A Tree Peony Trihelix Transcription Factor PrASIL1 Represses Seed Oil Accumulation

Abstract

In many higher plants, seed oil accumulation is governed by complex multilevel regulatory networks including transcriptional regulation, which primarily affects fatty acid biosynthesis. Tree peony (Paeonia rockii), a perennial deciduous shrub endemic to China is notable for its seed oil that is abundant in unsaturated fatty acids. We discovered that a tree peony trihelix transcription factor, PrASIL1, localized in the nucleus, is expressed predominantly in developing seeds during maturation. Ectopic overexpression of PrASIL1 in Nicotiana benthamiana leaf tissue and Arabidopsis thaliana seeds significantly reduced total fatty acids and altered the fatty acid composition. These changes were in turn associated with the decreased expression of multitudinous genes involved in plastidial fatty acid synthesis and oil accumulation. Thus, we inferred that PrASIL1 is a critical transcription factor that represses oil accumulation by down-regulating numerous key genes during seed oil biosynthesis. In contrary, up-regulation of oil biosynthesis genes and a significant increase in total lipids and several major fatty acids were observed in PrASIL1-silenced tree peony leaves. Together, these results provide insights into the role of trihelix transcription factor PrASIL1 in controlling seed oil accumulation. PrASIL1 can be targeted potentially for oil enhancement in tree peony and other crops through gene manipulation.

Tree peony transcription factor PrWRI1 enhances seed oil accumulation

“…Ectopic expression of WRI1s from castor and oat were also found to enhance TAG levels in N. benthamiana fresh leaves relative to the control [ 29 , 33 ]. In addition to this, the visualizations of LDs in N. benthamiana leaves will be greatly helpful for the investigation of TAG accumulations, which also have been used in our other study on PrASIL1 [ 42 ]. And, our results would provide a promising strategy to increase the production of vegetable leaves oils to meet the increasing demand for edible oil [ 43 ].…”

The tree peony nuclear factor Y transcription factor PrNF‐YC2 promotes seed oil accumulation

“…At 6 dpi, LDs were dyed using Nile Red (YUANYE). Acquisition of confocal images and visualization of LDs are as previously described (Yang et al., 2021).…”

“…The inflorescences of WT Arabidopsis were infiltrated with a GV3101 suspension containing 35S:PrNF‐YC2 (Clough & Bent, 1998). T0 seeds were collected and germinated on 1/2 Murashige and Skoog medium containing hygromycin (25 mg L −1 ) for selection, the positive transgenic lines were confirmed as previously described (Yang et al., 2021). Transgenic plants were grown to the T3 generation to acquire homozygous lines.…”

“…Recently, molecular studies on seed oil accumulation in tree peony have attracted growing interest. We are also investigating the FA biosynthesis pathway in tree peony seeds (Zhang et al., 2018; Zhang et al., 2019), and the transcriptional regulation of PrASIL1 TF (Yang et al., 2021). So far, previous studies have mainly revolved around the identification of oil biosynthetic genes of tree peony; however, the regulatory functions of TFs involved in oil accumulation are less known and thus warrant further investigation.…”

Trihelix Transcriptional Factor GhGT26 of Cotton Enhances Salinity Tolerance in Arabidopsis

“…According to previous reports, this family was confined to the regulation of light-responsive genes [ 17 ]. Recent studies have indicated that the trihelix family also has important functions in different processes of growth and development involving morphogenesis of perianth organs, the formation of trichomes and stomata, seed oil accumulation and the seed abscission layer, kernel development, and late embryogenesis development [ 18 , 19 , 20 , 21 ]. Trihelix proteins are presently proposed to be involved in regulating plant responses to abiotic stresses.…”