Sophora moorcroftiana genome analysis suggests association between sucrose metabolism and drought adaptation

IntroductionWatermelon is an annual vine of the family Cucurbitaceae. Watermelon plants produce a fruit that people love and have important nutritional and economic value. With global warming and deterioration of the ecological environment, abiotic stresses, including drought, have become important factors that impact the yield and quality of watermelon plants. Previous research on watermelon drought resistance has included analyzing homologous genes based on known drought-responsive genes and pathways in other species.MethodsHowever, identifying key pathways and genes involved in watermelon drought resistance through high-throughput omics methods is particularly important. In this study, RNA-seq and metabolomic analysis were performed on watermelon plants at five time points (0 h, 1 h, 6 h, 12 h and 24 h) before and after drought stress.ResultsTranscriptomic analysis revealed 7829 differentially expressed genes (DEGs) at the five time points. The DEGs were grouped into five clusters using the k-means clustering algorithm. The functional category for each cluster was annotated based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) database; different clusters were associated with different time points after stress. A total of 949 metabolites were divided into 10 categories, with lipids and lipid-like molecules accounting for the most metabolites. Differential expression analysis revealed 22 differentially regulated metabolites (DRMs) among the five time points. Through joint analysis of RNA-seq and metabolome data, the 6-h period was identified as the critical period for watermelon drought resistance, and the starch and sucrose metabolism, plant hormone signal transduction and photosynthesis pathways were identified as important regulatory pathways involved in watermelon drought resistance. In addition, 15 candidate genes associated with watermelon drought resistance were identified through joint RNA-seq and metabolome analysis combined with weighted correlation network analysis (WGCNA). Four of these genes encode transcription factors, including bHLH (Cla97C03G068160), MYB (Cla97C01G002440), HSP (Cla97C02G033390) and GRF (Cla97C02G042620), one key gene in the ABA pathway, SnRK2-4 (Cla97C10G186750), and the GP-2 gene (Cla97C05G105810), which is involved in the starch and sucrose metabolism pathway.DiscussionIn summary, our study provides a theoretical basis for elucidating the molecular mechanisms underlying drought resistance in watermelon plants and provides new genetic resources for the study of drought resistance in this crop.

Section: Introductionmentioning

confidence: 99%

Joint transcriptomic and metabolomic analysis provides new insights into drought resistance in watermelon (Citrullus lanatus)

Chen,

Zhong,

et al. 2024

Comparative genomics and transcriptomics analysis of the bHLH gene family indicate their roles in regulating flavonoid biosynthesis in Sophora flavescens

Liu,

Lu,

Song

et al. 2024

The basic helix-loop-helix (bHLH) transcription factors play crucial roles in various processes, such as plant development, secondary metabolism, and response to biotic/abiotic stresses. Sophora flavescens is a widely used traditional herbal medicine in clinical practice, known for its abundant flavonoids as the main active compounds. However, there has been no comprehensive analysis of S. flavescens bHLH (SfbHLH) gene family reported currently. In this study, we identified 167 SfbHLH genes and classified them into 23 subfamilies based on comparative genomics and phylogenetic analysis. Furthermore, widespread duplications significantly contributed to the expansion of SfbHLH family. Notably, SfbHLH042 was found to occupy a central position in the bHLH protein-protein interaction network. Transcriptome analysis of four tissues (leaf, stem, root and flower) revealed that most SfbHLH genes exhibited high expression levels exclusively in specific tissues of S. flavescens. The integrated analysis of transcriptomics and metabolomics during pod development stages revealed that SfbHLH042 may play a central role in connecting SfbHLH genes, flavonoids, and key enzymes involved in the biosynthesis pathway. Moreover, we also checked the expression of 8 SfbHLH genes using RT-qPCR analysis to realize the expression profiles of these genes among various tissues at different cultivated periods and root development. Our study would aid to understand the phylogeny and expression profile of SfbHLH family genes, and provide a promising candidate gene, SfbHLH042, for regulating the biosynthesis of flavonoids in S. flavescens.

Genome-wide identification and expression analysis of the WRKY gene family in Sophora flavescens during tissue development and salt stress

Li,

Wang,

et al. 2024

Sophora flavescens is a traditional Chinese medicinal herb rich in various bioactive secondary metabolites, such as alkaloids and flavonoids, and exhibits remarkable resistance to abiotic stress. The WRKY transcription factor (TF) family is one of the largest plant-specific TF families and plays a crucial role in plant growth, development, and responses to abiotic stress. However, a comprehensive genome-wide analysis of the WRKY gene family in S. flavescens has not yet been conducted. In this study, we identified 69 SfWRKY genes from the S. flavescens genome and classified them into seven distinct subfamilies based on phylogenetic analysis. Transposed duplications and dispersed duplications were found to be the primary driving forces behind the expansion of the SfWRKY family. Additionally, several cis-acting elements related to the stress response and hormone signaling were discovered within the promoter regions of SfWRKYs. Transcriptomic analyses across five tissues (leaves, flowers, pods, roots, and stems) revealed that genes exhibiting high expression levels in specific tissues generally showed high expression across all the examined tissues. Coexpression network constructed based on metabolomic and transcriptomic analyses of root and pod development indicated that SfWRKY29 may play a significant role in regulating the biosynthesis of secondary metabolites during tissue development. The RT-qPCR results of gene expression analysis revealed that several SfWRKY genes were significantly induced in response to the accumulation of secondary metabolites or salt stress. Our study systematically analyzed WRKY TFs in S. flavescens, which provides valuable reference data for further studies on the key roles of SfWRKY genes in growth development as well as their responses under salt stress conditions.