Transcriptome Analysis Reveals Candidate Genes Involved in Gibberellin-Induced Fruit Setting in Triploid Loquat (Eriobotrya japonica)

Abstract

The triploid loquat (Eriobotrya japonica) is a new germplasm with a high edible fruit rate. Under natural conditions, the triploid loquat has a low fruit setting ratio (not more than 10 fruits in a tree), reflecting fertilization failure. To unravel the molecular mechanism of gibberellin (GA) treatment to induce parthenocarpy in triploid loquats, a transcriptome analysis of fruit setting induced by GA3 was analyzed using RNA-seq at four different stages during the development of young fruit. Approximately 344 million high quality reads in seven libraries were de novo assembled, yielding 153,900 unique transcripts with more than 79.9% functionally annotated transcripts. A total of 2,220, 2,974, and 1,614 differentially expressed genes (DEGs) were observed at 3, 7, and 14 days after GA treatment, respectively. The weighted gene co-expression network and Venn diagram analysis of DEGs revealed that sixteen candidate genes may play critical roles in the fruit setting after GA treatment. Five genes were related to auxin, in which one auxin synthesis gene of yucca was upregulated, suggesting that auxin may act as a signal for fruit setting. Furthermore, ABA 8′-hydroxylase was upregulated, while ethylene-forming enzyme was downregulated, suggesting that multiple hormones may be involved in GA signaling. Four transcription factors, NAC7, NAC23, bHLH35, and HD16, were potentially negatively regulated in fruit setting, and two cell division-related genes, arr9 and CYCA3, were upregulated. In addition, the expression of the GA receptor gid1 was downregulated by GA treatment, suggesting that the negative feedback mechanism in GA signaling may be regulated by gid1. Altogether, the results of the present study provide information from a comprehensive gene expression analysis and insight into the molecular mechanism underlying fruit setting under GA treatment in E. japonica.

Transcriptomic profiling and discovery of key genes involved in adventitious root formation from green cuttings of highbush blueberry (Vaccinium corymbosum L.)

“…The qRT-PCR were carried out on a LightCycler 480 Real-Time PCR System (Roche, Basal, Switzerland) in a total volume of 10 μl containing 5.0 μl SYBR Premix ExTaq™ (RR820A), 0.5 μl of each primer (10 uM), 2 μl of cDNA and 2 μl ddH 2 O. The PCR conditions were described detail in Jiang et al (2016) [73]. GAPDH was used as internal control.…”

EjFRI, FRIGIDA (FRI) Ortholog from Eriobotrya japonica, Delays Flowering in Arabidopsis

“…The PCR system was followed: 95 • C for 30 s, followed by 40 cycles of 95 • C for 20 s and 56 • C for 1 min, and a melt cycle from 65 to 95 • C. After that, qEjFRI-F/R were used for detecting the spatiotemporal expression of EjFRI. As an internal control, the actin gene, qEjactin-F/R (JN004223), was used to normalized small differences in samples [60]. The gene expression level was analyzed by the 2 −∆∆Ct method described by Livak and Schmittegen [61].…”

Transcriptomic profiling and discovery of key genes involved in adventitious root formation from green cuttings of highbush blueberry (Vaccinium corymbosum L.)

“…The reaction was performed on a LightCycler 480 Real-Time PCR System (Roche, Basal, Switzerland). qRT-PCR was initiated as follows: 95°C for 30s, then repeated 40 cycles at 95 °C for 5s and 60 °C for 20s [74]. Template-less controls for each primer pair were included in each run.…”