Arabidopsis thaliana (dicot) in response to SA. Our results established the SA signaling as a central element regulating plant root functions under ecologically relevant conditions. These results provide new insights to understand how regulatory networks control plant responses to abiotic and biotic stresses.
Phosphorus (P) is an essential macronutrient for plant growth and development. Vacuoles play a crucial role in inorganic phosphate (Pi) storage and remobilization in plants. However, the physiological function of vacuolar phosphate efflux transporters in plant Pi remobilization remains obscure. Here, we identified three ZmVPE genes (ZmVPE1, ZmVPE2a, ZmVPE2b) by combining them with transcriptome and quantitative real-time polymerase chain reaction (PCR) analyses, showing a relatively higher expression in older leaves than in younger leaves in maize. Moreover, the expression of the ZmVPEs was triggered by Pi deficiency and abscisic acid. ZmVPEs were localized to the vacuolar membrane and responsible for vacuolar Pi efflux. Compared with the wild-type, Pi remobilization from older to younger leaves was enhanced in ZmVPE-overexpression lines. zmvpe2a mutants displayed an increase in the total P and Pi concentrations in older leaves, but a decrease in younger leaves. In rice, Pi remobilization was impaired in the osvpe1osvpe2 double mutant and enhanced in OsVPE-overexpression plants, suggesting conserved functions of VPEs in modulating Pi homeostasis and remobilization in crop plants. Taken together, our findings revealed a novel mechanism underlying Pi remobilization from older to younger leaves mediated by plant vacuolar Pi efflux transporters, facilitating the development of Pi-efficient crop plants.
Glycosylation, a prevalent post-translational modification in eukaryotic secreted and membrane-associated proteins, plays a pivotal role in diverse physiological and pathological processes. Although UDP-N-acetylglucosamine (UDP-GlcNAc) is essential for this modification, the specific glycosylation mechanisms during plant leaf senescence and defense responses remain poorly understood. In our research, we identified a novel rice mutant named rbb1 (resistance to blast and bacterial blight1), exhibiting broad-spectrum disease resistance. This mutant phenotype results from a loss-of-function mutation in the gene encoding glucosamine-6-phosphate acetyltransferase, an important enzyme in D-glucosamine 6-phosphate acetylation. The rbb1 mutant demonstrates enhanced defense responses, evident in increased resistance to rice blast and bacterial blight, along with the upregulation of defense-response genes. Various biochemical markers indicate an activated defense mechanism in the rbb1 mutant, such as elevated levels of reactive oxygen species and malondialdehyde, reduced enzyme activity and UDP-GlcNAc content, and decreased expression of N-glycan and O-glycan modifying proteins. Moreover, proteome analysis of N-glycosylation modifications reveals alterations in the N-glycosylation of several disease-resistance-related proteins, with a significant reduction in Prx4 and Prx13 in rbb1-1. Additionally, the knockout of Prx4 or Prx13 also enhances resistance to Xanthomonas oryzae pv. oryzae (Xoo) and Magnaporthe oryzae (M. oryzae). This study uncovers a novel mechanism of defense response in rice, suggesting potential targets for the development of disease-resistant varieties.
Fruit taste quality is greatly influenced by the content of soluble sugars, which are predominantly stored in the vacuolar lumen. However, the accumulation and regulation mechanisms of sugars in most fruits remain unclear. Recently, we established the citrus fruit vacuole proteome and discovered the major transporters localized in the vacuole membrane. Here, we demonstrated that the expression of tonoplast sugar transporter 2 (CsTST2) is closely associated with sugar accumulation during sweet orange (Citrus sinensis) ripening. It was further demonstrated that CsTST2 had the function of transporting hexose and sucrose into the vacuole. Overexpression of CsTST2 resulted in an elevation of sugar content in citrus juice sac, calli, and tomato fruit, whereas the downregulation of its expression led to the reduction in sugar levels. CsTST2 was identified as interacting with CsCIPK23, which binds to the upstream calcium signal sensor protein CsCBL1. The phosphorylation of the three serine residues (Ser277, Ser337, and Ser354) in the loop region of CsTST2 by CsCIPK23 is crucial for maintaining the sugar transport activity of CsTST2. Additionally, the expression of CsCIPK23 is positively correlated with sugar content. Genetic evidence further confirmed that calcium and CsCIPK23-mediated increase in sugar accumulation depends on CsTST2 and its phosphorylation level. These findings not only unveil the functional mechanism of CsTST2 in sugar accumulation, but also explore a vital calcium signal regulation module of CsCBL1/CIPK23 for citrus sweetness quality.
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