Transcriptome Analysis Reveals the Role of GA3 in Regulating the Asynchronism of Floral Bud Differentiation and Development in Heterodichogamous Cyclocarya paliurus (Batal.) Iljinskaja

Abstract

Cyclocarya paliurus is an important medical plant owing to the diverse bioactive compounds in its leaves. However, the heterodichogamy with female and male functions segregation within protandry (PA) or protogyny (PG) may greatly affect seed quality and its plantations for medicinal use. To speculate on the factor playing the dominant role in regulating heterodichogamy in C. paliurus, based on phenotypic observations, our study performed a multi comparison transcriptome analysis on female and male buds (PG and PA types) using RNA-seq. For the female and male bud comparisons, a total of 6753 differentially expressed genes (DEGs) were detected. In addition, functional analysis revealed that these DEGs were significantly enriched in floral development, hormone, and GA-related pathways. As the dominant hormones responsible for floral differentiation and development, gibberellins (GAs) in floral buds from PG and PA types were quantified using HPLC-MS. Among the tested GAs, GA3 positively regulated the physiological differentiation (S0) and germination (S2) of floral buds. The dynamic changes of GA3 content and floral morphological features were consistent with the expression levels of GA-related genes. Divergences of GA3 contents at S0 triggered the asynchronism of physiological differentiation between male and female buds of intramorphs (PA-M vs. PA-F and PG-F vs. PG-M). A significant difference in GA3 content enlarged this asynchronism at S2. Thus, we speculate that GA3 plays the dominant role in the formation of heterodichogamy in C. paliurus. Meanwhile, the expression patterns of GA-related DEGs, including CPS, KO, GA20ox, GA2OX, GID1, and DELLA genes, which play central roles in regulating flower development, coincided with heterodichogamous characteristics. These results support our speculations well, which should be further confirmed.

Genome-wide identification and comparative analysis of DNA methyltransferase and demethylase gene families in two ploidy Cyclocarya paliurus and their potential function in heterodichogamy

“…To investigate the potential role of CpC5-MTases and CpdMTases in heterodichogamy, based on previous research results [ 17 , 23 , 30 ], correlation analysis was performed on the differential genes in the lowering process of PA and PG. Figure 8 illustrated some genes that may play roles in heterodichogamy, such as ERFs , Trihelix-1 , and GA synthesis genes.…”

“…In C. paliurus , Qu et al [ 23 ] found that GA 3 positively regulated the physiological differentiation and germination of floral buds (S2), and GA-related DEGs play central roles in regulating flower development. In addition, Meijón et al [ 43 ] detected that global DNA methylation in azalea treated with a GA biosynthesis inhibitor during the floral transition could promote flowering.…”

“…Moreover, plant hormones can alter DNA methylation status in specific and redundant ways [ 22 ]. Previous research has indicated that gibberellin, especially GA 3 , plays an important role in asynchronous floral development in heterodichogamous C. paliurus [ 23 ]. However, the regulatory mechanism of DNA methylation in asynchronous floral differentiation and development in heterodichogamous C. paliurus is still unclear.…”

Genome-wide identification of bHLH transcription factors and their response to salt stress in Cyclocarya paliurus

“…In general, the function of a given gene can be inferred from its homologous genes ( Yue et al., 2016 ; Qu et al., 2022 ). Therefore, Arabidopsis orthologs were used to predict the regulatory network of these three candidate genes ( CpbHLH36/68/146 ) in this study.…”

Genome-wide identification and analysis of bZIP gene family reveal their roles under salt stress in Suaeda australis

“…18S ribosomal RNA as an internal control was carried out. The methods for calculating relative gene expression were introduced by previous study [44].…”