PbPDCB16-mediated callose deposition affects the plasmodesmata blockage and reduces lignification in pear fruit

Wen Li; Kaili Yuan; Mei Ren; Zhihua Xie; Kaijie Qi; Xin Gong; Qi Wang; Shaoling Zhang; Shutian Tao

doi:10.1016/j.plantsci.2023.111876

PbPDCB16-mediated callose deposition affects the plasmodesmata blockage and reduces lignification in pear fruit

Plant Sci. 2023 Sep 23:337:111876. doi: 10.1016/j.plantsci.2023.111876. Online ahead of print.

Authors

Wen Li¹, Kaili Yuan¹, Mei Ren¹, Zhihua Xie¹, Kaijie Qi¹, Xin Gong¹, Qi Wang¹, Shaoling Zhang², Shutian Tao³

Affiliations

¹ College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
² College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China; Sanya Institute of Nanjing Agricultural University, Sanya 572000, China.
³ College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China; Sanya Institute of Nanjing Agricultural University, Sanya 572000, China. Electronic address: taost@njau.edu.cn.

PMID: 37748584
DOI: 10.1016/j.plantsci.2023.111876

Abstract

Stone cell, a type of lignified cell, is a unique trait in pear and one of the key factors affects pear fruit quality and economic value. The transmissibility of cell lignification process has been proven to exist, however the effects of callose on the permeability of plasmodesmata (PD) and how to influence cell lignification processes are still unknown. In this study, the genome-wide analysis of PD callose binding proteins (PDCB) gene family in pear genome was performed, and 25 PbPDCB genes were identified and divided into four branches. Similar intron/exon structural patterns were observed in the same branch, strongly supporting their close evolutionary relationship. The expression of PbPDCB16 was negatively correlated with lignin accumulation through qRT-PCR analysis. With transient expression in pear fruit and stable expression in pear calli, the increased callose content accompanied by decreased lignin content was further observed. Besides, compared with wild type Arabidopsis, the transgenic plants grew slowly, and cell walls in the stem were thinner, while fewer PDs were observed on the cell walls, and the interspore filaments were also blocked in transgenic Arabidopsis through the transmission electron microscope (TEM). In summary, overexpression of PbPDCB16 could promote accumulation of callose at PD to affect the PD-mediated intercellular connectivity, and inhibit the intercellular communication. This study will provide new insight in reducing the lignin content through callose deposition, and also provide the theoretical basis for further exploration of lignin metabolism and cell wall lignification to form stone cells in pear fruit.

Keywords: Callose; Lignin; Pear; Plasmodesmata.