Catechin promotes the germination of Pistacia chinensis seeds via GA biosynthesis

Background and AimsChinese pistachio (Pistacia chinensis Bunge), an important horticultural plant species, holds great ornamental value with beautiful leaves and fruits. Seedling propagation of this tree species is restricted by its erratic seed germination, however, the germination mechanism is ambiguous yet. The aim of this study was to figure out the germination mechanism from the novel perspective based on the multi-omics data.MethodsThe multi-omics technique combined with hormone content measurement was first applied in seed germination of Chinese pistachio.Key ResultsDue to the great accumulation during seed germination, catechin stood out from the identified metabolites by broadly targeted metabolomic analysis. Exogenous catechin of 10 mg/L significantly improved the germination of Chinese pistachio seeds. An interesting result of hormone analysis showed that the improving effect of catechin could be attributed to increase of the gibberellic acid 3 (GA3) content rather than decrease of the abscisic acid (ABA) content before germination. The paclobutrazol (PAC, a GA biosynthesis inhibitor) and PAC + catechin treatments also showed that the promoting effect of catechin on seed germination depends on GA biosynthesis. Transcriptome analysis and qRT‒PCR further revealed that catechin induced the expression of PcGA20ox5 to activate GA biosynthesis. Several transcription factors were induced by catechin and GA treatments, such as TCP, bZIP and C3H, which may play an important regulatory role in GA biosynthesis in a catechin-mediated way.ConclusionsCatechin promotes seed germination via GA biosynthesis in Chinese pistachios. This study proposes a novel mechanism by which catechin promotes seed germination via the GA pathway, which provides new insight into a comprehensive understanding of seed dormancy and germination.