Yan Zeng

Background: Tartary buckwheat (Fagopyrum tataricum) serves as an excellent model for studying plant water adaptation mechanisms due to its exceptional drought tolerance. While aquaporins (AQPs) mediate the transmembrane transport of water and solutes in plants, their fine-tuned regulatory networks underlying stress resilience in Tartary buckwheat remain largely elusive. Methods: Here, we combined bioinformatics and transcriptomics to systematically identify 30 highly conserved FtAQP genes at the genome-wide level. Results: Cross-validated by qRT-PCR, our analysis revealed their distinct expression patterns across different organs. Based on our transcriptomic data, we hypothesize that FtAQP family members potentially participate in a coordinated whole-plant water management network through differential spatiotemporal expression. Specifically, the robust transcription of FtAQP8, FtAQP12, and FtAQP28 in roots is associated with the initial water uptake process. As water undergoes long-distance transport, the synergistic upregulation of FtAQP13, FtAQP17, FtAQP20, and FtAQP29 in the stem suggests a potential role in facilitating critical lateral water flow. Furthermore, during reproductive development, FtAQP27 exhibits extreme tissue specificity in floral organs, implying its possible involvement in maintaining local osmotic homeostasis. Furthermore, the promoter regions of FtAQPs are highly enriched with cis-acting elements responsive to light, abscisic acid (ABA), and cold stress, suggesting they are intimately regulated by a coupling of endogenous phytohormones and environmental cues. Conclusions: Ultimately, this study provides valuable insights into the potential molecular basis of multidimensional water regulation in Tartary buckwheat, and identifies candidate genetic targets for improving water use efficiency in dryland agriculture through the precise manipulation of aquaporins. Collectively, while these observational findings provide valuable predictive models, future in vivo experimental validations are required to confirm their exact biological functions.

Drought stress severely restricts the growth of pear trees. As a widely used drought-tolerant rootstock, Pyrus betulifolia exhibits stable growth performance; however, the molecular mechanisms underlying its drought tolerance remain to be elucidated. In this study, we investigated the molecular responses of P. betulifolia leaves to osmotic stress induced by 20% PEG-4000 using time-series RNA-seq technology. A total of 3745 differentially expressed genes were identified, with transcriptional changes peaking at 6 h, indicating a critical phase of transcriptional reprogramming during drought response. Genes associated with osmotic adjustment (e.g., P5CS) and oxidative stress responses (e.g., SOD and POD) were significantly upregulated between 6 and 12 h. Weighted gene co-expression network analysis (WGCNA) identified three distinct temporal modules and screened out NF-Y, RVE1, COL9, COL6, C2C2 zinc finger proteins, and Pseudo ARR-B as putative key regulators, whose expression patterns were validated using qRT-PCR. Collectively, these results provide a comprehensive view of the temporal transcriptional dynamics of drought response in P. betulifolia and offer valuable candidate gene resources for further functional studies and drought tolerance breeding.

C2H2-type zinc finger transcription factors play crucial roles in regulating plant growth and responses to abiotic stresses. Although pear is an economically important fruit crop with available genomic resources, the comprehensive analyses of its C2H2 gene family remain limited. In this study, we performed a genome-wide identification of C2H2 genes in pear, identifying 52 members that were unevenly distributed across 17 chromosomes. The predicted PyC2H2 proteins ranged from 343 to 1764 amino acids in length, with molecular weights between 12.4 and 62.7 kDa. Phylogenetic analysis classified these 52 PyC2H2 proteins into 10 classical clades, where genes with closer evolutionary relationships shared more similar conserved motifs. Collinearity analysis identified 37 collinear gene pairs between Arabidopsis thaliana and pear, suggesting evolutionary conservation. Promoter analysis revealed the presence of various cis-acting elements associated with hormone and stress responses, including Box 4, G-box, and GT1-motif. Additionally, the expression patterns of PyC2H2 genes differed among pear organs. These results provide valuable insights into the potential roles of PyC2H2 genes in drought stress responses and offer a foundation for future molecular breeding of drought-tolerant pear cultivars.

Fatty acid desaturase (FAD) is a rate-limiting enzyme catalyzing the biosynthesis of unsaturated fatty acids (UFAs) and participates in key physiological processes such as plant growth and development, fruit ripening, and stress responses by regulating membrane lipid composition. Using pear genome data, this study systematically identified FAD gene family members through bioinformatic analysis and characterized their drought-responsive expression patterns. Results revealed that 34 FAD family members were identified in pear, unevenly distributed across 12 chromosomes and classified into six subfamilies. Members within the same subfamily exhibited similar conserved domains and gene structures. Promoter element analysis demonstrated that pear FAD promoters contain cis-acting elements associated with plant growth and development, hormone responses, and abiotic stress responses. qRT-PCR expression profiling showed that PbrFAD23 and PbrFAD30 were significantly upregulated during the early stages of drought stress, followed by suppressed expression levels, suggesting their potential crucial regulatory roles in the initial drought response. Genome-wide identification of 34 PbrFAD family members highlighted that PbrFAD23 and PbrFAD30, with marked upregulation under early drought stress, exhibit prominent drought responsiveness. This study provides valuable resistance gene resources for molecular breeding of stress-tolerant pear varieties and establishes a theoretical foundation for functional characterization of key drought-resistant candidate genes in pear.