Tropical Eco-Agriculture Research Institute, Yunnan Academy of Agricultural Sciences, Nancheng Street 150, Yuanmou, 651300, Yunnan, China.
Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, Higashi 1-1-1, Tsukuba, Ibaraki, 305-8566, Japan.
Planta. 2023 Sep 25;258(5):85. doi: 10.1007/s00425-023-04240-x.
For the first time, stone cells in pear and apple pedicel were studied. The lignification of the pedicel outer part was correlated with flesh, and the secondary cell wall biosynthesis genes were activated. Fruit pedicels act as bridges between the fruit and the shoot. They have secondary thickened cell walls that presumably function in mechanical support, water and nutrient transport. Stone cells are cells with a secondary cell wall thickening. In pears, yet not in apples, the stone cells affect the flesh texture. There have been few reports on stone cell formation in pear and apple pedicels; therefore, we studied these cells for the first time. The apple pedicel had few stone cells in the cortex. The formation of stone cells in pear continued until seven weeks after flowering (WAF), and the density was significantly higher than in apple. The stone cell formation degree (SFD) of pear was 3.6-7.1 times higher than that of apple. Total lignin and lignin non-condensed structure (G and S units) content in the pear pedicle outer part was 1.5-2.7 times higher than that of the apple at harvest. The SFD of the pedicel outer part had a positive correlation with the G and S units content of the flesh. The total lignin and G and S units content between flesh and the pedicel outer part were positively correlated. Correlation analysis revealed a positive relationship between fruit and pedicel formation of the stone cells. The WGCNA showed that NST3 was linked to NAC028, MYB46, CESA, POD, LAC, and VSR6. These genes were highly expressed in the outer part of the pear pedicel, while they were suppressed in that issue of the apple at 4 WAF.
首次研究了梨和苹果果柄中的石细胞。果柄外部木质化与果肉相关，次生细胞壁生物合成基因被激活。果实果柄是果实与茎之间的桥梁。它们具有次生加厚的细胞壁，推测其功能是机械支撑、水分和养分运输。石细胞是具有次生细胞壁加厚的细胞。在梨中，而非苹果中，石细胞会影响果肉质地。关于梨和苹果果柄中石细胞的形成已有少量报道；因此，我们首次对这些细胞进行了研究。苹果果柄的皮层中石细胞较少。梨的石细胞形成持续到开花后 7 周（WAF），密度明显高于苹果。梨的石细胞形成程度（SFD）比苹果高 3.6-7.1 倍。收获时，梨果柄外部总木质素和木质素非缩合结构（G 和 S 单位）含量比苹果高 1.5-2.7 倍。果柄外部 SFD 与果肉 G 和 S 单位含量呈正相关。果肉和果柄外部之间的总木质素和 G 和 S 单位含量呈正相关。相关分析显示，果实和果柄石细胞的形成之间存在正相关关系。WGCNA 表明 NST3 与 NAC028、MYB46、CESA、POD、LAC 和 VSR6 相关。这些基因在梨果柄外部高度表达，而在苹果的 4 WAF 时则受到抑制。
