Candidate gene mining of GA-mediated regulation of pear fruit shape

Abstract

Fruit shape is one of the important traits for quality evaluation, classification, and market grading of horticultural crops. In order to explore the genes regulating pear fruit shape formation, pear varieties ‘Huangguan’ and ‘Korla Fragrant Pear’ with significant differences in fruit shape were selected as experimental materials. Through morphological observation, measurement of fruit longitudinal diameter and fruit transverse diameter, and fruit shape index analysis of the pear fruit growth and development period, the formation of pear fruit shape during the young fruit period was preliminarily determined. By analyzing the transcriptome data of ‘Huangguan’ and ‘Korla Fragrant Pear’ at the young fruit stage, 8993 differentially expressed genes were obtained, and the majority of the genes were annotated to the plant hormone signaling pathway, among which gibberellin-related genes accounted for 13.4%. Spraying GA₃ at the full-bloom stage can significantly prolong the shape of oriental pear. The results of qRT-PCR showed that the expression level of the gibberellin metabolic pathway gene PbGA2ox11 in ‘Huangguan’ was significantly higher than that in ‘Korla Fragrant Pear’. GA₃ treatment inhibited the expression of this gene in ‘Korla Fragrant Pear’, while PP₃₃₃ promoted the expression. It was speculated that PbGA2ox11 was most likely to regulate the shape of pear fruit by regulating gibberellin metabolism. This study provides a new method for studying fruit shape via the analysis of the gibberellin synthesis metabolic pathway, new resources for the rational use of plant growth regulators, and theoretical and technical support for cultivating excellent fruit shape.