Fangfang Cai

Background/Objectives: The coordination of flowering and dormancy represents a fundamental adaptive strategy for perennial plant survival. Recent studies have demonstrated that AIL1 homologs act as integrators of short-day signals, playing pivotal roles in seasonal growth cessation and dormancy regulation in poplar. Despite these advances, whether AIL1-mediated regulatory mechanisms are conserved in Platanus acerifolia, a species with distinct phylogenetic and ecological characteristics, remains an open question. Methods: In this study, two AIL1 homologs, PaAIL1a and PaAIL1b, were isolated from P. acerifolia. Their biological functions were systematically investigated through sequence analysis, spatiotemporal expression profiling, environmental stress treatments, yeast one-hybrid assays, and luciferase (LUC) transient expression assays. Results: PaAIL1s (PaAIL1a and PaAIL1b) exhibited ubiquitous expression across diverse tissues and organs, functioning as mediators of photoperiod and temperature signaling to orchestrate bud dormancy regulation. Interaction and activation assays placed these factors downstream of PaFUL proteins. While displaying functional redundancy in dormancy induction and floral development, the paralogs underwent distinct subfunctionalization: PaAIL1a specifically regulated flowering initiation and dormancy release, whereas PaAIL1b acted predominantly during the ecodormancy phase. Conclusions: These results establish PaAIL1 genes as critical integrators of environmental signals and developmental programs, governing seasonal growth dynamics in this species.

Azaleas (Rhododendron simsii) are popular ornamental woody plants known for their bright colors; however, very limited studies have been reported on the process of flower petal pigmentation. In this study, we found significant differences in the anthocyanin contents of petals from different colored azaleas, and the results of quantitative real-time PCR indicated that the R2R3 MYB genes, RsMYB12, RsMYB90, and RsMYB123, showed significant expression changes during the petal coloration in azalea petals; therefore, we hypothesized that RsMYB12, RsMYB90, and RsMYB123 might involve in the coloring process of azalea petals by regulating anthocyanin synthesis. This work provides insights into the underlying mechanisms of petal pigmentation in R. simsii and provides candidate genes for flower color breeding of azaleas and other ornamental flowers.

The B-BOX (BBX) gene family is widely distributed in animals and plants and is involved in the regulation of their growth and development. In plants, BBX genes play important roles in hormone signaling, biotic and abiotic stress, light-regulated photomorphogenesis, flowering, shade response, and pigment accumulation. However, there has been no systematic analysis of the BBX family in Platanus × acerifolia. In this study, we identified 39 BBX genes from the P. × acerifolia genome, and used TBtools, MEGA, MEME, NCBI CCD, PLANTCARE and other tools for gene collinearity analysis, phylogenetic analysis, gene structure, conserved domain analysis, and promoter cis-element analysis, and used the qRT-PCR and transcriptome data for analyzing expression pattern of the PaBBX genes. Collinearity analysis indicated segmental duplication was the main driver of the BBX family in P. × acerifolia, and phylogenetic analysis showed that the PaBBX family was divided into five subfamilies: I, II, III, IV and V. Gene structure analysis showed that some PaBBX genes contained super-long introns that may regulate their own expression. Moreover, the promoter of PaBBX genes contained a significant number of cis-acting elements that are associated with plant growth and development, as well as hormone and stress responses. The qRT-PCR results and transcriptome data indicated that certain PaBBX genes exhibited tissue-specific and stage-specific expression patterns, suggesting that these genes may have distinct regulatory roles in P. × acerifolia growth and development. In addition, some PaBBX genes were regularly expressed during the annual growth of P. × acerifolia, corresponding to different stages of flower transition, dormancy, and bud break, indicating that these genes may be involved in the regulation of flowering and/or dormancy of P. × acerifolia. This article provided new ideas for the study of dormancy regulation and annual growth patterns in perennial deciduous plants.

Leucoanthocyanidin reductase (LAR) is the critical enzyme in the synthesis pathway of proanthocyanidins, which are the primary pigments in brown cotton fibers. Our previous study has revealed significant differences in the expression levels of GhLAR1 between white and brown cotton fibers at 10 DPA. In this work, the expression pattern of the GhLAR1 gene was further studied, and the promoter of GhLAR1 (1780 bp) was isolated and characterized. Bioinformatic analysis indicated that GhLAR1 promoter contained many known light response elements and several defenses related to transcriptional factor-binding boxes, which may partially explain the response of the GhLAR1 to temperature, NaCl, and PEG treatments. Furthermore, GhLAR1 was preferentially and strongly expressed in fibers and flowers of cotton, and the expression levels in all tested tissues (especially fibers) of brown cotton were significantly higher than those in white cotton. Consistent with the expression analysis, the GhLAR1 promoter mainly drove GUS expression in epidermal trichomes and floral organs.

Cotton Verticillium wilt, caused by the notorious fungal phytopathogen Verticillium dahliae (V. dahliae), is a destructive soil-borne vascular disease and severely decreases cotton yield and quality worldwide. Transcriptional and post-transcriptional regulation of genes responsive to V. dahliae are crucial for V. dahliae tolerance in plants. However, the specific microRNAs (miRNAs) and the miRNA/target gene crosstalk involved in cotton resistance to Verticillium wilt remain largely limited. To investigate the roles of regulatory RNAs under V. dahliae induction in upland cotton, mRNA and small RNA libraries were constructed from mocked and infected roots of two upland cotton cultivars with the V. dahliae-sensitive cultivar Jimian 11 (J11) and the V. dahliae-tolerant cultivar Zhongzhimian 2 (Z2). A comparative transcriptome analysis revealed 8330 transcripts were differentially expressed under V. dahliae stress and associated with several specific biological processes. Moreover, small RNA sequencing identified a total of 383 miRNAs, including 330 unique conserved miRNAs and 53 novel miRNAs. Analysis of the regulatory network involved in the response to V. dahliae stress revealed 31 differentially expressed miRNA–mRNA pairs, and the up-regulation of GhmiR395 and down-regulation of GhmiR165 were possibly involved in the response to V. dahliae by regulating sulfur assimilation through the GhmiR395-APS1/3 module and the establishment of the vascular pattern and secondary cell wall formation through GhmiR165-REV module, respectively. The integrative analysis of mRNA and miRNA expression profiles from upland cotton lays the foundation for further investigation of regulatory mechanisms of resistance to Verticillium wilt in cotton and other crops.