The Plant Journal最新文献

In plants, ABF (ABA-responsive element binding factor)/AREB (ABA-responsive element binding) proteins regulate processes such as abiotic stress response, pathogen defense, and seed germination. However, the specific function and regulatory networks of ABF/AREB transcription factors during fruit ripening remain largely unknown. In this study, we found that the expression level of SlABF4 is abundant in tomato fruits and gradually decreases during the ripening process. Functional analysis confirmed that SlABF4 was localized in the cell nucleus and responded to ABA treatment. To further investigate the function of SlABF4 in fruit ripening, we generated overexpressing SlABF4 lines and CRISPR/Cas9-slabf4 knockout mutants. Compared with wild type (WT), the onset of fruit ripening in OE-SlABF4 lines was delayed and ethylene production reduced, while the slabf4-deficient mutants showed accelerated fruit ripening and increased ethylene release. Meanwhile, transcriptomic and qRT-PCR analyses indicated that the expression levels of several fruit ripening-related transcriptional factors and ethylene-associated genes were downregulated in OE-SlABF4 lines and upregulated in CR-slabf4 mutants. Importantly, yeast one-hybrid (Y1H), dual-luciferase reporter assays and electrophoretic mobility shift assays (EMSA) demonstrated that SlABF4 directly binds to the promoters of ethylene biosynthesis genes (SlACS2 and SlACS12) and represses their expression. Moreover, we found that SlABF4 can physically interact with two key ripening-related transcription factors (SlFUL1 and SlMADS1) to regulate tomato fruit ripening in vivo and in vitro, while SlABF4 inhibited the expression of SlACS2 to modulate ethylene biosynthesis. Together, these findings expand our insights into the negative regulatory role and molecular mechanism of SlABF4 in the fruit ripening process, which will provide support for precise breeding designed to mediate fruit ripening in tomato.

Watershield (Brasenia schreberi), belonging to Cabombaceae within the order Nymphaeales, represents one of the early-diverged angiosperm lineages. This perennial floating leaf freshwater aquatic plant features submerged juvenile leaves enveloped in a thick layer of transparent gelatinous mucilage, aiding in its resistance to aquatic stress. However, the evolutionary history of the mechanisms underlying its specific phenotype remains unclear. In this study, we present the telomere-to-telomere level genome of B. schreberi, unveiling that it underwent two rounds of whole-genome duplications (WGDs) and a recent whole-genome triplication, with the most ancient WGD being shared by Nymphaeaceae. WGD and dispersed duplication significantly contributed to the expansion of gene families, which are primarily associated with environmental adaptation. Additionally, we discovered that mature leaves primarily conduct photosynthesis and may transport nutrients to underwater juvenile leaves for polysaccharide synthesis. We also identified an ancestral broad expression pattern of ABC genes, and the similar expression of anthocyanin biosynthesis genes across all flower organs resulted in entirely purple flowers. Our findings deepen the understanding of the evolution of this specific aquatic plant phenotypes.

Drought is a major abiotic stress that severely constrains plant growth, development, and crop productivity. Identifying key drought-tolerance genes and deciphering their regulatory mechanisms are critical for enhancing crop resilience. The 14–3-3 proteins, a family of phosphopeptide-binding proteins, play pivotal roles in diverse signaling pathways, thereby influencing metabolism, development, and stress responses. However, their detailed mechanism in mediating drought tolerance in wheat (Triticum aestivum L.) remains largely elusive. In this study, we demonstrate that TaGF14b, a 14–3-3 family member in wheat, functions as a positive regulator of drought stress tolerance. Mechanistically, TaGF14b enhances abscisic acid (ABA) responses by interacting with the ABA-responsive element binding factor TaABF2, thereby amplifying the transactivation activity of downstream drought-responsive genes. Metabolomic profiling revealed that overexpression of TaGF14b mitigates drought-induced metabolic perturbations in wheat. Furthermore, we identified a novel regulatory mechanism wherein TaGF14b interacts with sucrose phosphate synthase TaSPS2, modulating its enzymatic activity to alleviate the perturbations in sugar metabolism under stress conditions. Intriguingly, TaSPS2 weakens the TaGF14b-TaABF2 interaction, thereby fine-tuning the transcriptional activation of ABA-responsive genes and preventing overactivation of the ABA signaling pathway. Our findings uncover a dual role of TaGF14b in coordinating drought tolerance through ABA-dependent gene regulation and the maintenance of sugar metabolism, providing novel insights into strategies for improving drought tolerance in wheat. Through integrated multi-omics and biochemical analyses, we demonstrate the significance of TaGF14b in maintaining metabolic homeostasis and mediating drought stress response, thereby highlighting its potential as a novel target for improving drought tolerance in wheat.

The recretohalophyte Limonium bicolor produces salt glands on its leaf surface and can thrive in saline soils. YABBY (YAB) family transcription factors participate in plant development and stress responses; our previous single-cell transcriptome data revealed high expression of LbYAB1 (Lb2G09016) in salt gland subclusters. Here, we confirmed the LbYAB1 expression in salt glands and leaf primordia using RNA in situ hybridization and promoter-driven GUS histological staining; moreover, LbYAB1 expression was induced under 6-benzylaminopurine treatment. We explored LbYAB1 function by generating overexpression and knockdown plants in L. bicolor. Compared with the wild-type, LbYAB1-overexpressing lines showed suppressed salt gland development, diminished salt secretion, and lower salinity tolerance; LbYAB1 knockdown plants displayed the opposite phenotypes, demonstrating that LbYAB1 is a negative regulator of salt gland development. LbYAB1 conferred greater salinity sensitivity in L. bicolor and in Arabidopsis thaliana when overexpressed. Multiple assays (a yeast two-hybrid, split-luciferase complementation and GST pull-down) supported the interaction of LbYAB1 with LbKNAT7 (Homeobox protein knotted-1-like 7), recently shown to inhibit transcription of LbSAD2, a positive regulator of salt gland development and salt tolerance. The LbYAB1–LbKNAT7 interaction enhanced the transcriptional repression of LbSAD2, thus regulating salt gland development. Our work places LbYAB1 upstream of LbSAD2 in salt gland development, providing insights into salinity tolerance genetics and paving the way for engineering salt-resistant crops, even in species lacking salt glands.

The declining costs of DNA sequencing have expanded genomic data, crucial for understanding plant abiotic stress responses and crop improvement. However, accurate gene annotation remains challenging. To address this limitation, we propose the PASRGA, a deep learning approach that leverages transfer learning and contrastive learning to annotate genes related to drought, salt, cold, and UV resistance. PASRGA achieves high F1-scores, area under the receiver operating characteristic (AUROC), area under the precision-recall curve (AUPRC), and Matthews correlation coefficient (MCC) in annotating stress resistance genes, significantly outperforming the general protein annotation model CLEAN, the plant phosphatase gene annotation model PF-NET, the top-ranked model in the CAFA5 challenge NetGO 4.0, and four traditional machine learning methods. Its effectiveness was further validated with a salt stress treatment experiment in Eutrema salsugineum. To facilitate crop breeding practices, we utilized PASRGA to annotate the genomes of 17 major crops. To improve accessibility and utility, we incorporated both manually curated and PASRGA-predicted gene data, together with the PASRGA tool, into the PlantASRG database (https://bioinfor.nefu.edu.cn/PlantASRG/). This comprehensive resource aims to support crop breeding initiatives and ensure food security.

Phytosterols, natural active components widely distributed in plants, commonly include β-sitosterol, stigmasterol, and campesterol. However, identifying their synthesis intermediates can be challenging because access to corresponding commercial standard compounds is not always possible. To overcome these limitations, we synthesized phytosterol intermediates by co-infecting Nicotiana benthamiana with verified phytosterol synthases and identified them via gas chromatography–mass spectrometry analysis. Then, we mixed the identified intermediates, re-analyzed them by GC–MS to get a customized standard mixture, and established the corresponding standard spectrum library and characteristic ion database. To prove the usability of this standard mixture, we analyzed sterol intermediate types and contents in OsSMO2-1 and OsSMO2-2 rice mutants with this tool. Using the standard mixture, we analyzed sterolomics in wild-type rice buds at different germination days. As buds grew, detectable sterol intermediates decreased; only campesterol, sitosterol, and stigmasterol were found at the 9-day-old bud. When we compared mutants (ossmo2-1/ossmo2-2) with the wild type, we noted an obvious peak of 24-ethylidenelophenol accumulation in the ossmo2-1 mutant, indicating non-equivalent functions of OsSMO2-1 and OsSMO2-2 in sterol synthesis. OsSMO2-1 is more crucial for stigmasterol and sitosterol synthesis. This validates the standard mixture's utility.

Enhancing rice photosynthesis is essential for increasing yield, yet the specific leaf morphological characteristics associated with high photosynthetic efficiency remain unclear. This study aims to investigate how reducing leaf width (LW) influences photosynthetic rate (A) and water-use efficiency (iWUE) in rice. Pot experiments were performed using 14 cultivated rice genotypes exhibiting considerable LW variations and genetically modified rice lines carrying the NARROW LEAF 1 (NAL1) gene. We observed a significant negative correlation between LW and A among the 14 cultivated rice varieties. Simultaneously, a 48.2% reduction in the LW of NAL1-K was accompanied by a 49.9% significant increase in A. Narrower leaves increased leaf hydraulic conductance and stomatal density, thereby synergistically augmenting stomatal conductance (g_s). Furthermore, increased stomatal density enhances mesophyll conductance (g_m) by facilitating airspace formation and less resistance to CO₂ transfer. Reduced LW also increased leaf nitrogen content and enhanced the maximum carboxylation rate of RuBisCO (V_cmax). Although reduced LW synergistically increased g_s, g_m, V_cmax, and ultimately A, it did not concurrently achieve a coordinated improvement in iWUE. Our findings provide valuable insights into the physiological mechanisms underlying photosynthetic efficiency in rice, suggesting that optimizing LW may be a potential strategy for enhancing A without necessarily improving iWUE.