The key pathways for drought tolerance in Cerasus humilis were unveiled through transcriptome analysis.

Drought stress exerts a significant impact on the growth, development, and yield of fruit trees. Cerasus humilis is an endemic drought-resistant fruit tree in northern China. To elucidate the underlying mechanism of drought resistance in C. humilis, comprehensive physiological measurements and transcriptome analysis were conducted on the leaves of C. humilis subjected to 15- or 22-days of drought stress. We identified multiple GO terms and KEGG pathways associated with the drought stress response by performing GO and KEGG analysis on DEGs. Furthermore, through the prediction of transcription factors (TFs) and analysis of their expression levels, we observed differential expression patterns among most members of stress-responsive TF families as the duration of drought stress increased. WGCNA analysis was performed on the transcriptome to identify gene cluster modules that exhibited a strong correlation with the durations of drought. Subsequently, these modules underwent GO and KEGG enrichment analyses. The study revealed that the TF-mediated lignin biosynthesis pathway, along with the plant hormone signal transduction pathway, played a prominent role in responding to drought stress of C. humilis. Gene profiling analysis, qRT-PCR, and determination of phytohormone and lignin contents further supported this hypothesis. The hierarchical gene regulatory network was finally constructed based on DEGs from the aforementioned key enriched pathways to predict the gene regulatory mechanisms in response to stress for C. humilis. The findings from this study provide valuable insights into how C. humilis copes with drought stress while analyzing crucial gene pathways associated with its resistance from a TF perspective. This research is significant for the genetic breeding of economic forests.

Genome-wide identification of WD40 superfamily in Cerasus humilis and functional characteristics of ChTTG1.

The WD40 superfamily plays an important role in a wide range of developmental and physiological processes. It is a large gene family in eukaryotes. Unfortunately, the research on the WD40 superfamily genes in Cerasus humilis has not been reported. 198 ChWD40s were identified and analyzed in the present study, along with evolutionary relationships, gene structure, chromosome distribution, and collinearity. Then, 5 pairs of tandem duplication and 17 pairs of segmental duplication were found. Based on RNA-Seq data analysis, we screened 31 candidate genes whose expression was up-regulated during the four developmental stages of fruit peel. In addition, we also demonstrated that ChWD40-140, namely ChTTG1, located in the nucleus, cytoplasm, and cytomembrane, has transcriptional activation activity and can form homodimers. ChTTG1 is involved in anthocyanin biosynthesis through heterologous overexpression in Arabidopsis. These research results provide a reference for a comprehensive analysis of the functions of WD40 in the future.

Integrated Analysis of the Metabolome and Transcriptome on Anthocyanin Biosynthesis in Four Developmental Stages of Cerasus humilis Peel Coloration.

Cerasus humilis is a unique dwarf shrub and fruit color is an important trait in the species. In this study, we evaluated the transcriptomic and metabolomic profiles of the plant at different developmental stages to elucidate the mechanism underlying color formation. In a metabolomics analysis, 16 anthocyanin components were identified at four developmental stages, and high levels of cyanidin O-syringic acid and pelargonidin 3-O-beta-d-glucoside (callitephin chloride) were correlated with the reddening of the fruit peel. A co-expression analysis revealed that ANS and UFGT play key roles in pigmentation (PCC > 0.82). Additionally, transcriptome data showed that most anthocyanin biosynthetic genes and two MYB transcription factors were significantly up-regulated. QRT-PCR results for these differentially expressed genes were generally consistent with the high-throughput sequencing. Moreover, the overexpression of ChMYB1 (TRINITY_DN21536_c0_g1) in apple calli could contribute to the accumulation of anthocyanin. It was also found that UFGT (TRINITY_DN19893_c1_g5) and ChMYB1 (TRINITY_DN21536_c0_g1) have similar expression patterns. These findings provide insight into the mechanisms underlying anthocyanin accumulation and coloration during fruit peel development, providing a basis for the breeding of anthocyanin-rich C. humilis cultivars.