# Unravelling the Molecular Regulation Mechanisms of Slow Ripening Trait in _Prunus persica_
## 2 Results
### Hormonal Differences between Normal and Slow Ripening Phenotypes
#### 2.3.2 Geranyligeranyl Diphosphate Biosynthesis, Precursor of ABA and GA Production  
Abscisic acid and gibberellin biosynthesis pathways start with the same precursor, geranylgeranyl diphosphate (GGPP), produced by the metabolism of pyruvate and glyceraldehyde 3-phosphate (Figure 3, yellow section). Our results showed differences in all enzymes that belong to the canonical GGPP biosynthetic pathway in T7, and we observed a lower abundance of these transcripts in SR fruit. However, no differences were observed in the early developmental stages. In addition, two other candidates were found: the \(\alpha\)-farnesene and \(\alpha\)-pinene synthases (_AFS_ and _APS_, respectively). The first gene was found with an early differential expression in T2 redirecting FPP to promote \(\alpha\)-farnesene biosynthesis. The second gene was found differentially expressed in T7, redirecting GPP to promote \(\alpha\)-pinene biosynthesis (Figure 3). Both transcripts were expressed only in SR siblings, probably decreasing the GGPP production in the SR phenotype. Thus, the transcriptomic data suggest lower GGPP production in SR siblings during ripening by the canonical GGPP biosynthesis pathway, ans also FPP and GPP redirection to terpene biosynthesis, further reducing GGPP production in these individuals in the early developmental stages. \begin{table}
\begin{tabular}{l c c c c c c c c c} \hline \hline \multirow{2}{*}{**GeneName**} & \multicolumn{3}{c}{**Slow Ripening *} & \multicolumn{3}{c}{**Normal Ripening *} & \multicolumn{3}{c}{**Description**} \\ \cline{2-10}  & **T1** & **T2** & **T3** & **T7** & **T1** & **T2** & **T3** & **T7** & \\ \hline Prupe.4G186800 & - & - & - & - & 22.8 & 251.6 & 64.3 & 18.9 & _NAC072_ \\ Prupe.2G176900 & - & - & - & - & 0.1 & 0.0 & 0.1 & 2.4 & _ACS1_ \\ Prupe.4G126600 & 26.4 & 183.7 & 72.7 & 15.3 & - & - & - & - & _AFS1_ \\ Prupe.4G126400 & 2.6 & 15.9 & 7.2 & 1.2 & - & - & - & - & _AFS1_ \\ Prupe.8G080700 & - & - & - & - & 15.1 & 5.7 & 1.7 & 39.7 & SAUR family protein \\ Prupe.2G085100 & - & - & - & - & 0.0 & 0.0 & 0.0 & 30.6 & Glucosyl transferase \\ Prupe.8G081800 & - & - & - & - & 0.0 & 0.0 & 0.0 & 1.9 & SAUR family protein \\ Prupe.8G081200 & - & - & - & - & 0.0 & 0.0 & 0.0 & 1.9 & SAUR family protein \\ Prupe.1G043300 & 1.1 & 0.0 & 0.5 & 1.1 & - & - & - & - & Cell number regulator \\ Prupe.4G237600 & 0.4 & 0.2 & 0.5 & 0.1 & - & - & - & - & Cell division control \\ Prupe.8G081300 & - & - & - & - & 0.0 & 0.0 & 0.0 & 1.0 & SAUR family protein \\ Prupe.1G442200 & - & - & - & - & 0.0 & 0.0 & 0.0 & 0.7 & SAUR family protein \\ Prupe.8G079700 & - & - & - & - & 0.1 & 0.0 & 0.0 & 0.4 & _GA20 vx3_ \\ \hline \hline \end{tabular}  
* Normalized expression represented in FPKM values. No gene expression values in one condition are represented by hyphens (-).  
\end{table} 
Table 1: _NAC072_ candidate genes related to gene expression profiles. The expression patterns of the transcripts belonging to the ABA biosynthesis pathway (Figure 3, red section) resulted in a similar expression profiles between NR and SR individuals in T1, T2, and T3. However, in T7, a higher abundance of all transcripts related to the  
Figure 3: Graphical representation of hormone biosynthetic pathways related to fruit development. Schematic diagram of different hormone biosynthetic pathways related to fruit development are represented in separated colored boxes. Each transcript involved in a specific hormone biosynthetic step is in bold, and their expression profiles are represented in different graphs only for genes with differential expression identified by RNAseq with FDR < 0.05 and FC > 111. The expression profiles of the NR and SR transcripts are represented on the left and right side of each graph, respectively.