{"database":"biostudies-literature","file_versions":[],"scores":null,"additional":{"submitter":["Liu X"],"funding":["the Science and Technology Development Project of Jilin Province"],"pagination":["3606"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/S-EPMC12694366"],"repository":["biostudies-literature"],"omics_type":["Unknown"],"volume":["14(23)"],"pubmed_abstract":["Phenylalanine ammonia-lyase (PAL) catalyzes the first committed step in the phenylpropanoid pathway that governs the entry of carbon flux into flavonoid biosynthesis and stress-responsive metabolism. However, how PAL explicitly mediates hormonal-induced flavonoid biosynthesis and promotes the antioxidant defense system in safflower (<i>Carthamus tinctorius</i> L.) remains largely unknown. Here, we functionally characterize CtPAL1 and demonstrated its regulatory role in abscisic acid (ABA)-induced flavonoid biosynthesis and antioxidant defense. Using phylogenetic and structural predictions, we found that CtPAL1 was placed within a conserved branch of Asteraceae PAL proteins. A promoter analysis indicated multiple hormone- and stress-responsive cis-elements, and exposure to abiotic and hormonal treatments elicited complex, stimulus-dependent dynamics of <i>CtPAL1</i> expression and flavonoid accumulation. Upon ABA treatment, the expression of <i>CtPAL1</i> is rapidly induced, triggering early flavonoid biosynthesis. Moreover, <i>CtPAL1</i>-overexpressing Arabidopsis lines exhibited enhanced tolerance to ABA-induced stress by lower lipid peroxidation and higher antioxidant enzyme activities, accompanied with increased flavonoid production. Importantly, the transgenic overexpression of <i>CtPAL1</i> in Arabidopsis led to the upregulation of the upstream flavonoid pathway genes (At4CL, AtCHI) and elevated total flavonoid levels (1.07-1.27-fold versus wild type), while silencing in safflower caused a reduced flavonoid content (0.52-0.77× controls) and the downregulation of pathway genes. A biochemical assay also confirms that recombinant CtPAL1 efficiently converts L-phenylalanine to trans-cinnamic acid, validating its catalytic function. Together, our results demonstrate that CtPAL1 functions as a highly conserved and functionally active PAL enzyme in safflower and acts as an ABA-responsive modulator of flavonoid biosynthesis and antioxidant defense."],"journal":["Plants (Basel, Switzerland)"],"pubmed_title":["The Phenylpropanoid Gatekeeper CtPAL1 Coordinates ABA-Induced Flavonoid Biosynthesis and Oxidative Stress Tolerance in Safflower (&lt;i&gt;Carthamus tinctorius&lt;/i&gt; L.)."],"pmcid":["PMC12694366"],"funding_grant_id":["20220204058YY"],"pubmed_authors":["Liu X","Zhang G","Dai M","Hu Y","Zhang J","Yao N","Ahmad N","Zhao H","Ma W"],"additional_accession":[]},"is_claimable":false,"name":"The Phenylpropanoid Gatekeeper CtPAL1 Coordinates ABA-Induced Flavonoid Biosynthesis and Oxidative Stress Tolerance in Safflower (&lt;i&gt;Carthamus tinctorius&lt;/i&gt; L.).","description":"Phenylalanine ammonia-lyase (PAL) catalyzes the first committed step in the phenylpropanoid pathway that governs the entry of carbon flux into flavonoid biosynthesis and stress-responsive metabolism. However, how PAL explicitly mediates hormonal-induced flavonoid biosynthesis and promotes the antioxidant defense system in safflower (<i>Carthamus tinctorius</i> L.) remains largely unknown. Here, we functionally characterize CtPAL1 and demonstrated its regulatory role in abscisic acid (ABA)-induced flavonoid biosynthesis and antioxidant defense. Using phylogenetic and structural predictions, we found that CtPAL1 was placed within a conserved branch of Asteraceae PAL proteins. A promoter analysis indicated multiple hormone- and stress-responsive cis-elements, and exposure to abiotic and hormonal treatments elicited complex, stimulus-dependent dynamics of <i>CtPAL1</i> expression and flavonoid accumulation. Upon ABA treatment, the expression of <i>CtPAL1</i> is rapidly induced, triggering early flavonoid biosynthesis. Moreover, <i>CtPAL1</i>-overexpressing Arabidopsis lines exhibited enhanced tolerance to ABA-induced stress by lower lipid peroxidation and higher antioxidant enzyme activities, accompanied with increased flavonoid production. Importantly, the transgenic overexpression of <i>CtPAL1</i> in Arabidopsis led to the upregulation of the upstream flavonoid pathway genes (At4CL, AtCHI) and elevated total flavonoid levels (1.07-1.27-fold versus wild type), while silencing in safflower caused a reduced flavonoid content (0.52-0.77× controls) and the downregulation of pathway genes. A biochemical assay also confirms that recombinant CtPAL1 efficiently converts L-phenylalanine to trans-cinnamic acid, validating its catalytic function. Together, our results demonstrate that CtPAL1 functions as a highly conserved and functionally active PAL enzyme in safflower and acts as an ABA-responsive modulator of flavonoid biosynthesis and antioxidant defense.","dates":{"release":"2025-01-01T00:00:00Z","publication":"2025 Nov","modification":"2026-05-26T11:01:31.199Z","creation":"2026-05-24T03:12:04.243Z"},"accession":"S-EPMC12694366","cross_references":{"pubmed":["41375316"],"doi":["10.3390/plants14233606"]}}