Timely and accurate forecasting of crop yields is critical for food management and trade.  However, only limited research has explored the impact of integrating crop phenotypic parameters (CPPs) with unmanned aerial vehicle (UAV) data across different phenological stages on maize yield prediction.  The extent to which multi-temporal data enhances the accuracy and reliability of yield projections compared to mono-temporal data has yet to be systematically investigated.  To attain the proper balance between accuracy and cost in crop yield estimation, this study proposed a structured framework for identifying the optimal phenological periods for summer maize yield prediction using UAV-based multispectral data.  Three classical methods of custom mean decrease accuracy (C-MDA), optimal parameters-based geographical detector (OPGD), and grey relational analysis (GRA) were first used to sort and screen both the CPPs and vegetation indices (VIs) derived from UAV-based information over six growth stages.  Ridge regression models based on multi-temporal data combinations and mono-temporal data were established separately, and their performance in yield prediction were compared to identify the optimal phenological stages and the corresponding key factors.  Our results showed that C-MDA was much better at factor screening and ranking compared to OPGD and GRA.  The green normalized difference vegetation index (GNDVI), normalized difference vegetation index (NDVI), and normalized difference red edge index (NDRE) emerged as the top-performing VIs, while the leaf area index (LAI) and above ground biomass (AGB) proved to be the most effective CPPs.  When predicting yield using only mono-temporal data, the dough stage delivered the highest predictive accuracy (R²=0.871, RMSE=0.407 t ha^–1), while the tasseling stage was the earliest that achieved yield estimates with acceptable precision (R²=0.810, RMSE=0.493 t ha^–1).  In contrast, the integration of UAV data from different crop growth stages markedly enhanced the accuracy of yield estimation.  Combinations of data from the tasseling, silking, and dough stages were recommended as the best option (R²=0.942, RMSE=0.291 t ha^–1).  These findings indicate that the precise estimation of maize yields in smallholder fields may be attainable, and present both substantial theoretical insights and practical benefits for the advancement of precision agriculture.

Cold stress represents a critical constraint on crop productivity, particularly in temperate climates.  Despite the established role of abscisic acid (ABA) in cold stress responses, the precise mechanisms through which transcription factors mediate ABA-dependent cold tolerance remain elusive.  Here, we identify VaMYB4a, a MYB transcription factor from Vitis amurensis Rupr.  (Amur grape), as a key regulator of cold tolerance.  It integrates ABA signaling with the CBF (C-repeat binding factors)-COR (cold-regulated) pathway to orchestrate cold stress adaptation.  Through a combination of overexpression and CRISPR/Cas9-mediated knockout lines in Arabidopsis thaliana, grape callus, and Vitis vinifera L. seedlings, we demonstrate that VaMYB4a enhances freezing tolerance by promoting osmotic regulation, reactive oxygen species (ROS) scavenging, and stomatal closure.  VaMYB4a functions as a homo-dimer, with its C-terminal domain being essential for transcriptional activation.  Mechanistically, VaMYB4a directly upregulates CBF and COR genes while fine-tuning ABA signaling components such as ABI1 and ABF4.  Notably, ABA exhibits a dual role: enhancing VaMYB4a-mediated freezing tolerance under short-term stress but attenuating its effects during prolonged cold exposure, revealing an intricate regulatory crosstalk between cold and hormonal pathways.  Our work not only advances the molecular understanding of cold adaptation but also provides a promising genetic target for developing stress-resilient grape varieties to mitigate the impacts of climate change.

Melon (Cucumis melo) is an economically important horticultural crop cultivated worldwide.  NAC (NAM/ATAC/CUC) transcription factors play crucial roles in the transcriptional regulation of various developmental stages in plant growth and fruit development, but their gene functions in melon remain largely unknown.  Here, we identified 78 CmNAC family genes with an integrated and conserved no apical meristem (NAM) domain in the melon genome by performing genome-wide identification and bioinformatics analysis.  Transcriptome data analysis and qRT-PCR results showed that most CmNACs are specifically enriched in either the vegetative or reproductive organs of melon.  Through genetic transformation, we found that overexpression of CmNAC34 in melons led to early ripening fruits, suggesting its positive role in promoting fruit maturation.  Using yeast two-hybrid and bimolecular fluorescence complementation assays, we verified the direct protein interaction between CmNAC34 and CmNAC-NOR.  The expression patterns of CmNAC34 and CmNAC-NOR were similar in melon tissues, and subcellular localization revealed their nuclear protein characteristics.  We transformed CmNAC-NOR in melon and found that its overexpression resulted in early ripening fruits.  Then, the yeast one-hybrid and dual luciferase reporter gene assays showed that the CmNAC34 protein can bind to the promoters of two glyoxalase (GLY) genes, which are involved in the abscisic acid signal pathway and associated with fruit regulation.  These findings revealed the molecular characteristics, expression profiles, and functional patterns of the NAC family genes and provide new insights into the molecular mechanism by which CmNAC34 regulates climacteric fruit ripening.

The TSJT1 protein belongs to the class-II glutamine amidotransferase (GATase) superfamily.  Research on the functions and underlying mechanisms of TSJT1 in plants is limited.  In this study, the abscisic acid (ABA)-inducible gene IbTSJT1 was isolated from drought-tolerant sweetpotato line Xushu 55-2.  Its expression was strongly induced by PEG6000 and ABA.  The IbTSJT1 protein was localized in the nucleus and cell membrane.  IbTSJT1-overexpressing sweetpotato plants exhibited significantly enhanced drought tolerance.  Their ABA and proline contents and superoxide dismutase (SOD) and peroxidase (POD) activities were increased, and their reactive oxygen species (ROS) scavenging-related genes were upregulated under drought stress.  The stomatal aperture assay confirmed that the IbTSJT1-overexpressing plants had greater sensitivity to ABA.  The results of yeast one-hybrid (Y1H) assay, electrophoretic mobility shift assay (EMSA), luciferase reporter assay and ChIP-qPCR assay indicated that IbABF2 can directly bind to the cis-acting ABA-responsive element (ABRE) in the IbTSJT1 promoter to activate the expression of IbTSJT1.  These findings suggest that IbTSJT1 mediates ABA-dependent drought stress responses and enhances drought tolerance by inducing stomatal closure and activating the ROS scavenging system in transgenic sweetpotato.  Our study provides a novel gene for improving drought tolerance in sweetpotato and other plants. 

Salt stress is a major constraint to crop productivity and quality.  The limited availability of salt-tolerant genes poses significant challenges to breeding programs aimed at enhancing salt tolerance.  Sorghum displays a remarkable ability to withstand saline conditions; therefore, elucidating the genetic underpinnings of this trait is crucial.  This study entailed a comprehensive resequencing of 186 sorghum accessions to perform a genome-wide association study (GWAS) focusing on relative root length (RL) and root fresh weight (RFW) under salt stress conditions.  We identified eight candidate genes within a co-localized region, among which SbTEF1 - a gene encoding a transcription elongation factor protein - was deemed a potential candidate due to its annotation and expression pattern alterations under salt stress.  Haplotype analysis, gene cloning, linkage disequilibrium (LD) analysis, and allele effect analysis revealed that PAV284, located in the promoter region of SbTEF1, modulated gene expression under salt stress, which, in turn, influenced sorghum seedlings’ salt tolerance.  PAV284 holds promise as a genetic marker for selecting salt-tolerant germplasm via marker-assisted breeding, enhancing the development of salt-tolerant sorghum cultivars.

Maize/soybean intercropping systems are commonly used in developing countries, but few studies have been performed to elucidate the differences in nutrient efficiency and rhizosphere microbiome, especially when maize is intercropped with different soybean varieties.  In this study, field experiments were conducted to compare the growth and yield of two soybean (Glycine max) varieties, BD2 and YC03-3, and one maize (Zea mays) variety, Huazhen, in mono-cropped and intercropped cultures.  The plant biomass and N content of both crops in BD2/maize intercropping were significantly improved compared to their monoculture, but no such effects were observed in the plants of YC03-3/maize intercropping.  The yield of BD2 intercropped with maize exhibited a 37.5% increment above that of BD2 in monoculture.  Moreover, 19.2–29.1% longer root length of maize and 19.0–39.4% larger root volume of BD2 were observed in BD2/maize intercropping than in monoculture, but no growth advantage was observed in YC03-3/maize intercropping.  Maize showed root avoidance when intercropped with BD2, but space competition when intercropped with YC03-3.  16S rRNA amplicon sequencing showed that compared with the monoculture system, rhizobacteria community composition in BD2/maize intercropping changed more significantly than that of the YC03-3/maize intercropping system.  In BD2/maize intercropping, most of the rhizobacteria community biomarker bacteria of BD2 were positively correlated with plant biomass, as well as plant P and N content.  Maize tended to recruit Rhizobiales and Proteobacteria, which showed positive correlation with plant biomass and N content, respectively, as well as soil available N.  In conclusion, soybean varieties determined the advantages of maize/soybean intercropping through root–root interactions and modification of rhizobacteria communities.  Our insight emphasizes a linkage between root traits and the rhizobacteria community, which shows the importance of optimizing intercropping systems by selection of appropriate crop varieties.

Species closely related to wheat are important genetic resources for agricultural production, functional genomics studies and wheat improvement.  In this study, a wheat gene related to regeneration, TaWOX5, was applied to establish the Agrobacterium-mediated transformation systems of Triticum monococcum, hexaploid triticale, and rye (Secale cereale L.) using their immature embryos.  Transgenic plants were efficiently generated.  During the transformation process, the Agrobacterium infection efficiency was assessed by histochemical staining for β-glucuronidase (GUS).  Finally, the transgenic nature of regenerated plants was verified by polymerase chain reaction (PCR)-based genotyping for the presence of the GUS and bialaphos resistance (bar) genes, histochemical staining for GUS protein, and the QuickStix strip assay for bar protein.  The transformation efficiency of T. monococcum genotype PI428182 was 94.4%; the efficiencies of four hexaploid triticale genotypes Lin456, ZS3297, ZS1257, and ZS3224 were 52.1, 41.2, 19.4, and 16.0%, respectively; and the transformation efficiency of rye cultivar Lanzhou Heimai was 7.8%.  Fluorescence in situ hybridization (FISH) and genomic in situ hybridization (GISH) analyses indicated that the GUS transgenes were integrated into the distal or near centromere (proximal) regions of the chromosomes in transgenic T. monococcum and hexaploid triticale plants.  In the transgenic hexaploid triticale plants, the foreign DNA fragment was randomly integrated into the AABB and RR genomes.  Furthermore, the transgene was almost stably inherited in the next generation by Mendel’s law.  The findings in this study will promote the genetic improvement of the three plant species for grain or forage production and the improvement of cereal species including wheat for functional genomics studies.

Avian pathogenic Escherichia coli (APEC) could cause colibacillosis, which is economically devastating to poultry industries worldwide. The bacterial membrane is critical to its environment adaptability and virulence. The inner membrane protein TolA maintains membrane integrity, but the roles of which in fitness and pathogenesis of APEC are not completely understood. Thus, the tolA gene mutant and complemented strains of APEC were constructed and characterized. We found that mutant strain ΔtolA was damaged in inner and outer membranes, and showed altered morphology, impaired flagella production, reduced motility, increased outer membrane vesicles (OMVs) production, decreased resistance to antibiotics and environmental stress. Deletion of tolA gene resulted in a significant decrease in biofilm formation and interbacterial competition, due to the downregulated expression of biofilm-associated genes and type VI secretion system (T6SS) genes, respectively. In addition, the mutant strain exhibited diminished serum bactericidal resistance, reduced cell infection capacity, decreased intracellular survival, consequently, leading to attenuated bacterial survival and virulence in mice. Compared with the wild-type and complemented strains, mutant strain induced less expression of inflammatory cytokine interleukin 1 beta (IL-1β) in HD-11 macrophages, consistent with the pathological damage in mice. In conclusion, inner membrane protein TolA contributed to the antibiotic resistance, environment adaptability, biofilm formation and virulence of APEC.

The universal stress proteins (USPs) play important roles not only in abiotic stress tolerance but also in plant growth and development.  However, the role of USPs in regulating starch biosynthesis has not been reported.  In this research, the IbUSP17 gene was isolated from a sweetpotato line H283 with high starch content.  The IbUSP17 protein was localized in the nucleus. IbUSP17 were highly expressed in the lines with high starch content and during rapid thickening and starch accumulation period of storage roots.  Overexpressing IbUSP17 increased storage root starch content, especially amylopectin proportion, without storage root yield penalty in sweetpotato.  Overexpression of IbUSP17 up-regulated the genes involved in starch biosynthesis and increased the activities of enzymes related to amylopectin biosynthesis.  The contents of components related to starch biosynthesis were also increased in the IbUSP17-overexpressing plants.  Silencing this gene produced opposite effects.  These results suggest that overexpression of IbUSP17 increases starch content through up-regulating the genes involved in starch biosynthesis and increasing the activities of enzymes related to starch biosynthesis, especially amylopectin biosynthesis.  It is the first time to reveal the role of the USP gene in starch biosynthesis.  This gene is expected to be used to increase starch yield and improve starch quality in sweetpotato.

Wheat is a major staple food and primary source of dietary minerals in the world, providing vital trace elements. Copper (Cu) is an essential nutrient for the development, and it plays a crucial role in various metabolic and biochemical reactions in wheat. Meanwhile, Cu is distributed in human tissues and organs and involved in human physiological functions. Cu deficiency may lead to abnormal hair, anemia, abnormal bones and even disorders of brain function. In this study, we detected QTLs for Cu content in two recombinant inbred line (RIL) populations, including 164 F₆ RILs from a cross between Avocet and Chilero (AC population) and 175 F₆ RILs from a cross between Avocet and Huites (AH population). Four QTLs (QGCu.haust-AH-7D, QGCu.haust-AC-5B.2, QGCu.haust-AH-5B.1, QGCu.haust-AH-1B) were detected on chromosomes 1B, 5B and 7D across more than two environments by QTL mapping with diversity array technology (DArT) marker. QGCu.haust-AH-7D, a major and stable QTL was detected in three environments explaining the phenotypic variance (PVE) from 8.70 to 9.34% with a physical interval of 99.96 to 100.66 Mb. QGCu.haust-5B, a co-localization and major QTL ranged from 446.01 to 450.57 Mb and explained 11.28% to 26.02% of the phenotypic variance between QGCu.haust-AC-5B.2 (421.44-607.84 Mb) in AC population and QGCu.haust-AH-5B.1 (446.01 to 450.57 Mb) of AH population in two environments. QGCu.haust-AH-1B, a stable QTL was explained 9.79 to 15.96% of the phenotypic variance with a physical interval of 340.46 Mb to 416.77 Mb in two environments. These favorable alleles of QGCu.haust-AH-1B, QGCu.haust-5B and QGCu.haust-AH-7D significantly increased grain Cu content by 13.63, 14.34 and 10.54% (P<0.01) compared with lines carrying unfavorable alleles. Using pyramiding and pleiotropic effects analysis with quality traits, the pyramiding of favorable alleles of the three QTLs significantly increased grain Cu content, grain protein content, wet gluten content and sedimentation value by 30.82, 18.65, 19.16, and 52.43% (P<0.01), respectively. A high-throughput competitive allele specific PCR (KASP) marker, KACu-5B-2 was developed and verified in the natural population (ZD population). Genetic effect revealed that favorable haplotype Hap1 significantly rised up grain Cu content, grain protein content, wet gluten content and sedimentation value by 8.1%, 5.12, 5.32, and 5.52% compared to Hap2 with unfavorable haplotype (P<0.05). This study provides a theoretical basis and technical support for cloning wheat grain Cu content related genes, facilitating molecular marker-assisted selection (MAS) and optimizing Cu-enriched biofortification breeding strategies.