PbCSE1 promotes lignification during stone cell development in pear ( Pyrus bretschneideri ) fruit

Pear [ Pyrus bretschneideri cv. Dangshan Su] fruit quality is not always satisfactory owing to the presence of stone cells, and lignin is the main component of stone cells in pear fruits. Caffeoyl shikimate esterase (CSE) is a key enzyme in the lignin biosynthesis. Although CSE -like genes have been isolated from a variety of plant species, their orthologs are not characterized in pear. In this study, the CSE gene family ( PbCSE ) from P. bretschneideri was identified. According to the physiological data and quantitative RT-PCR (qRT-PCR), PbCSE1 was associated with lignin deposition and stone cell formation. The overexpression of PbCSE1 increased the lignin content in pear fruits. Relative to wild-type (WT) Arabidopsis , the overexpression of PbCSE1 delayed growth, increased the lignin deposition and lignin content in stems. Simultaneously, the expression of lignin biosynthetic genes were also increased in pear fruits and Arabidopsis . These results demonstrated that PbCSE1 plays an important role in cell lignification and will provide a potential molecular strategy to improve the quality of pear fruits.