In 2024, the numbers of original research articles published by Chinese plant scientists in mainstream plant science journals increased significantly compared with that in 2023, and important advances have been made in the fields of plant hormone regulation, pathology, synthetic biology, stress resistance mechanism, phylogenetics and genomics. Among them, “Characterization and Heterologous Reconstitution of Taxus Biosynthetic Enzymes Leading to Baccatin III”, and “Reciprocal Conversion Between Annual and Polycarpic Perennial Flowering Behavior in the Brassicaceae” were selected as two of the “Top Ten Advances in Life Sciences in China” in 2024. Here we summarize the achievements of plant science research in China in 2024, by briefly introducing 50 representative important research advances, so as to help readers understand the trend of plant science development in China, and evaluate future research direction to meet major national strategic needs.

INTRODUCTION Trehalose-6-phosphate synthase (TPS) is a key enzyme involved in the synthesis of trehalose and has been reported to participate in regulating photosynthesis, carbohydrate metabolism, growth and development, and stress responses in various species. Currently, reports on TPS genes in soybean are scarce.

RATIONALE  TPS is a stable non-reducing disaccharide, whose synthesis, decomposition and regulation not only provide energy for plant, but also play an important role in plant growth and development and stress tolerance. The in-depth study of soybean TPS genes and its relationships with salt stress is of great significance in elucidating the molecular mechanism of soybean salt tolerance and improving soybean yield.

RESULTS This study identified 20 soybean TPS genes and their associated 10 conserved protein motifs in the soybean genome. Molecular analysis of the promoter elements revealed that the TPS gene promoters are rich in stress-responsive elements. After salt stress treatment, the expression of 17 TPS genes changed, with 12 genes up-regulated and 5 genes down-regulated. Haplotype and selection analyses revealed two major allelic variations in TPS8, TPS13, TPS15, TPS17, and TPS18. Notably, variants carrying TPS15^H2, TPS13^H2, TPS17^H2, and TPS18^H2 were significantly enriched in improved cultivars that underwent strong artificial selection.

CONCLUSION This study reveals the molecular characteristics of the soybean TPS gene family, their expression patterns under salt stress, and their evolutionary history, providing a theoretical basis and genetic material for further elucidating the functions of soybean TPS genes and breeding salt-tolerant soybean varieties.

TPS genes were subjected to intense artificial selection. The natural variations of TPS8, TPS13, TPS15, TPS17, and TPS18 have been subjected to strong artificial selection during soybean domestication and improvement, with the variants carrying TPS15^H2, TPS13^H2, TPS17^H2, and TPS18^H2 being heavily enriched in improved cultivars.

INTRODUCTION Tomato (Solanum lycopersicum), a significant warm-season and water-dependent vegetable crop, is extensively cultivated worldwide. Whether grown in open fields or protected environments, tomatoes frequently encounter various environmental stresses, including drought and low temperatures, which significantly impact their yield and quality. Transcription factors play a pivotal role in plant stress responses by modulating the expression of specific target genes, thereby transmitting perceived stress signals downstream. WRKY transcription factors in tomatoes are known to regulate responses to multiple abiotic stresses. However, the specific role of the tomato SlWRKY45 in abiotic stress responses remains unclear.

RATIONALE Studies have demonstrated that WRKY transcription factors play a crucial regulatory role in plant responses to abiotic stress. As an important economic vegetable crop, tomato is susceptible to various environmental stresses during its growth and development. By genetically overexpressing SlWRKY45 in tomato and investigating its function under low-temperature and drought stress conditions, the findings can provide a theoretical foundation for understanding the complex regulatory mechanisms of WRKY transcription factors. Additionally, this research offers valuable candidate genes for breeding stress-resistant tomato varieties.

RESULTS Expression analysis revealed that low-temperature, drought, and abscisic acid (ABA) treatments significantly induced the expression of SlWRKY45. Overexpression of SlWRKY45 enhanced the resistance of tomato plants to drought and low-temperature stresses. Under drought and low-temperature conditions, the photosynthetic indices, antioxidant enzyme activities, and proline (Pro) contents in SlWRKY45 overexpression lines were significantly higher than those in wild-type (WT) plants. Conversely, the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA) levels in SlWRKY45-OE plants was significantly lower than in WT plants under the same stress conditions. Transcriptome data analysis indicated that SlWRKY45 regulates tomato's response to low-temperature stress primarily by influencing antioxidant enzyme activities and stress response pathways. Dual-luciferase assays demonstrated that SlWRKY45 could directly activate the expression of SlPOD1. Furthermore, the interaction between SlWRKY45 and SlWRKY46 was confirmed through yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays.

CONCLUSION Our findings demonstrate that SlWRKY45 positively regulates drought resistance and low-temperature tolerance in tomato. Additionally, SlWRKY45 can interact with SlWRKY46 and directly activate the expression of SlPOD1. These results offer valuable insights for further research into the regulatory mechanisms underlying abiotic stress responses and provide potential gene resources for genetic improvement through molecular breeding.

Phenotypes of SlWRKY45-overexpressing and wild-type plants under drought and low-temperature treatments

INTRODUCTION: Identification of salt-alkali tolerant germplasm in faba bean lays the foundation for the exploration of salt-alkali tolerant genes and for the selection and breeding of salt-alkali tolerant varieties, which is of great significance for the utilization of saline-alkali land.

RATIONALE: Most of the studies on the salt-alkali tolerance of faba beans were focused on the morphological and physiological traits of the aboveground parts, while there are few studies on the phenotypic traits of the roots. The root plays a crucial role in resisting salt-alkali stress. Deep research on the relationship between the phenotypic traits of the root and the salt-alkali tolerance of faba beans will help to comprehensively understand the physiological mechanism of the salt-alkali tolerance.

RESULTS: The results showed that: (1) Under salt-alkali stress, the root overlap number was mostly affected, it was followed by the coila number, while the average diameter of root was affected slightly; (2) Between the overlap number and total number of connection points, among the bifurcation number and the overlap number and total number of connection points, most of indicators were significant positively correlation (P<0.01), while there were significant negatively correlation (P<0.01) among the average diameter of root and total number of root, the number of root tip, total length of root, endpoint number, coila number, linking number, bifurcation number, overlap number and total number of connection points; (3) Total root surface area of root, total projected area of root, total length of root and total volume of root could be used as the key indicators to identify the salt-alkali tolerance of faba bean during the germination period; (4) Two salt-alkali tolerant accessions H0000809 and H0000653, and two salt-alkali sensitive accessions H0001714 and H0002622 were screened out; and (5) The 399 faba bean accessions were divided into 4 groups: group I, salt-alkali tolerance germplasm, accounting for 0.75%; group II, moderately salt-alkali tolerant germplasm, accounting for 8%; group III, weakly saline-tolerant germplasm, accounting for 52.88%; and group IV, salt-alkali sensitive germplasm, constituting 38.35%.

CONCLUSION: Variation and correlation of each index, and the key indicators used to identify salt-alkali tolerance were determined, extreme materials can be selected and used for future study of salt-alkali tolerance mechanisms in faba bean and the excavation of salt-alkali tolerance genes.

Phenotypic differences of faba bean germplasms with different levels of salt-alkali tolerance at different growth stages (A) Root phenotype differences of faba bean germplasms with different levels of salt-alkali tolerance at germination stage (bar=5 cm); (B) Plant phenotype differences of faba bean germplasms with different levels of salt-alkali tolerance at flowering stage (bars=1 cm).

INTRODUCTION Genetic diversity is the natural attribute of organisms formed in the long-term evolution process, which refers to the sum of all genetic variations of different individuals within a species or a group. Pepper (Capsicumspp.), a popular vegetable crop in China, is cultivated extensively with a substantial annual yield. Nevertheless, the widespread adoption of commercial pepper varieties has led to a gradual reduction in its genetic diversity, resulting in an increasing homogenization of germplasm resources. Given that germplasm forms the foundation for crop genetic improvement, maintaining rich genetic diversity is crucial for effective breeding.

RATIONALE On the other hand, morphological markers serve as a fundamental approach for investigating plant phenotypic diversity, as they allow researchers to evaluate the variations in marked samples through the observation of plant agronomic traits. On the other hand, molecular markers, particularly SSR (simple sequence repeat) markers, have gained widespread application in the breeding of new crop varieties and related fields due to their accuracy and reliability. This study focused on analyzing the diversity of 146 pepper germplasms in Inner Mongolia by employing both morphological traits and SSR markers.

RESULTS  We assessed 34 morphological traits of 146 pepper germplasms and evaluated their genetic diversity using 22 pairs of SSR primers. Our analysis revealed a high degree of diversity in the traits of these pepper lines. The results of phenotypic trait diversity analysis showed that the coefficient of variation of quality traits and quantitative traits ranged from 8.22% to 267.58% and 14.35% to 72.51%, respectively, and the Shannon-Wiener diversity index ranged from 0.04 to 1.91 and 1.58 to 2.02, respectively. The genetic diversity of pepper germplasm resources was rich. A total of 102 alleles were detected by 22 pairs of SSR fluorescent molecular markers, with an average of 4.636 alleles per pair of primers. The effective allelic variation ranged from 1.191 to 5.311, the Shannon-Wiener diversity index ranged from 0.345 to 2.056, and the polymorphic information content (PIC) ranged from 0.153 to 0.795. The average genetic distance of 146 pepper germplasm resources was 0.429. Phenotypic value clustering and principal component analysis categorized the 146 accessions into six distinct groups, while the analysis of the SSR marker data divided them into seven groups. Population genetic structure analysis further delineated the 146 pepper germplasms into two main groups. Most of these germplasms were high-generation breeding lines with high homozygosity. However, gene introgression was observed within Group1 and Group2.

CONCLUSION This study is the systematic analysis of the morphological characteristics, genetic diversity and population structure of 146 pepper germplasms, particularly by utilizing SSR fluorescent molecular markers. The high diversity in both morphological traits and genetic markers of these pepper germplasm resources indicated significant genetic differences in them. Consequently, this study provides a better understanding of the germplasm diversity and population genetic structure of these 146 pepper germplasms, establishing a theoretical foundation for future variety breeding efforts.

Genetic diversity analysis of 146 pepper germplasms. 146 pepper germplasms were categorized into six groups based on phenotypic markers and seven groups based on molecular markers, but the correlation between these clusters was weak (r=0.3967). Population genetic structure analysis further divided the germplasms into two distinct groups.

A rapid propagation system via tissue culture for Rosa multiflora was established using the stem segments with buds of the current-year as the experimental material. The results showed that the best explants were stem segments with axillary buds. The best disinfection method was to soak the explants in 75% ethanol for 30 seconds, and then soak them in 10% sodium hypochlorite solution for 20 minutes. The survival rate can reach 96%. The optimal bud-induction medium was MS+1.0 mg∙L^-1 6-BA+0.01 mg∙L^-1 NAA+0.1 mg∙L^-1 GA₃. The budding rate can reach 98% after 30 days of cultivation. WPM was the best basal medium for the proliferation of sterile regenerated plantlets, and the proliferation coefficient was 2.87. The best medium for rooting was 1/2MS+1.0 mg∙L^-1 6-BA+0.1 mg∙L^-1 NAA, and the rooting rate can reach 93%. The transplanting survival rate of sterile regenerated plantlets was 98%. On this basis, the transient expression system of R. multiflora was established. The results showed that the optimal transformation conditions for transient expression were OD₆₀₀ of 0.8 for the bacterium culture medium, vacuum negative pressure of -0.10 MPa and vacuum suction twice for 15 minutes each time. The transient expression efficiency can reach 96%. The results of this study laid a foundation for the establishment of regeneration and genetic transformation system of R. multiflora, and also provided technical support for studying on the gene function of Rosa plants.

Due to the long flowering cycle, unpredictable flowering period and low seed setting rate of most bamboo plants, bamboo breeding has been a challenge in the research of bamboo plants. Polyploid breeding, as a common mean of plant breeding, is able to obtain progeny with excellent traits through artificial induction. In bamboo breeding, there are fewer studies on polyploid breeding. In this study, based on the existing regeneration system of Dendrocalamus asper, the embryonic calluses of D. asper were treated with colchicine using the liquid suspension method and the solid medium mixed culture method, respectively. The results showed that, based on the differentiation and browning rates of the calluses, the better results were obtained by treating the calluses with 50 mg∙L^-1 colchicine for 48-72 hours using the liquid suspension method. A total of 54 regenerated plants, including 7 control plants, and 16 chromosome doubled plants were successfully obtained from D. asper using flow cytometry to test all the regenerated plants. In terms of chromosomal doubling, treatment with 100 mg∙L^-1 colchicine for 48 h produced the highest number of chromosome-doubled plants with a polyploidy rate of 54.54%. Compared with 6-ploid plants, the 12-ploid plants presented larger and thicker leaves, and larger lower epidermal stomata, implying their superiority in stress tolerance physiology. This study provides an efficient polyploid breeding technique based on the in vitro indirect regeneration system of bamboo, and offers a new solution for breeding new polyploid germplasm of bamboo.

Protein post-translational modifications (PTMs) serve as a crucial regulatory mechanism of protein function and play a significant role in rice seed development and endosperm starch biosynthesis. With advancements in proteomics technologies, numerous starch synthesis-related proteins in rice endosperm have been identified to undergo various PTMs. This review summarizes the proteomic analyses, modification sites, pathways, and biological functions of six major types of PTMs in starch synthesis-related proteins in rice endosperm: phosphorylation, lysine acetylation, succinylation, 2-hydroxyisobutyrylation, malonylation, and ubiquitination. Among these, protein phosphorylation has been the most extensively studied and is recognized as a key regulator of plant growth, development, and starch metabolism. Additionally, we discuss the potential roles of PTMs in grain filling, rice starch quality, and appearance. This review provides insights into the regulatory mechanisms of PTMs in starch synthesis-related proteins in rice endosperm, offering a valuable reference for breeding high-yield and high-quality rice varieties.

Charophytes and land plants form a monophyletic group known as Streptophyta. Fossil and molecular evidences suggest that land plants originated from charophytes. This article summarizes the 14 sequenced genomes of 10 species in charophytes and reviews the molecular mechanisms involved in the terrestrialization of plants, revealing the genomic basis for the pre-adaptation of charophytes that included the expansion of gene families regulating plant hormone signal transduction and encoding key transcription factors, as well as horizontal gene transfer. We elucidate with examples the helpful role of the whole-genome data of charophytes in transcriptomic and functional genomic discovery. Moreover, we discuss the importance of telomere-to-telomere genomes and pan-genomes for a deeper understanding of plant terrestrialization and the future directions of integrating genomic data with biological experiments for deciphering the function and origin of charophyte genes.

Biological small molecules, also known as monomeric compounds with relatively low molecular weight found in organisms, encompass a wide array of substances in plants, such as ions, plant hormones and metabolites. Studying the dynamic fluctuations of these small molecules in plants is crucial for analyzing their corresponding physiological functions, regulatory networks, and enhancing the precision of botanical research. Genetically encoded fluorescent biosensors/probes utilizing Förster resonance energy transfer (FRET) technology serves as a valuable tool for real-time monitoring of these small molecules within living organisms. These FRET biosensors/probes allow for the non-invasive visualization of specific small molecule concentrations, providing detailed information at a high resolution. Because of these unique advantages, this technique has been extensively applied in various research fields, including plant physiology, developmental biology, and environmental science. This review provides a comprehensive overview of FRET sensors/probes utilized in plant research in recent years, outlines the key design concepts, and highlights their applications and advances in detecting ions, plant hormones, and metabolites. Furthermore, this review demonstrates practical technological tools and potential research directions for elucidating the functions of small biomolecules in plants.

Cyclic nucleotide-gated channels (CNGCs) are important cation channels that play pivotal roles in the regulation of growth and development, as well as in response to stresses such as cold, heat, salt, and pathogen attacks in plants. In this review, we briefly outline the classification, structure and location of CNGCs in plants, and comprehensively summarize the recent research progress on their ionic selectivity, regulatory mechanisms, and biological functions, in order to enhance our understanding of plant CNGCs and provide a reference for future research.