Plant Cell Reports最新文献

Key message: The representative model in the TAIR database of the first and main rate-determining enzyme of the carotenoid pathway, phytoene synthase (PSY), corresponds to a computational prediction artifact.

Key message: The 'X4' accession of zoysiagrass demonstrated superior drought tolerance compared to other accessions. Integration analysis of transcriptomics and epigenomics revealed a positive correlation between ATAC-seq peak intensity and gene expression levels. Six motifs involved in regulating drought responses were identified, which are similar to the domains of the ERF and C2H2 transcription factor families. Heterologous expression of Zja11G000860 in yeast enhanced tolerance to drought stress, allowing robust growth even at high PEG6000 concentrations. Zoysiagrass is renowned for its drought tolerance and serves as an exceptional domestic turfgrass in China. However, the changes in chromatin accessibility during drought in zoysiagrass are not well understood. We conducted a preliminary evaluation of the phenotypic changes in drought tolerance for six zoysiagrass cultivars, taking into account their growth characteristics and physiological traits under drought conditions. Additionally, we utilized an integrated multi-omics strategy, encompassing RNA sequencing (RNA-seq), Assay for Transposase Accessible Chromatin using high-throughput sequencing (ATAC-seq), and reverse transcription quantitative PCR (RT-qPCR) verification experiments, to gain deeper understanding of the chromatin accessibility patterns linked to gene expression in response to drought stress in zoysiagrass. Preliminary analysis of the trends in relative water content and proline content suggested that the variety 'X4' exhibited superior drought tolerance compared to the other five accessions. The KEGG pathway enrichment analysis revealed that zoysiagrass responded to environmental stress by regulating stress response and antioxidant defense pathways. Notably, the expression levels of genes Zja03G031540 and Zja11G000860 were significantly increased in the 'X4' zoysiagrass genotype, which exhibited improved drought tolerance, compared to the 'X1' zoysiagrass genotype with reduced drought tolerance. This study suggested that 63 high-confidence genes are related to drought stress, including Zja03G031540 and Zja11G000860. Additionally, six motifs regulating drought responses were unearthed. Furthermore, the heterologous expression of Zja11G000860 in yeast enhanced tolerance to drought stress. The study discovered a positive correlation between ATAC-seq peak intensity and gene expression levels. The expression of high-confidence genes was linked to zoysiagrass resistance evaluation and phenotypic traits, implying that these genes are involved in responding to external drought stress. This study combined ATAC-seq and RNA-seq technologies for the first time to identify drought-related gene expression in zoysiagrass, elucidating the grass adaptation to environmental stress and the regulatory mechanisms underlying stress responses, and laying the groundwork for zoysiagrass improvement and breeding.

Key message: High transformation and gene editing efficiencies in sorghum-produced, transgene-free SDN1-edited plants exhibit precise mutations, reduced germination stimulants, and enhanced resistance to Striga infection. Sorghum (Sorghum bicolor L.) is a primary food staple grain for millions in Sub-Saharan Africa (SSA). It is mainly constrained by the parasitic weed Striga, which causes up to 100% yield losses and affects over 60% of cultivable farmlands and livelihoods. In this study, CRISPR/Cas9 technology is utilized to induce mutations in core strigolactone (SL) biosynthetic genes, i.e., CCD7, CCD8, MAX1, in addition to an uncharacterized gene (DUF) in the fine-mapped 400 kb lgs1 region in sorghum to develop durable Striga resistance. Two sorghum cultivars were delivered with the expression cassettes through immature embryo-based Agrobacterium-mediated transformation. Our study demonstrated transformation and gene editing efficiencies of ~ 70 and up to 17.5% (calculated based on the numuber of established plants), respectively, in two sorghum genotypes. Subsequent analysis of homozygous E₀ lines in the E₁ generation confirmed stable integration of mutations for all targeted genes. Loss-of-function mutations in the CCD7, CCD8, MAX1, and DUF genes led to a significant downregulation of the expression of associated genes in the SL biosynthetic pathway. The phenotypic analysis of edited lines revealed changes in phenotypic patterns compared to wild-type plants. Analysis of root exudates showed significant reductions in SL production in edited lines compared to wild-type plants. Striga infection experiments demonstrated delayed or reduced emergence rates of Striga in edited lines with lower SL production, highlighting the potential for genetically altering SL production to control Striga infestations. This study provides insights into the functional roles of CCD7, CCD8, MAX1, and DUF genes in sorghum towards reduced and/or altered SL production and improved resistance to Striga infestations.

Key message: A promoter, PRSEP7, was identified and confirmed to be specifically expressed in poplar roots. Poplar PRSEP7::CadWp transgenic lines showed high phytoremediation of Cd(II)-contaminated WPM and soil. Cadmium ions (Cd(II)) are heavy metals that are difficult for organisms to decompose in our natural environment. The generation of plants by genetic engineering with a high ability to phytoremediate Cd(II) from the soil is an ideal biological remediation strategy. Here, we identified and confirmed a promoter, PRSEP7, that is specifically expressed in poplar (Populus L.) roots. The promoter of PRSEP7 was then used to construct the poplar root expression vector 2301S-root. The CadW gene encoding a carbonic anhydrase (CA) was reported to play important roles in the phytoremediation of Cd(II) in microorganisms in a previous study. The sequence of CadW was optimized for plants, and the resulting gene CadWp also showed high activity for sequestration of Cd(II). CadWp was then introduced to 2301S-root to generate the PRSEP7::CadWp construct. This construct was used to transform poplar via Agrobacterium-mediated transformation. A number of stable transgenic poplar lines were generated, and two lines were randomly selected to test their ability to phytoremediate Cd(II). With several parameter measurements, the two transgenic lines showed high phytoremediation of Cd(II) under multiple growth conditions. Overall, we generated elite plant materials for the phytoremediation of Cd(II) in this study.

Key message: Transgenic soybean event CAL-16 expressing fusion Bt protein Cry1Ab-Vip3A was developed for conferring broad-spectrum resistance to lepidopteran pests Lepidopteran insect species are important soybean pests causing significant yield loss and quality degradation worldwide. Transgenic soybeans expressing crystal (Cry) insecticidal proteins have been utilized for insect pest management. However, the efficacy of currently adopted insect-resistant soybean is challenged by insect resistance evolution. Vegetative insecticidal proteins (Vips) are highly active against a broad spectrum of lepidopteran insects. They differ from Cry in modes of action, and show great potential for lepidopteran pest management. Here, we report the creation and characterization of a transgenic soybean event CAL-16 which expresses a fusion protein of Cry1Ab and Vip3A. CAL-16 is a single copy T-DNA insertion transgenic event highly resistant to a broad-spectrum of lepidopteran insects. Insect bioassays demonstrated that CAL-16 caused 100% mortality to neonates of Helicoverpa armigera, Spodoptera litura, Agrotis ipsilon, Spodoptera exigua and Spodoptera frugiperda. Field trial also demonstrated its excellent resistance to Leguminivora glycinivorella, a severe pest feeding on soybean seeds. The expression of the fusion protein was found to be constitutively high in CAL-16 throughout developmental stages, and highly stable over 12 generations. Moreover, there was no statistical difference in agronomic traits between CAL-16 and its non-transgenic recipient control plants in field trial. In conclusion, CAL-16 is an elite soybean event with high efficacy toward major lepidopteran pests. It is expected to be released for commercial cultivation in the near future in China as it has been deregulated in China in 2023.

Key message: Genome-wide identified 144 MYB family members in B. papyrifera. Integrated correlation analysis and target gene-binding motif prediction indicate that BpMYB135 is vital in regulating selenium metabolism. Selenium is an essential micronutrient for maintaining the health of humans and animals. Broussonetia papyrifera, a forage tree with high nutritional value, exhibits a remarkable ability to accumulate selenium. Although previous studies have preliminarily unfolded the molecular mechanisms underlying selenium accumulation, the roles of transcription factors in regulating selenium uptake and transformation remain poorly understood. This study used various strategies including bioinformatic, physiological, and molecular experiments to explore candidates regarding Se metabolism. Briefly, 144 MYB transcription factor family members were identified and classified into four types (R1, R2R3, R1R2R3, and R4), with phylogenetic analysis further dividing them into 58 subfamilies. The promoters of those BpMYBs contain numerous cis-acting elements associated with plant growth, development, and stress response. qRT-PCR assay confirmed 8 of 15 BpMYBs exhibit a remarkable correlation with selenium content at the threshold absolute value of 0.5. Additionally, foliar application of exogenous abscisic acid (ABA), methyl jasmonate (MeJA), and salicylic acid (SA) reveals different response patterns of BpMYBs. The subcellular localization assay simultaneously verifies that the candidate BpMYB135 functions within the nucleus. Overall, this funding highlights the potential regulatory mechanisms of selenium metabolism in B. papyrifera, providing a foundation for improving its forage value through genetic modification.

Key message: The JA and ICE-CBF-COR signaling pathways play important roles in the low-temperature response of Rosa persica, with RpMYC2 interacting with multiple transcription factors and positively regulating tolerance to low-temperature stress. Rosa persica is highly resilient to cold and drought, making it a valuable resource for breeding in the Rosa. However, the response mechanism of R. persica during the overwintering period remains unclear. This study examined root and stem tissues of R. persica over an eight-month natural open field overwintering period, measuring physiological indices of cold tolerance and investigating changes in cold tolerance across different overwintering stages. The values of physiological indicators of cold hardiness of R. persica roots and stems increased and then decreased. Osmoregulatory substances were the primary contributors to cold hardiness of R. persica roots, while antioxidant enzyme systems played a dominant role in cold hardiness of stems. Differential gene enrichment analyses revealed that oxidative reactions, the synthesis of various secondary metabolites, and hormone signaling pathways are crucial in establishing cold tolerance of R. persica at different overwintering stages. Weighted gene co-expression network and time-ordered gene co-expression network analyses identified the gene RpMYC2 as potentially key to cold tolerance in R. persica. Yeast two-hybrid discovery revealed that RpMYC2 interacts with multiple transcription factors to regulate cold stress resistance in R. persica. Based on the transcriptome, key genes involved in response to low temperature were identified in this study, providing the physiological and molecular insights for cold tolerance breeding of Rosa.

Key message: A total of 54 genes of membrane attack complex/perforin (MACPF) superfamily were identified in Saccharum complex and function divergence among SsaCAD-like genes were present in plant against stressors. The membrane attack complex/perforin (MACPF) superfamily belongs to pore-forming proteins involving in innate and adaptive immunity in eukaryotes. The constitutively activated cell death (CAD) proteins contained the MACPF domain participate in plant defense responses under adverse conditions. However, the characteristics and functions of CAD-like genes in sugarcane are still poorly understood. In this study, 54 CAD-like genes were identified in three genomes from Saccharum complex including two clones (Np-X and AP85-441) of Saccharum spontaneum and a clone (Yunnan2009-3) of Erianthus rufipilus. All CAD-like genes were categorized into five phylogenetic groups (I-V). Various cis-acting elements related to stress responses, such as phytohormone response elements, were found in promoter regions. Transcriptome and RT-qPCR analysis demonstrated these genes possessing diverse expression profiles. The SsaCAD1-like1 gene was upregulated in sugarcane cultivars after cold treatment and infection by Xanthomonas albilineans (Xa) causing leaf scald. Meanwhile, this gene was downregulated under drought and ABA treatments but was upregulated and then downregulated across time-points of SA treatment. The SsaCAD4-like1 gene was downregulated under five abiotic stressors. Expression levels of two alleles (SsaCAD2-like1/2) were significantly decreased under all abiotic stressors except for salinity treatment. Similar expression patterns of three alleles (SsaCAD3-like1/2/4) were found under abiotic stress. The SsaCAD1-like1 exhibited a negative role but SsaCAD3-like2/4 acted as positive roles in transgenic Arabidopsis lines against bacterial pathogen infection. Our results provide novel gene resources for developing disease-resistant cultivars in sugarcane.

Key message: Our findings suggest that the phytohormone salicylic acid, stimulated by Bacillus megaterium JPR68, plays a role in mitigating collar rot disease of Bhut Jolokia (Capsicum chinense Jacq.) Salicylic acid (SA) is a phytohormone that stimulates the plants immune response against various diseases. However, its function as a signaling molecule, particularly in relation to systemic acquired resistance (SAR) and induced systemic resistance (ISR), is still unclear. In this study, Bacillus megaterium JPR68 (BmJPR68) enhances the ISR of Capsicum chinense Jacq., resulting in elevated levels of SA within the plants. SA effectively inhibited the mycelial growth of Rhizoctonia solani and significantly reduced the necrosis, chlorosis, and collar rot in plants. The in vitro investigation revealed that the mycelial growth declined with increasing concentrations of SA and was completely inhibited at a concentration of 15 mM. The pathogenicity assay showed that leaves and fruits treated with SA impeded hyphal development and significantly retarded the growth of R. solani. In split root techniques, more SA was accumulated in the root tissues at the bacterized site compared to the non-bacterized side, although this accumulation reduced after 45 days. Additionally, the production of reactive oxygen species (ROS) was significantly diminished in plants treated with BmJPR68. SA production was assessed in both BmJPR68 and induced plants, indicating that the bacterial strain produced more SA compared to the induced plants. Fourier-transform infrared (FT-IR) analysis confirmed the presence of functional groups like O-H, N-H, S = O, C = C, C-N, and carboxylic/amine. The isoform of pathogenesis-related (PR) proteins was detected in the induced plants. This study provided valuable insights into SA induction using BmJPR68 to manage fungal disease in Capsicum chinense Jacq. during induced systemic resistance.