Chionanthus retusus, an arbor tree of the Oleaceae family, is an ecologically and economically valuable ornamental plant for its remarkable adaptability in landscaping. During C. retusus breeding, we observed diverse floral shapes; however, no available genome for C. retusus has hindered the widespread identification of genes related to flower morphology. Thus, a de novo telomere-to-telomere (T2T) gap-free genome was generated. The assembly, incorporating high-coverage and long-read sequencing data, successfully yielded two complete haplotypes (687 and 683 Mb). The genome encompasses 42 864 predicted protein-coding genes, with all 46 telomeres and 23 centromeres in one haplotype. Whole-genome duplication analysis revealed that C. retusus underwent one fewer event of whole-genome duplication after differentiation compared to other species in the Oleaceae family. Furthermore, flower vein diversity was the main reason for the differences in floral shapes. Auxin-related genes were responsible for petal shape formation on genome-based transcriptome analysis. Specifically, the removal and retention of the first intron in CrAUX/IAA20 resulted in the production of two transcripts, and the differences in the expression levels of CrAUX/IAA20 resulted in the variations of flower veins. Compared to transcripts lacking the first intron, transcripts with intron retention caused more severe decreases in the number and length of flower veins in transgenic Arabidopsis thaliana. Our findings will deepen our understanding of flower morphology development and provide important theoretical support for the cultivation of Oleaceae.

Woody bamboos (Bambusoideae) are renowned for its polyploidy and rare flowering. Bambusa odashimae is one of the bamboo species with the highest chromosome count (104) in the subfamily and has the highest heterozygosity of all sequenced bamboo genomes so far. Compared with other bamboo species, it can efficiently utilize exogenous hormones to regulate in vitro flowering, providing valuable insights into the hormonal regulation of bamboo flowering. Here, we generated the haplotype-resolved genome assembly of B. odashimae, despite the complexity and high chromosome number, supplemented by thirty-three transcriptomes from eleven developmental periods using a tissue culture system. The assembled genome can be divided into Haplotype I, Haplotype II, and Haplotype III, each containing A, B, and C subgenomes. Haplotype I may be derived from Dendrocalamus whereas Haplotypes II and III are closely related to Bambusa, indicating that B. odashimae has an origin involving both intergeneric and interspecific hybridizations. The high heterozygosity renders the possibility to detect abundant allele-specific expression (ASE), with ASE genes enriched in cytokinin-related pathways, likely associated with efficient cytokinin-promoted flowering. Notably, we found that the CONSTANS (CO) genes were potentially key regulators of in vitro flowering in B. odashimae. Overall, based on the in vitro system combined with a high-quality reference genome, our study provides critical insights into the origin of this nonaploid bamboo and links hybridization and in vitro flowering in bamboos.

Soluble sugars are not only an important contributor to fruit quality, but also serve as the osmotic regulators in response to abiotic stresses. Early drought stress promotes sugar accumulation, while specific sugar transporters govern the cellular distribution of the sugars. Here, we show that apple plantlets accumulate soluble sugars in leaf tissues under drought stress. Transcriptional profiling of stressed and control plantlets revealed differential expression of several plasma membrane—or vacuolar membrane-localized sugar transporter genes. Among these, four previously identified vacuolar sugar transporter (VST) genes (MdERDL6-1, MdERDL6-2, MdTST1, and MdTST2 ) showed higher expression under drought, suggesting their roles in response to drought stress. Promoter cis -elements analyses, yeast one-hybrid, and dual-luciferase tests confirmed that the drought-induced transcription factor MdDREB2A could promote the expression of MdERDL6-1/ − 2 and MdTST1/2 by binding to their promoter regions. Moreover, overexpressing of each of these four MdVSTs alone in transgenic apple or Arabidopsis plants accumulated more soluble sugars and abscisic acid (ABA), and enhanced drought resistance. Furthermore, apple plants overexpressing MdERDL6-1 also showed reduced water potential, facilitated stomatal closure, and reactive oxygen species scavenging under drought conditions compared to control plants. Overall, our results suggest a potential strategy to enhance drought resistance and sugar accumulation in fruits through manipulating the genes involved in vacuolar sugar transport.

De novo genes can evolve “from scratch” from noncoding sequences, acquiring novel functions in organisms and integrating into regulatory networks during evolution to drive innovations in important phenotypes and traits. However, identifying de novo genes is challenging, as it requires high-quality genomes from closely related species. According to the comparison with nine closely related Prunus genomes, we determined at least 178 de novo genes in P. persica “baifeng”. The distinct differences were observed between de novo and conserved genes in gene characteristics and expression patterns. Gene ontology enrichment analysis suggested that Type I de novo genes originated from sequences related to plastid modification functions, while Type II genes were inferred to have derived from sequences related to reproductive functions. Finally, transcriptome sequencing across different tissues and developmental stages suggested that de novo genes have been evolutionarily recruited into existing regulatory networks, playing important roles in plant growth and development, which was also supported by WGCNA analysis and quantitative trait loci data. This study lays the groundwork for future research on the origins and functions of genes in Prunus and related taxa.

The target of rapamycin (TOR) kinase is a central signaling hub that plays a crucial role in precisely orchestrating plant growth, development, and stress responses. This suggests that TOR is intricately involved in maintaining the balance between plant growth and stress responses. Nevertheless, despite the observed effects, the specific mechanisms through which TOR operates in these processes remain obscure. In this study, we investigated how the tomato (Solanum lycopersicum) TOR (SlTOR) affects plant growth and cold responses. We demonstrated that SlTOR inhibition transcriptionally primes cold stress responses, consequently enhancing tomato cold tolerance. A widely targeted metabolomics analysis revealed the disruption of amino acid metabolism homeostasis under cold stress upon SlTOR inhibition, which led to the accumulation of two important cryoprotective metabolites: salicylic acid (SA) and putrescine (Put). Next, we discovered SlPGH1 (2-PHOSPHO-D-GLYCERATE HYDRO-LYASE 1) as a direct substrate of SlTOR. Inhibiting SlTOR led to increased SlCBF1 (C-REPEAT-BINDING FACTOR 1) expression via SlPGH1, potentially triggering the activation of cold-responsive genes and subsequent metabolic alterations. Our study provides a mechanistic framework that elucidates how SlTOR modulates amino acid-related metabolism to enhance tomato cold tolerance, which sheds light on the complex interplay between growth and stress responses orchestrated by TOR.

Graft compatibility is the capacity of two plants to form cohesive vascular connections. Tomato and pepper are incompatible graft partners; however, the underlying cause of graft rejection between these two species remains unknown. We diagnosed graft incompatibility between tomato and diverse pepper varieties based on weakened biophysical stability, decreased growth, and persistent cell death using viability stains. Transcriptomic analysis of the junction was performed using RNA sequencing, and molecular signatures for incompatible graft response were characterized based on meta-transcriptomic comparisons with other biotic processes. We show that tomato is broadly incompatible with diverse pepper cultivars. These incompatible graft partners activate prolonged transcriptional changes that are highly enriched for defense processes. Amongst these processes was broad nucleotide-binding and leucine-rich repeat receptors (NLR) upregulation and genetic signatures indicative of an immune response. Using transcriptomic datasets for a variety of biotic stress treatments, we identified a significant overlap in the genetic profile of incompatible grafting and plant parasitism. In addition, we found over 1000 genes that are uniquely upregulated in incompatible grafts. Based on NLR overactivity, DNA damage, and prolonged cell death, we hypothesize that tomato and pepper graft incompatibility is characterized by an immune response that triggers cell death which interferes with junction formation.

Illuminating the phenotype-genotype black box under complex traits is an ambitious goal for researchers. The generation of temporally or spatially phenotypic data today has far outpaced its interpretation, due to their highly dynamic nature depending on the environment and developmental stages. Here, we propose an integrated enviro-pheno-geno functional approach to pinpoint the major challenges of decomposing physiological traits. The strategy first features high-throughput functional physiological phenotyping (FPP) to efficiently acquire phenotypic and environmental data. It then features functional mapping (FM) and the extended systems mapping (SM) to tackle trait dynamics. FM, by modeling traits as continuous functions, can increase the power and efficiency in dissecting the spatiotemporal effects of QTLs. SM could enable reconstruction of a genotype-phenotype map from developmental pathways. We present a recent case study that combines FPP and SM to dissect complex physiological traits. This integrated approach will be an important engine to drive the translation of phenomic big data into genetic gain.

Ginseng (Panax ginseng ) renowned as the king of medicinal plants. Ginseng grows slowly under shade conditions, requiring at least 4 years to produce a limited number of seeds. Molecular breeding of ginseng faces challenges due to its the tetraploid genome and the absence of an efficient molecular marker system. To overcome these obstacles, we adopted genotyping-by-sequencing to delve into genetic mapping and survey genetic diversity. We constructed a comprehensive genetic map comprising 24 linkage groups, each corresponding to one of the 24 chromosomes in the ginseng genome, based on 1216 nonredundant SNPs obtained from an F2 mapping population. Additionally, 431 103 SNPs were identified from 119 diverse ginseng genotypes. From these, 192 informative subgenome-specific single copy SNPs were selected to develop a SNP chip. The SNP chip was used to genotype a large ginseng collection, encompassing registered cultivars, breeding lines, wild-simulated ginseng, and wild ginseng from various countries and regions. We evaluated the utility of the assay for molecular breeding with 919 ginseng genotypes. This breeder-friendly SNP chip promises versatility, enabling purity assessments of seeds and products, the authentication of species and cultivars, and the determination of homozygosity and homogeneity rates for breeding lines. Genotype data for 1200 ginseng genotypes are now stored in our database. This SNP chip lays the foundation for a molecular breeding in ginseng and will facilitate the breeding process in this medicinal crop.

Pea occupy a key position in modern biogenetics, playing multifaceted roles as food, vegetable, fodder, and green manure. However, due to the complex nature of its genome and the prolonged unveiling of high-quality genetic maps, research into the molecular mechanisms underlying pea development and stress responses has been significantly delayed. Furthermore, the exploration of its epigenetic modification profiles and associated regulatory mechanisms remains uncharted. This research conducted a comprehensive investigation of four specific histone marks, namely H3K4me3, H3K27me3, H3K9ac, and H3K9me2, and the transcriptome in pea under normal conditions, and established a global map of genome-wide regulatory elements, chromatin states, and dynamics based on these major modifications. Our analysis identified epigenomic signals across ∼82.6% of the genome. Each modification exhibits distinct enrichment patterns: H3K4me3 is predominantly associated with the gibberellin response pathway, H3K27me3 is primarily associated with auxin and ethylene responses, and H3K9ac is primarily associated with negative regulatory stimulus responses. We also identified a novel bivalent chromatin state (H3K9ac-H3K27me3) in pea, which is related to their development and stress response. Additionally, we unveil that these histone modifications synergistically regulate metabolic-related genes, influencing metabolite production under salt stress conditions. Our findings offer a panoramic view of the major histone modifications in pea, elucidate their interplay, and highlight their transcriptional regulatory roles during salt stress.

Garlic is a widely utilized condiment and health product. However, garlic bulbs are prone to quality deterioration resulting in decrease of economic value during postharvest. In this study, the storability of 501 garlic accessions worldwide was evaluated based on the examination of decay index (DI), decay rate, sprouting rate, and bud-to-clove ratio in two consecutive years. The DI was employed as a primary index for evaluating the storability of garlic. Among these garlic, 43 accessions exhibited strong storability with DI of 0%-5%. Phenotypic and cytological observations revealed that strong storability accessions displayed delayed sprouting and decay, a slow rate of nutrient transfer to vascular bundles. Through genome-wide association study (GWAS), 234 single-nucleotide polymorphism loci (SNPs) were associated with the storability, which were located in or near 401 genes, which were annotated the functions of resistance, storage substances transport, etc. A total of 44 genes were screened using selective sweep analysis. Transcriptomic analysis was performed at four periods after storage in the 8N035 accession with strong storability and 8N258 accession with weak storability. Compared with 8N035, the upregulated genes in the 8N258 were enriched in photosynthesis and stress response, whereas the downregulated genes were enriched in response of biotic and abiotic stress and defense response. A co-expression network and GWAS identified three hub genes as key regulatory genes. Conjoint analysis of GWAS, selective sweep, and transcriptomic analysis identified 21 important candidate genes. These findings provided excellent resources with storability and vital candidate genes regulating storability for biological breeding of garlic.

Safflower, an economic crop, is renowned for its flowers, which are widely used in medicines for treating cardiovascular and cerebrovascular diseases and in dyes for food and industry. The utility of safflower depends on its flavonoid glycosides. Therefore, the biosynthesis of safflower flavonoid glycosides has been a focus of attention, but the present mechanisms remain poorly understood. This study aims to identify functional genes associated with flavonoid glycoside biosynthesis in safflower through a comprehensive approach that integrates whole-genome screen and multi-omics correlation studies. CYP and UGT are two crucial genes families involved in flavonoid glycoside biosynthesis. We have screened 264 CYP genes and 140 UGT genes in the genome of safflower and conducted analyzes including phylogenetic relationships, conserved motifs, gene structures, cis-acting elements, and chromosome mapping, which provided extensive and comprehensive data on the CYP and UGT gene families. Integration of phenotype and metabolic data from safflower different tissues helped narrow down the screening by confirming that HSYA is synthesized only in flowers. Based on the gene expression patterns and phylogenetic analysis, CtOGT1 was ultimately identified, which could catalyze the generation of glycosides using various flavonoid substrates and exhibited strong substrate affinity. Moreover, molecular docking studies elucidated CtOGT1’s highly active intrinsic mechanism. In conclusion, this study effectively identified genes responsible for flavonoid glycoside biosynthesis in safflower through the integration of whole-genome screen and multi-omics analysis, established a comprehensive foundation of data, methodology, and experimental evidence for further elucidating the pathways of safflower flavonoid glycoside biosynthesis.

Increasing agricultural losses caused by insect infestations are a significant problem, so it is important to generate pest-resistant crop varieties to address this issue. Several reviews have examined aphid-plant interactions from an entomological perspective. However, few have specifically focused on plant resistance mechanisms to aphids and their applications in breeding for aphid resistance. In this review, we first outline the types of resistance to aphids in plants, namely antixenosis, tolerance (cell wall lignification, resistance proteins), and antibiosis, and we discuss strategies based on each of these resistance mechanisms to generate plant varieties with improved resistance. We then outline research on the complex interactions amongst plants, viruses, and aphids, and discuss how aspects of these interactions can be exploited to improve aphid resistance. A deeper understanding of the epigenetic mechanisms related to induced resistance, i.e. the phenomenon where plants become more resistant to a stress they have encountered previously, may allow for its exploitation in breeding for aphid resistance. Wild relatives of crop plants serve as important sources of resistance traits. Genes related to these traits can be introduced into cultivated crop varieties by breeding or genetic modification, and de novo domestication of wild varieties can be used to exploit multiple excellent characteristics, including aphid resistance. Finally, we discuss the use of molecular design breeding, genomic data, and gene editing to generate new aphid-resistant, high-quality crop varieties.