Ornamental plants can generate higher economic value per unit area compared to traditional crops. Enhancing market share in the flower industry relies on cultivating varieties with exceptional ornamental traits. Petal size, a critical factor influencing flower shape and ornamental appeal, is a primary focus for horticultural breeding selection. In this article, we review recent advances in understanding the regulation of petal size in ornamental plants through analyzing various patterns of cell division and expansion underlying petal growth and the genes involved in the related regulatory paradigms. We further highlight the intricate network of petal size control affected by multiple phytohormones and discuss several open questions and strategies for breeding ornamental plants with desired petal size traits based on current findings.

The TIFY gene family (formerly known as the zinc finger proteins expressed in inflorescence meristem (ZIM) family) not only functions in plant defense responses but also are widely involved in regulating plant growth and development. However, the identification and functional analysis of TIFY proteins remain unexplored in Orchidaceae. Here, we identified 19 putative TIFY genes in the Phalaenopsis aphrodite genome. The phylogenetic tree classified them into four subfamilies: 14 members from JAZ, 3 members from ZML, and 1 each from PPD and TIFY. Sequence analysis revealed that all Phalaenopsis TIFY proteins contained a TIFY domain. Exon–intron analysis showed that the intron number and length of Phalaenopsis TIFY genes varied, whereas the same subfamily and subgroup genes had similar exon or intron numbers and distributions. The most abundant cis-elements in the promoter regions of the 19 TIFY genes were associated with light responsiveness, followed by MeJA and ABA, indicating their potential regulation by light and phytohormones. The 13 candidate TIFY genes screened from the transcriptome data exhibited two types of expression trends, suggesting their different roles in cell proliferation and cell expansion of floral organ growth during Phalaenopsis flower opening. Overall, this study serves as a background for investigating the underlying roles of TIFY genes in floral organ growth in Phalaenopsis.

Fusarium wilt of Phalaenopsis spp., caused by Fusarium species, is a major soil-borne disease that severely threatens the yield and ornamental quality of Phalaenopsis. Endophytic fungi can serve as natural biocontrol agents against soil-borne pathogens and have potential applications in biological control. In this study, a pathogenic isolate, HT-1, was obtained from Fusarium-wilted Phalaenopsis plants, and its pathogenicity was confirmed through inoculation assays on detached leaves and intact plants. Morphological observations, together with internal transcribed spacer (ITS) and translation elongation factor 1-α (TEF-1α) sequence analyses, identified HT-1 as Fusarium proliferatum. Seven endophytic fungi with strong antagonism against F. proliferatum were screened using a dual-culture assay. All seven isolates consistently inhibited five representative plant pathogens in vitro, showing broad-spectrum and promising biocontrol potential. Detached leaf inoculation assays showed that both Trichoderma virens and Trichoderma asperellum significantly reduced lesion area and disease severity caused by F. proliferatum, indicating potential application in disease management. In summary, this study identified seven endophytic fungi from Phalaenopsis with broad-spectrum antagonistic potential against multiple plant pathogenic fungi. Meanwhile, the protective effects of T. virens and T. asperellum against F. proliferatum were preliminarily evaluated using detached leaves. These findings provide theoretical reference and fungal resources for screening candidate biocontrol strains against Phalaenopsis Fusarium wilt and related plant diseases, and lay a foundation for future studies on biocontrol mechanisms, whole-plant efficacy verification, and practical application.