A 224-bp Indel in the Promoter of PeMYB114 Accounts for Anthocyanin Accumulation of Skin in Passion Fruit (Passiflora spp.).

Passion fruit (Passiflora spp.) is an important fruit tree in the family Passifloraceae. The color of the fruit skin, a significant agricultural trait, is determined by the content of anthocyanin in passion fruit. However, the regulatory mechanisms behind the accumulation of anthocyanin in different passion fruit skin colors remain unclear. In the study, we identified and characterized a R2R3-MYB transcription factor, PeMYB114, which functions as a transcriptional activator in anthocyanin biosynthesis. Yeast one-hybrid system and dual-luciferase analysis showed that PeMYB114 could directly activate the expression of anthocyanin structural genes (PeCHS and PeDFR). Furthermore, a natural variation in the promoter region of PeMYB114 alters its expression. PeMYB114purple accessions with the 224-bp insertion have a higher anthocyanin level than PeMYB114yellow accessions with the 224-bp deletion. The findings enhance our understanding of anthocyanin accumulation in fruits and provide genetic resources for genome design for improving passion fruit quality.

The knockdown efficiency of telomere associated genes with specific methodology in a zebrafish cell line.

Zebrafish is broadly used as a model organism in gene loss-of-function studies in vivo, but its employment in vitro is greatly limited by the lack of efficient gene knockdown approaches in zebrafish cell lines such as ZF4. In this article, we attempted to induce silencing of telomere associated genes in ZF4 by applying the frequently-used siRNA transfection technology and a novel moiety-linked morpholino (vivo-MO). By proceeding with integrated optimization of siRNAs transfection and vivo-MOs treatment, we compared five transfection reagents and vivo-MOs simultaneously to evaluate the efficiency of terfa silencing in ZF4. 48 h after siRNAs transfection, Lipofectamine™ 3000 and X-tremeGENE™ HP leaded to knockdown in 35% and 43% of terfa transcription, respectively, while vivo-MO-terfa modulated 58% down-expression of zfTRF2 in contrast to vivo-MO-ctrl 72 h after treatment. Further siRNAs transfection targeting telomere associated genes by X-tremeGENE™ HP showed silencing in 40-68% of these genes without significant cytotoxicity and off-target effect. Our results confirmed the feasibility of gene loss-of-function studies in a zebrafish cell line, offered a systematic optimizing strategy to employ gene silencing experiments, and presented Lipofectamine™ 3000, X-tremeGENE™ HP and vivo-morpholinos as candidate gene silencing approaches for zebrafish in vitro gene loss-of-function studies. Successfully knockdown of shelterin genes further opened a new field for telomeric study in zebrafish.