Identification and Functional Characterization of Genes Involved in the Biosynthesis of Caffeoylquinic Acids in Sunflower (Helianthus annuus L.)

Abstract

Sunflower ( Helianthus annuus L.) sprouts accumulate high amounts of caffeoylquinic acids (CQAs) including chlorogenic acid (5-CQA) and 1,5-diCQA. These compounds, which can be found in many plants, including tomato, globe artichoke, and chicory, have many health benefits, including antioxidant, antihepatotoxic, and antiglycative activities. However, CQA profiles and biosynthesis have not previously been studied in sunflower sprouts. In the present study, we found that 5-CQA and 1,5-diCQA were the major CQAs found in sunflower sprouts. We also identified minor accumulation of other CQAs, namely 3-CQA, 4-CQA, 3,4-diCQA, and 4,5-diCQA. According to genome-wide identification and phylogenetic analysis of genes involved in CQA biosynthesis in sunflower, three genes ( HaHQT1 , HaHQT2 , and HaHQT3 ) encoding hydroxycinnamoyl CoA:quinate hydroxycinnamoyl transferase (HQT) and two genes ( HaHCT1 and HaHCT2 ) encoding hydroxycinnamoyl CoA:shikimate/quinate hydroxycinnamoyl transferase (HCT) were identified. Expression analysis of these five genes in hypocotyls and cotyledons strongly suggested that HaHQT2 could be the main enzyme responsible for CQA biosynthesis, as HaHQT2 had the highest expression levels. In addition, when transiently expressed in the leaves of Nicotiana benthamiana , all three HaHQTs, which were soluble and not membrane-bound enzymes, could increase the content of 5-CQA by up to 94% compared to that in a control. Overall, our results increase understanding of CQA biosynthesis in sunflower sprouts and could be exploited by plant breeders to enhance accumulation of health-promoting CQAs in these plants.

Versatility in acyltransferase activity completes chicoric acid biosynthesis in purple coneflower

“…No putative signal peptides were found in the EpHTT or EpHQT sequences. Both EpHTT and EpHQT GFP-tagged proteins were cytosolically localized as reported for other HQTs 19 , 20 and showed highest activities at pH 7 (Fig. 2h and Supplementary Fig.…”

Integrated transcriptome, small RNA and degradome sequencing approaches proffer insights into chlorogenic acid biosynthesis in leafy sweet potato

“…We investigated two well-characterized genotypes at two stages for their different CGA accumulation ( Fig 2A–2C ). Although a few genes involved in CGA biosynthesis had been reported in other plant species, such as tomato [ 21 , 22 ], Arabidopsis [ 23 , 24 ], Nicotiana tabacum [ 27 ], Lonicera japonica [ 50 , 51 ], Sunflower [ 52 ], Dandelions [ 53 , 54 ], Cecropia obtusifolia [ 55 ], the molecular mechanisms underlying in leafy sweet potato remains largely unknown. In the present study, a total of 29834 genes were identified based on the reference guided transcriptome analysis of two genotypes at two stages.…”

Rhizophagus irregularis and Rhizoctonia solani Differentially Elicit Systemic Transcriptional Expression of Polyphenol Biosynthetic Pathways Genes in Sunflower

“…The specific primer sequences of sunflower genes, PAL1, C4H, CHS, CHI2, F3H, FLS1, DFR, F3 H, AN1, AN2, HCT, HQT, and C3H, were designed and are mentioned in Table 1, and the β-actin gene was used as an internal standard due to their stable expression in sunflower based on previous studies [19]. The qRT-PCR reaction was performed while using a CFX Connect TM Real Time System (BIO-RAD, Hercules, CA, USA).…”

“…In sunflower, the phenolic compounds represent the most prominent bioactive compounds [19]. The polyphenol biosynthetic pathway can be divided into three sections: the main phenylpropanoid, flavonoid, and the chlorogenic acid biosynthetic pathway.…”