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The GRAS gene family, responsible for encoding transcription factors, serves pivotal functions in plant development, growth, and responses to stress. The exploration of the GRAS gene family within the Orchidaceae has been comparatively limited, despite its identification and functional description in various plant species. This study aimed to conduct a thorough examination of the GRAS gene family in Cymbidum goeringii, focusing on its physicochemical attributes, phylogenetic associations, gene structure, cis-acting elements, and expression profiles under heat stress. The results show that a total of 54 CgGRASs were pinpointed from the genome repository and categorized into ten subfamilies via phylogenetic associations. Assessment of gene sequence and structure disclosed the prevalent existence of the VHIID domain in most CgGRASs, with around 57.41% (31/54) CgGRASs lacking introns. The Ka/Ks ratios of all CgGRASs were below one, indicating purifying selection across all CgGRASs. Examination of cis-acting elements unveiled the presence of numerous elements linked to light response, plant hormone signaling, and stress responsiveness. Furthermore, CgGRAS5 contained the highest quantity of cis-acting elements linked to stress response. Experimental results from RT-qPCR demonstrated notable variations in the expression levels of eight CgGRASs after heat stress conditions, particularly within the LAS, HAM, and SCL4/7 subfamilies. In conclusion, this study revealed the expression pattern of CgGRASs under heat stress, providing reference for further exploration into the roles of CgGRAS transcription factors in stress adaptation. [ABSTRACT FROM AUTHOR]

Cymbidium sinense, a type of orchid plant, is more drought-resistant and ornamental than other terrestrial orchids. Research has shown that many members of the NUCLEAR FACTOR Y (NF-Y) transcription factor family are responsive to plant growth, development, and abiotic stress. However, the mechanism of the NF-Y gene family's response to abiotic stress in orchids has not yet been reported. In this study, phylogenetic analysis allowed for 27 CsNF-Y genes to be identified (5 CsNF-YAs, 9 CsNF-YBs, and 13 CsNF-YC subunits), and the CsNF-Ys were homologous to those in Arabidopsis and Oryza. Protein structure analysis revealed that different subfamilies contained different motifs, but all of them contained Motif 2. Secondary and tertiary protein structure analysis indicated that the CsNF-YB and CsNF-YC subfamilies had a high content of alpha helix structures. Cis-element analysis showed that elements related to drought stress were mainly concentrated in the CsNF-YB and CsNF-YC subfamilies, with CsNF-YB3 and CsNF-YC12 having the highest content. The results of a transcriptome analysis showed that there was a trend of downregulation of almost all CsNF-Ys in leaves under drought stress, while in roots, most members of the CsNF-YB subfamily showed a trend of upregulation. Additionally, seven genes were selected for real-time reverse transcription quantitative PCR (qRT-PCR) experiments. The results were generally consistent with those of the transcriptome analysis. The regulatory roles of CsNF-YB 1, 2, and 4 were particularly evident in the roots. The findings of our study may make a great contribution to the understanding of the role of CsNF-Ys in stress-related metabolic processes. [ABSTRACT FROM AUTHOR]

SPL transcription factors regulate important processes such as plant growth and development, metabolic regulation, and abiotic stress. They play crucial roles in the development of flower organs. However, little is known about the characteristics and functions of the SPLs in the Orchidaceae. In this study, Cymbidium goeringii Rchb. f., Dendrobium chrysotoxum Lindl., and Gastrodia elata BI. were used as research objects. The SPL gene family of these orchids was analyzed on a genome-wide scale, and their physicochemical properties, phylogenetic relationships, gene structures, and expression patterns were studied. Transcriptome and qRT-PCR methods were combined to investigate the regulatory effect of SPLs on the development of flower organs during the flowering process (bud, initial bloom, and full bloom). This study identifies a total of 43 SPLs from C. goeringii (16), D. chrysotoxum (17), and G. elata (10) and divides them into eight subfamilies according to the phylogenetic tree. Most SPL proteins contained conserved SBP domains and complex gene structures; half of the genes had introns longer than 10 kb. The largest number and variety of cis-acting elements associated with light reactions were enriched, accounting for about 45% of the total (444/985); 13/43 SPLs contain response elements of miRNA156. GO enrichment analysis showed that the functions of most SPLs were mainly enriched in the development of plant flower organs and stems. In addition, expression patterns and qRT-PCR analysis suggested the involvement of SPL genes in the regulation of flower organ development in orchids. There was little change in the expression of the CgoSPL in C. goeringii, but DchSPL9 and GelSPL2 showed significant expression during the flowering process of D. chrysotoxum and G. elata, respectively. In summary, this paper provides a reference for exploring the regulation of the SPL gene family in orchids. [ABSTRACT FROM AUTHOR]