Dayong Cui

Cadmium (Cd) contamination poses a significant threat to wheat productivity and food safety. This study demonstrates that TaMAN7-4B, which encodes an endo-β-mannanase involved in the metabolism of cell wall mannans, is significantly upregulated in response to Cd stress, thereby enhancing Cd tolerance by increasing the root cell wall mannan content and facilitating Cd sequestration. Furthermore, we identified the transcription factor TabZIP27 as a direct regulator of TaMAN7-4B expression. TabZIP27 is phosphorylated by the kinase TaCIPK16, which stabilizes TabZIP27 by suppressing its proteasome-dependent degradation. This phosphorylation event subsequently promotes the transcription of TaMAN7-4B, resulting in enhanced Cd binding within the root cell walls and reduced translocation of Cd from roots to shoots. Our findings elucidate a novel regulatory module, TaCIPK16-TabZIP27-TaMAN7-4B, which governs Cd accumulation in wheat, thereby providing potential targets for the breeding of low-Cd cultivars.

Accurate monitoring of photosynthetic phenotypes is fundamental for breeding high photosynthetic-efficiency wheat cultivars, and UAV remote sensing provides an effective approach for their large-scale identification. However, single photosynthetic parameters are limited in comprehensively evaluating crop photosynthetic efficiency. This study integrated multiple photosynthetic phenotypic parameters using principal component analysis (PCA) and the CRITIC objective weighting method (PCA-CRITIC) to construct a Comprehensive High Photosynthetic-Efficiency Phenotypic Index (CHPPI) for winter wheat. Concurrently, multispectral vegetation indices (MSVI), RGB vegetation indices (RGBVI), texture features (TF), and their combination, Comprehensive Multispectral-Visible-Texture Features (CMVTF), were extracted from UAV multimodal remote sensing data. Based on these features, four feature selection methods, namely PCC, VIP, SPA, and UVE, were evaluated in combination with five machine learning algorithms, including KNN, DT, SVR, RF, and XGBoost, to precisely estimate the CHPPI across key growth stages. The results demonstrated that the CHPPI exhibited significant cultivar variations across growth stages. Cultivars SH06144 and Liangxing19 consistently maintained high photosynthetic efficiency levels. The fused feature set CMVTF derived from multimodal remote sensing data outperformed individual feature categories, and the feature subset selected by the UVE method most significantly enhanced model accuracy. Regarding algorithms, the ensemble-based XGBoost and RF models markedly surpassed traditional machine learning algorithms. Specifically, the CMVTF-UVE-XGBoost model achieved the optimal comprehensive performance, yielding an R² of 0.862, an RMSE of 0.032, and an MAE of 0.027 on the testing set, with its spatial distribution estimations highly consistent with measured values. This study provides robust technical support for the rapid and large-scale screening of high photosynthetic-efficiency wheat breeding materials.

Soil salinity is a major constraint on global agricultural productivity. This study evaluated the efficacy of a cell-free extract from Trichoderma hamatum (designated BEYF) in enhancing salt stress tolerance in lettuce (Lactuca sativa). Lettuce plants under normal and salt-stressed conditions exposed to 200 mM NaCl were treated with either water or YF (the working solution of BEYF) at concentrations of 0.05, 0.10, and 0.25 mg/L. Compared to the control, YF application significantly improved plant growth under salt stress, as indicated by increased plant height, biomass, leaf area, and other agronomic traits. Physiologically, YF mitigated oxidative membrane damage, as indicated by reduced electrolyte leakage and malondialdehyde (MDA) content, while promoting the accumulation of the osmoprotectant proline. Histochemical staining further confirmed that YF effectively suppressed hydrogen peroxide (H₂O₂) accumulation and preserved cell viability under salt stress. At the molecular level, YF significantly up-regulated the expression of key stress-responsive genes, including those involved in abscisic acid biosynthesis (NCED1, NCED2), signaling (WRKY58), and proline synthesis (P5CSs). Collectively, our findings demonstrate that BEYF enhances lettuce salt tolerance through integrated physiological, cellular, and transcriptional adaptations, supporting its potential as a sustainable biostimulant for improving crop cultivation in saline soils.

SUMMARY: Flowering is a crucial developmental process in angiosperms. However, the underlying mechanisms remain to be elucidated. In this study, we identify INDETERMINATE DOMAIN (IDD) transcription factors (TFs), IDD14, IDD15, and IDD16, as redundant negative regulators of flowering time in Arabidopsis. The idd14‐1 idd15‐5 idd16‐1 triple mutant displays early flowering, while the gain‐of‐function mutation in idd14‐1D results in delayed flowering under long‐day conditions. Gene expression analysis shows that the florigen gene FLOWERING LOCUS T ( FT ) is activated in idd14‐1 idd15‐5 idd16‐1 but suppressed in idd14‐1D . Further analyses show that IDD14 could directly bind to the promoter of FT to suppress its expression. Moreover, IDDs interact with DELLAs in vitro and in vivo , and DELLAs enhance the inhibition ability of IDD14 on FT . Genetic and physiological analyses further support that IDD s regulate flowering through their dependence on FT and are partially involved in DELLA‐mediated flowering time regulation. Taken together, our findings suggest that a subfamily of IDD TFs may function as new components of DELLA‐mediated gibberellin signaling to negatively modulate flowering time by repressing the expression of FT .

Challenging environmental conditions are major factors that severely affect plant growth and limit agricultural productivity. To mitigate these stresses, plants have evolved various adaptive mechanisms. Among these, Late Embryogenesis Abundant (LEA) proteins play a pivotal role in responding to abiotic stresses and participate in a reciprocal regulatory network with the abscisic acid (ABA) signaling pathway. However, the precise molecular mechanisms underlying this reciprocity and the full composition of this network require systematic integration. This review synthesizes recent advances to propose a novel “ABA-LEA feedback loop” model and presents a comprehensive analysis of the classification into seven groups, structural features, molecular functions and mechanisms by which LEA proteins contribute to plant stress resistance. Special emphasis is placed on the intricate interplay between LEA proteins and the ABA signaling pathway, encompassing both the ABA-dependent regulation of LEA expression and the reciprocal feedback exerted by LEA proteins on ABA signaling through mechanisms that influence ABA homeostasis and signaling. By synthesizing evidence for this reciprocal regulation, this review establishes a novel feedback loop model that redefines LEA proteins as active modulators rather than passive effectors in stress signaling, offering new theoretical targets for breeding stress-resilient crops.

Cellular asymmetry, which represents a fundamental characteristic of cell polarity, is prominently illustrated by the apical‐basal localization of PIN‐FORMED (PIN) auxin efflux carriers in Arabidopsis thaliana . Although the maintenance of PIN polarity at the plasma membrane (PM) relies on endomembrane trafficking, the pivotal factors responsible for recruiting PIN proteins to the PM remain largely unknown. In this study, we discover that EXO70G1 displays a polarized distribution at the PM in root cells. Acting as a putative subunit of the exocyst complex, which mediates the tethering of exocytic vesicles to the PM, EXO70G1 exhibits continuous recycling foci at the PM, and its dynamic behavior is akin to that of SEC6 and SEC8. Disruption of EXO70G1 and its homolog EXO70G2 in Arabidopsis reduces auxin accumulation and primary root length. Importantly, the recycling of PIN2 from the brefeldin A (BFA) compartment to the PM is compromised, and the abundance of PIN2 at the PM is reduced in the exo70G1 exo70G2 backgrounds. Interestingly, live‐cell imaging reveals that the polarity of EXO70G1 is established during cytokinesis, prior to that of PIN2, and is maintained throughout the subsequent phases of cell elongation and differentiation. When the lipid raft was disturbed, the accumulation of EXO70G1 at the PM decreased. Our findings highlight the crucial role of EXO70G1 in root development by providing positional cues that facilitate the recycling efficiency of PIN2 to the PM.

A robust framework for identifying superior materials and facilitating the development of breakthrough crop cultivars. This Research Topic focuses on recent advances in germplasm and gene discovery related to abiotic stress management in crops, aiming to enhance our understanding of crop responses to abiotic stresses and promote the efficient utilization of genetic resources to support sustainable agricultural practices. Out of 30 submissions, 17 articles were accepted following rigorous peer review, including 16 research papers and 1 review. These studies cover various abiotic stresses-such as cadmium, calcium, CO₂, cold, drought, heat, salt, selenium, waterlogging, and zinc-affecting crops such as peanut, rice, soybean, tobacco, and wheat. The findings offer valuable insights for exploring stress responses across diverse plant species.Three articles exmine physiological and biochemical responses to abiotic stresses. In soybean, foliar applications of amino acids and zinc not only maintained yield but also enhanced pod and branch numbers while promoting zinc biofortification. Another study explored the unclear relationship between anthocyanin levels and salt stress in peanut, demonstrating that high anthocyanin content activates the antioxidant system, alleviating oxidative stress, and preserving photosynthetic efficiency under salt conditions. In another experiment, calciumsensitive and calcium-tolerant peanut cultivars were compared under calcium-deficient conditions. Calcium-sensitive cultivars exhibited a 22.75% reduction in yield, along with increased activities of antioxidant enzymes (SOD, POD, and CAT) and elevated MDA content.In contrast, calcium-tolerant cultivars maintained stable yield and physiological performance, underscoring calcium's essential role in crop productivity.Several studies focused on molecular responses to abiotic stresses. In rice, sequencing of 541 cultivars followed by genome-wide association studies identified a candidate gene, OsTMF, as responsive to salt stress. Knockout experiments revealed that OsTMF promotes germination under salt conditions, demonstrating its potential utility for salt-tolerant breeding.In wheat, researchers employed chromosome engineering strategies to introgress chromosome 7el1L from Thinopyrum species into wheat chromosome 7AL, producing recombinant lines with enhanced salt tolerance. These lines exhibited notable physiological changes under salt stress, including increased photosynthetic pigment levels, accumulation of compatible solutes, and reduced antioxidant content (such as ascorbate).In peanut, bioinformatics analysis identified 16 TPS (Trehalose-6-phosphate synthase) and 17 TPP (Trehalose-6-phosphate phosphatase) genes involved in cold stress responses. Notably, AhTPS9 exhibited differential expression under cold treatment. Overexpression of AhTPS9 in Arabidopsis thaliana improved cold tolerance by stabilizing the photosynthetic system and regulating sugar metabolism, making this gene a promising target for cold-tolerant peanut breeding.In chickpea, Meta-QTL analysis revealed several genes involved in heat stress response, including pollen receptor-like kinase 3, flowering-promoting factor 1, and heat stress transcription factor A-5. These genes influence flowering time, pollen germination, and overall plant development, offering valuable targets for heat-tolerant breeding programs.In Brassica juncea, BjNRAMP1 (Natural Resistance-Associated Macrophage Protein 1) was identified as a key gene involved in cadmium stress tolerance. Expressed in vascular tissues of roots, leaves, and flowers, BjNRAMP1 facilitates cadmium and manganese accumulation when introduced into yeast and Arabidopsis, though its overexpression negatively affects plant growth.A study in tobacco identified members of the Shaker K⁺ channel family, with NtSKOR1B upregulated under salt stress. Mutants lacking ntskor1 exhibited increased biomass and higher K⁺ content under salt stress, highlighting its potential role in improving salt tolerance. Another study used miRNA sequencing to explore drought stress responses in tobacco. Thirteen miRNAs were differentially expressed under drought stress, including both known (e.g., nta-miR156b, nta-miR166a) and novel miRNAs (e.g., novel-nta-miR156-5p, novel-nta-miR209-5p). These miRNAs targeted genes involved in cell wall expansion, such as EXT1 and RWA2, whose expression decreased under drought but recovered with selenium treatment. A key regulatory pathway-novel-nta-miR97-5p-LRR-RLK-catechin-was identified, highlighting its importance in drought tolerance.In Medicago sativa (alfalfa), RNA-seq analysis of plants treated with methyl jasmonate (JA) and salt stress revealed two co-expression modules associated with antioxidant enzyme activity and ion homeostasis. Core genes identified included pyruvate decarboxylase and RNA demethylase, suggesting that JA enhances salt tolerance by modulating antioxidant responses and maintaining ion balance.The Research Topic also includes studies on non-crop plants, offering insights applicable to crop improvement. For example, Kandelia obovata exhibits high tolerance to salt and waterlogging. RNA-seq analysis identified 45 salt-responsive and 16 waterlogging-responsive genes involved in secondary metabolism, highlighting potential targets for enhancing abiotic stress tolerance in crops.

Summary: The INDETERMINATE DOMAIN (IDD) transcription factors mediate various aspects of plant growth and development. We previously reported that an Arabidopsis IDD subfamily regulates spatial auxin accumulation, and thus organ morphogenesis and gravitropic responses. However, its functions in stress responses are not well defined. Here, we use a combination of physiological, biochemical, molecular, and genetic approaches to provide evidence that the IDD14 cooperates with basic leucine zipper‐type binding factors/ABA‐responsive element (ABRE)‐binding proteins (ABRE‐binding factors (ABFs)/AREBs) in ABA‐mediated drought tolerance. idd14‐1D, a gain‐of‐function mutant of IDD14, exhibits decreased leaf water loss and improved drought tolerance, whereas inactivation of IDD14 in idd14‐1 results in increased transpiration and reduced drought tolerance. Altered IDD14 expression affects ABA sensitivity and ABA‐mediated stomatal closure. IDD14 can physically interact with ABF1–4 and subsequently promote their transcriptional activities. Moreover, ectopic expression and mutation of ABFs could, respectively, suppress and enhance plant sensitivity to drought stress in the idd14‐1 mutant. Our results demonstrate that IDD14 forms a functional complex with ABFs and positively regulates drought‐stress responses, thus revealing a previously unidentified role of IDD14 in ABA signaling and drought responses.