Potato is the third largest food crop in the world.Chlorogenic acid is the most important phenolic compound in potato,and also one of the material basis of potato insect resistance and disease resistance.However,excessive chlorogenic acid can af-fect the taste of tuber,therefore,breeding varieties with high chlorogenic acid content in the ground part and low chlorogenic acid content in tuber flesh can well meet the needs of potato disease resistance and quality taste.In order to clarify the molecular regu-lation mechanism of chlorogenic acid in potato,we used the promoter sequence of StHQT,a key enzyme for chlorogenic acid synthesis,as bait to screen the yeast single hybridization library,and identified the transcription factor StAHL of an AT-hook gene family.Further,the bioinformatic characteristics,the relative expression patterns,and subcellular localization of protein products of StAHL were systematically analyzed,and the transcriptional activity between StAHL and StHQT promoters was verified by yeast single hybridization and double luciferase report experiments.The results showed that StAHL gene expression was not tissue specific,but relatively high in roots and flowers.StAHL protein products contained two conserved domains,AT-Hook and DUF296,and were localized in the nucleus.StAHL proteins acted directly on StHQT promoter sequences and inhibited transcrip-tional activity.This suggests that StAHL may inhibit the accumulation of chlorogenic acid in potato by inhibiting StHQT expres-sion.The results laid a foundation for revealing the molecular mechanism of chlorogenic acid biosynthesis in potato,and provided a molecular target for the breeding practices in potato.
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