The Plant Journal最新文献

N⁶-methyladenosine (m⁶A) modification occurs prevalently in eukaryotic mRNAs and is a key epitranscriptomic mechanism regulating plant development and stress responses. The m⁶A mark is interpreted by ‘readers’ that recognize and bind to m⁶A-modified RNAs. Recent studies highlight Evolutionarily Conserved C-terminal region (ECT) proteins as m⁶A readers in various plant species. However, the functions of many ECT proteins remain unknown. Therefore, this study aims to determine the role of ECT10 as an m⁶A reader and to evaluate its function in drought stress response in Arabidopsis. The electrophoretic mobility shift assay demonstrated that ECT10 specifically binds to m⁶A-modified RNAs but not to m⁵C-modified RNAs in vitro. The expression of ECT10 decreased markedly under drought stress conditions. The ect10 loss-of-function mutant exhibited reduced sensitivity to drought stress. Complementation lines expressing the native ECT10 in the ect10 mutant background restored the wild-type phenotype, while lines expressing the mutant mECT10, harboring substitutions at two critical amino acid residues, failed to rescue the phenotype. ECT10 regulated the expression of several m⁶A-modified positive or negative regulators of the drought stress response by modulating their stability through direct binding to these m⁶A-modified transcripts in planta. Collectively, these findings establish ECT10 as a novel m⁶A reader crucial for drought stress response by modulating mRNA stability.

Vegetable grafting is a horticultural technique employed to develop specialized plant varieties by effectively enhancing resistance to both biotic and abiotic stresses, as well as improving fruit quality and yield. However, these advantageous traits are generally non-heritable. The MSH1 gene induced heritable enhancement-through-grafting (HEG) effect on growth vigor, demonstrating promising application potential. In this study, we employed the msh1 mutant tomato as a rootstock to induce heritable superior traits and combined this approach with hybridization techniques to enhance tomato cultivars. Three Slmsh1 mutants were generated using CRISPR/Cas9 which exhibited a dwarf phenotype with whitened spots. By grafting several distinct inbred lines onto Slmsh1, we observed significant HEG, drought stress tolerance, and fruit quality. Under drought conditions, Slmsh1-grafted tomato seedlings exhibited increased biomass and enhanced drought tolerance through the regulation of antioxidant enzyme activities. Differential expression and methylation analyses of the graft progeny revealed that these heritable enhanced traits (HETs) are likely attributable to epigenetic modifications in the expression of ROS-scavenging- and hormone-related genes. Furthermore, to explore practical applications, we crossed inbred lines with HETs and evaluated the growth, yield, and fruit quality of the resulting hybrid combinations. The results indicated that these hybrid combinations improved fruit yield and quality, enhancing the total soluble solids, soluble sugar, and soluble protein content. These findings suggest that Slmsh1-grafted progenies enhanced plant biomass and drought resistance, while their hybrid combinations positively influenced root growth, yield, and fruit quality, providing new insights into the synergistic integration of genome editing and conventional breeding.

Low-temperature stress affects plant growth, and WRKY transcription factors alleviate such damage by regulating downstream genes. This study found that tomato SlWRKY39 significantly responds to low temperatures: its overexpression enhances seedling low-temperature tolerance by promoting ROS scavenging, while knockout exacerbates ROS accumulation and increases sensitivity to low temperatures. Transcriptome analysis indicated induction of glutathione metabolic pathway genes in slwrky39 plants under low-temperature stress. Y1H, EMSA, and Dual-LUC experiments confirmed that SlWRKY39 specifically binds to and activates the SlGSTU42 promoter; silencing SlGSTU42 attenuated the low-temperature tolerance conferred by SlWRKY39 overexpression, verifying that SlWRKY39 improves low-temperature tolerance via direct regulation of SlGSTU42. Additionally, SlZF61 interacts with SlWRKY39, enhancing its regulatory effect on SlGSTU42. SlZF61 overexpression strengthens low-temperature tolerance, while knockout increases sensitivity to low temperatures. In summary, under low-temperature stress, SlWRKY39 and SlZF61 are upregulated expression in tomato; SlWRKY39 binds to the SlGSTU42 promoter, and SlZF61 interacts with SlWRKY39 to form a protein complex, enhancing this binding. They synergistically activate SlGSTU42 transcription, thereby improving seedling low-temperature tolerance by scavenging ROS. This coordinated regulatory mechanism provides a new theoretical basis and practical insights for enhancing tomato low-temperature tolerance and ensuring stable production under low-temperature stress conditions.

Numerous studies have already demonstrated that cytokinin (CK) distribution plays a pivotal role in shaping plant morphology in response to environmental changes. However, the contribution of short-distance CK translocation to root mineral nutrition remains poorly understood, and the specific roles of CK transporters in root morphology are still unclear. Identifying the molecular identity of CK transporters is, therefore, essential for advancing our understanding of root plasticity, under varying soil fertility conditions and common nutritional deficiencies. In this study, we identified and characterised MtABCG40, a full-size ATP-binding cassette (ABC) transporter of the G subfamily in Medicago truncatula, as a CK transporter. MtABCG40 expression is root-specific, and it is induced both by nitrogen deficiency and CK treatment. We propose that MtABCG40 mediates the lateral translocation of CKs from the xylem to surrounding cells, giving rise to lateral organs, and thereby influencing root morphology, by suppressing the lateral root and nodule formation under nitrogen-limited conditions. Furthermore, MtABCG40 reduces apoplastic CK concentrations in the root meristematic zone, lowering the responsiveness of the root apical meristem to CKs. In summary, the activity of MtABCG40 indirectly influences CK perception and, consequently, modulates auxin-mediated cellular responses.

Peanut productivity and quality improvement rely on understanding the genetic factors influencing pod and seed size. This study aims to identify genetic factors and regulatory mechanisms influencing pod and seed size in peanuts. Herein, a genome-wide association study (GWAS) was conducted using 390 accessions from 15 peanut growing regions to analyze pod and seed traits across multiple planting seasons. A significant phenotypic variation was observed, with broad-sense heritability ranging from 53.6 to 85.4%. Strong correlations between pod and seed traits further suggest potential for co-selection in breeding efforts. A pleiotropic hotspot on chromosome B06 was strongly associated with six pod and seed traits. A peanut pod size regulator AhPDS1 (PODSIZE-1, Ahy_B06g085516) homolog of Arabidopsis thaliana YUCCA4 (AtYUC4, AT5G11320), involved in auxin biosynthesis, was selected as a candidate regulating pod and seed size. Quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) confirmed higher AhPDS1 expression in large pod as compared with the small pod genotypes. Subcellular localization showed AhPDS1 to be predominantly cytoplasmic, and GUS reporter assays indicated widespread expression in roots, stems, leaves, flowers, and pods, suggesting a broad functional role. Further overexpression of AhPDS1 in Arabidopsis and rice enhanced pod, seed, and grain sizes via the indole-3-pyruvic acid pathway in transgene lines. These findings highlight AhPDS1 as a potential target for peanut molecular breeding, offering opportunities to enhance pod size via auxin biosynthesis and support sustainable crop improvement.

As the last stage of leaf development, senescence is orchestrated by an intricate network of endogenous factors and external signals to ensure an efficient recycling of nutrients. Hydrogen sulfide (H₂S) serves as an important gaseous signaling molecule in plants, mediating a myriad of physiological processes like leaf senescence. However, the molecular mechanisms underlying H₂S accumulation and its regulation during leaf senescence in tobacco are still not fully elucidated. In this work, we demonstrate that NtWRKY75, a WRKY transcription factor in tobacco (Nicotiana tabacum), serves as a negative regulator of the expression of the key genes involved in H₂S biosynthesis (l-cysteine desulfhydrase, NtLCD1; d-cysteine desulfhydrase, NtDCD1), thereby accelerating dark-induced leaf senescence. The transcript levels of NtWRKY75 are progressively upregulated during both dark-induced and natural leaf senescence. Transgenic tobacco plants overexpressing NtWRKY75 show premature leaf senescence, while ntwrky75 mutants generated through CRISPR/Cas9 exhibit delayed leaf senescence. Further molecular and biochemical analyses reveal that senescence-associated NtWRKY75 binds to the promoters of NtDCD1 and NtOASA1, downregulating NtDCD1 expression while upregulating NtOASA1, thereby leading to decreased H₂S accumulation. NtWRKY75 also interacts with the promoters of multiple amino acid transporter genes, including NtAAP3, resulting in their upregulation and facilitating amino acid remobilization, which accelerates leaf senescence. Additionally, NtVQ47, a protein containing the VQ motif, physically interacts with NtWRKY75 in vivo and in vitro, thereby fine-tuning its transcriptional activity and influencing leaf senescence. In conclusion, our findings demonstrate that the regulatory network composed of NtVQ47, NtWRKY75, and H₂S plays a crucial role in precisely modulating leaf senescence, offering promising candidates and strategies for future crop improvement.

Grain size is a critical yield determinant and a complex quantitative trait in rice. The major quantitative trait locus GS2, which encodes the transcriptional regulator OsGRF4, has been characterized as a key controller of grain size and grain weight in rice. Building upon existing germplasm resources, exploring the upstream and downstream genes of known grain size regulators is an effective approach to gradually refine and expand the molecular regulatory network underlying grain size. Here, we report that a suppressor of the gain-of-function allele GS2^AA, SUG2, which encodes an importin β nuclear transport protein. Phenotypic characterization reveals that the sug2 GS2^AA mutant exhibits small grains by inhibiting cell expansion in the spikelet hull. Protein interaction analyses demonstrate that SUG2 physically interacts with GS2 both in vivo and in vitro, and the SUG2^A mutation reduces SUG2 expression levels and inhibits GS2 transcriptional activation activity, resulting in decreased GS2 expression levels and GS2 protein abundance in sug2 GS2^AA. Genetic analyses indicate that SUG2 and GS2 may be partially involved in a common pathway regulating grain size and weight in rice. These findings elucidate the grain size regulatory relationship between SUG2 and GS2 and provide novel insights into the precision breeding of yield optimization in rice.