Molecular Horticulture最新文献

The Corydalis genus, one of the largest within the Papaveraceae family, holds a rich diversity of medicinal resources, particularly among its tuberous species. Benzylisoquinoline alkaloids (BIAs) are primarily responsible for the medicinal properties observed in Corydalis plants. In this study, we conducted an integrated evolutionary analysis by combining whole-genome resequencing with comprehensive metabolite profiling across various Corydalis species. Guided by these initial findings, supported by local cultivation practices and an extensive literature review, we further investigated six tuberous Corydalis species: C. yanhusuo, C. decumbens, C. schanginii, C. ledebouriana, C. solida, and the newly identified C. nanchuanensis. Our results revealed conserved alkaloid profiles across these species but highlighted significant variations in key bioactive compounds. Notably, C. nanchuanensis exhibited considerably higher levels of tetrahydropalmatine compared to the commonly used medicinal species C. yanhusuo, while C. solida, originally sourced from the Netherlands, displayed elevated concentrations of corydaline, palmatine, and dehydrocorydaline. Additionally, transcriptome-metabolome correlation analyses pinpointed several critical genes involved in protopine biosynthesis, particularly emphasizing the TNMT gene family. These discoveries significantly enhance our understanding of metabolic diversity in tuberous Corydalis, providing essential insights for the exploration of novel medicinal resources and facilitating targeted genetic improvements for therapeutic use.

Fleshy Fruit (FF) ripening is regulated by multiple hormones, which can be categorized into two groups, i.e., the positive signals acting to promote FF ripening and the negative signals acting to suppress FF ripening. Ethylene (ET) and abscisic acid (ABA) are two predominant positive signals respectively controlling climacteric (CL) and non-climacteric (NC) FF ripening, whereas auxin (IAA) is the predominant negative signal controlling both FF growth and ripening. Functioning of these hormones is initiated by an alteration of the hormonal levels, which is referred to as the process of Hormonal Signal Production (HSP) in FF development and ripening. While the hormonal regulation of FF ripening has been extensively studied and reviewed, knowledge of HSP has never been summarized and discussed. The purpose of this review is to summarize and discuss the triggering mechanism of HSP. We first summarize the physiological, biochemical and molecular bases of HSP for three crucial hormones, ET, ABA, and IAA, including hormonal metabolism, transport and reciprocal regulation of HSP among different hormones, we then summarize and discuss the recent discoveries on the mechanism of cellular signal transduction of HSP. Finally, we propose several viewpoints to facilitate comprehension of the future research endeavors.

MicroRNAs are a class of endogenous small non-coding RNAs, some of which can trigger phased secondary small interfering RNA (phasiRNA) production from target genes. Mitochondrial transcription termination factors (mTERFs), mainly localized in chloroplasts and/or mitochondria, play critical roles in plant development and stress responses. We report here the identification of 63 mTERFs and a 22 nt novel miRNA (smi-miRmTERF), which directly cleave SmmTERF33 and SmmTERF45 transcripts to trigger phasiRNA biogenesis. The generated phasiRNAs could further trigger phasiRNA biogenesis from SmmTERF26 and regulated a subset of lineage-specific SmmTERFs. MIRmTERF widely existed in Nepetoideae plants and SmmTERF33 and SmmTERF45 proteins were localized in chloroplasts, mitochondria, and the cytoplasm. Smi-miRmTERF overexpression (MIRMTERF#OE) resulted in a dwarfing phenotype with severe defects in chloroplast and mitochondrial morphogenesis. Transcriptomic analysis showed up-regulation of defense-related and down-regulation of photosynthesis-related genes in MIRMTERF#OE plants. Under norflurazon and lincomycin treatments, MIRMTERF#OE plants displayed a gun phenotype, indicating the role of smi-miRmTERF in retrograde signaling. Furthermore, MIRMTERF#OE plants showed increased contents of phenolic acids, monoterpenoids, and sesquiterpenoids and reduced susceptibility to pathogenic bacteria Pst DC3000. The results suggest that smi-miRmTERF is a significant regulator of chloroplast and mitochondrial development, retrograde signaling, secondary metabolism, and immunity in S. miltiorrhiza.

The Fagaceae family, comprising over 900 species, is an essential component of Northern Hemisphere forest ecosystems. However, genomic data for tropical and subtropical genera Castanopsis and Castanea remain limited compared to the well-studied oak. Here, we present chromosome-level genome assemblies of Castanopsis carlesii and Castanea henryi, with assembled genome sizes of 927.24 Mb (N50 = 1.57 Mb) and 780.10 Mb (N50 = 1.07 Mb), respectively, and repetitive sequence contents of 45.79% and 44.88%. Comparative genomic analysis revealed that the estimated divergence time between Castanopsis and Castanea was determined to be 48.3 Mya and provided evidence that both genera experienced only one of the ancient whole genome triplication event (γ event) shared with most eudicots. The development of C. carlesii flower bracts and cupules was controlled by A- and E-class genes, suggesting that the cupules may originate from the bracts. Additionally, genes involved in sucrose and starch metabolism genes played distinct roles during C. carlesii fruit development. The amplification of the nucleotide-binding leucine-rich repeat (NLR) gene family in Fagaceae exhibited similarities, indicating that this expansion may be an adaptation to similar environmental pressures. This study provides valuable genomic resources for Asian Fagaceae and enhances our understanding of Fagaceae evolution.

Watermelon fruit flesh displays various colors. Although genetic loci underlying these variations are identified, the molecular mechanism remains elusive. Here, we assembled a chromosome-scale reference genome of an elite watermelon and developed integrated genetic maps using single nucleotide polymorphism (SNP) and structural variation markers. Several key genetic varients for fruit shape and flesh color were identified. Two variants associated with flesh color were further studied, including one copy number variant (CNV, a triplicate of 1.2 kb DNA) in the promoter region of REDUCED CHLOROPLAST COVERAGE 2 (ClREC2) and one SNP in Lycopene β-Cyclase (ClLCYB) coding region. These two variants together explained 99.7% of the flesh color variations in 314 watermelon accessions. The SNP in ClLCYB was the same as previously reported, disrupting ClLCYB function. The CNV could strongly enhance ClREC2 expression, consequently increasing the expression of carotenoid biosynthesis genes, the number of plastoglobules within chromoplasts, and carotenoid level in mature fruit flesh. Finally, we proposed a "two-switch" genetic model by integrating two major causative loci, which can explain the formation of the four main flesh colors in different watermelon accessions. These results provide new insights into the regulation of carotenoid biosynthesis and color formation in plants.