Intronless genes are a feature of prokaryotes; however, they are widespread and unequally distributed among eukaryotes and represent an important resource to study the evolution of gene architecture. Although many databases on exons and introns exist, there is currently no cohesive database that collects intronless genes in plants into a single database. In this study, we present the Poaceae Intronless Genes Database (PIGD), a user-friendly web interface to explore information on intronless genes from different plants. Five Poaceae species, Sorghum bicolor, Zea mays, Setaria italica, Panicum virgatum and Brachypodium distachyon, are included in the current release of PIGD. Gene annotations and sequence data were collected and integrated from different databases. The primary focus of this study was to provide gene descriptions and gene product records. In addition, functional annotations, subcellular localization prediction and taxonomic distribution are reported. PIGD allows users to readily browse, search and download data. BLAST and comparative analyses are also provided through this online database, which is available at http://pigd.ahau.edu.cn/ . PIGD provides a solid platform for the collection, integration and analysis of intronless genes in the Poaceae. As such, this database will be useful for subsequent bio-computational analysis in comparative genomics and evolutionary studies.

Continuous cropping obstacles (CC), typical of negative plant–soil feedback, have become a non-negligible constraint to the development of agriculture. In order to investigate the main direct drivers influencing the formation of CC soils from the rhizosphere of CC, tobacco fields were collected and their physicochemical properties, microbial community, and metabolomics were measured and analyzed. We also built a mixed linear model to evaluate the impact of these factors on CC. The results suggested that the pH, available potassium (AK), and zinc (Zn) were significantly higher in CC than in normal tobacco (NOR). However, the content of available nitrogen (AN) decreased significantly. Alpha diversity of the bacterial community was significantly reduced. Bacterial community structure also varied significantly in CC. The study identified an ecological cluster with a significant negative correlation with the above-ground biomass of plants. In this cluster, the pathogenic microbiome increased and the beneficial microbiome decreased. The orthogonal partial least squares discriminant analysis (OPLS-DA) indicated clear variations in the metabolomic profiles of the rhizosphere soil between the CC and the NOR. There was an accumulation of toxic compounds and a decrease of beneficial compounds in rhizosphere soils with CC. The mixed linear model showed that only microbiome and metabolites, rather than the soil’s physicochemical properties, significantly affected plant above-ground biomass. According to the model’s standardized coefficients, metabolites contributed more to the continuous crop obstacles than the microbial community. The soil’s physicochemical properties do not directly cause the emergence of CC. The allelochemicals and microbial community are the main direct obstacles to continuous cropping in tobacco, and allelochemicals contribute more than the microbial community.

Near infrared reflectance spectroscopy (NIRS) and reference data were used to determine the amylose contents of single maize seeds to enable rapid, effective selection of individual seeds with desired traits. To predict the amylose contents of a single seed, a total of 1069 (865 as calibration set, 204 as validation set) single seeds representing 120 maize varieties were analyzed using chemical methods and performed calibration and external validation of the 150 single seeds set in parallel. Compared to various spectral pretreatments, the regression of partial least squares (PLS) with mathematical treatment of Harmonization showed the final optimization. The single-seed amylose contents showed the root mean square error of calibration (RMSEC) of 2.899, coefficient of determination for calibration (R²) of 0.902, and root mean square error of validation (RMSEV) of 2.948. In external validations, the coefficient of determination in cross-validation (r²), root mean square error of the prediction (RMSEP) and ratio of the standard deviation to SEP (RPD) were 0.892, 2.975 and 3.086 in the range of 20–30%, respectively. Therefore, NIRS will be helpful to breeders for determining the amylose contents of single-grain maize.

N-(2-Chloro-4-pyridyl)-N'-phenylurea (CPPU) is an efficient exogenous plant growth regulator that plays a crucial role in regulating physiological processes such as cell division, cell differentiation, and organogenesis, significantly influencing the growth and development of plants. However, there is still a lack of systematic research on the effects of CPPU on the development of upper tobacco leaves and its mechanism in improving the quality of flue-cured tobacco. This study systematically revealed the core regulatory functions of cell division-related hormones such as trans-zeatin (tZ) and brassinolide (BL) in the development of upper leaves, and confirmed that their effects have a clear concentration dependence. Among them, 20 mg L^-1 CPPU treatment resulted in the best effect, increasing the total yield of upper leaves by 12.86 %. The application of CPPU significantly promoted the expansion of epidermal cells and palisade tissue cells, increased leaf thickness and leaf area, and improved the maturity and quality characteristics of the leaves by accelerating the degradation of cell wall components and reducing the pectin content by 36.92 %. Molecular mechanism analysis indicated that CPPU regulates the expression of hormone-related genes such as auxin (IAA), gibberellin (GA), abscisic acid (ABA), and BL to coordinate the orderly progression of cell division, cell expansion, and the mature stage. Its specific mechanism includes inhibiting the expression of cytokinin oxidase gene (CKX) to maintain a higher tZ level, regulating the GA metabolic pathway to prevent excessive vegetative growth, and activating CYCD3-like genes to promote cell cycle transition. In summary, CPPU achieves the coordinated improvement of tobacco yield and quality by constructing a multi-hormone co-regulation network. This study not only provides practical agronomic control strategies for high-quality and efficient tobacco cultivation but also lays a theoretical foundation for in-depth analysis of the molecular regulatory mechanism of CPPU in tobacco growth and development.

The T-DNA insertion technique is widely used in molecular breeding for its stable inheritance and low copy number in the plant genome. In our experiment, a transfer DNA (T-DNA) insertion grain of m-1a in rice was identified. Phenotypic analysis revealed that the grains appeared chalky and became extensive. The epidermis was shrinking. Meanwhile, the amylose contents of the seeds decreased significantly, and the expression of the most starch synthesis genes was obviously downregulated. Using the whole-genome sequencing and chromosome step method, the insertion position was uncovered and only located in Chr11 between 23266185 and 23266186 bp. These results may provide material for opening up new T-DNA insertion position points and a theoretical basis for rice molecular breeding.