Gong Xin, Qi Kaijie, Zhao Liangyi, Xie Zhihua, Pan Jiahui, Yan Xin, Shiratake Katsuhiro, Zhang Shaoling, Tao Shutian
Sanya Institute, State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, China.
College of Horticulture, Xinjiang Agricultural University, Urumqi, China.
Plant J. 2024 Dec;120(5):1933-1953. doi: 10.1111/tpj.17090. Epub 2024 Oct 24.
Lignification of the cell wall in pear (Pyrus) fruit results in the formation of stone cells, which affects the texture and quality of the fruit. However, it is still unclear that how different transcription factors (TFs) work together to coordinate the synthesis and deposition of lignin. Here, we examined the transcriptome of pear varieties with different stone cell contents and found a key TF (PbAGL7) that can promote the increase of stone cell contents and secondary cell wall thicknesses. In addition, PbAGL7 can facilitate the expression level of lignin biosynthesis-related genes and accelerate the lignin biosynthesis in pear fruit and Arabidopsis. However, PbAGL7 did not directly bind to the promoters of PbC3H1 and PbHCT17 which are crucial genes involved in lignin biosynthesis. On the other hand, yeast two-hybrid (Y2H) library showed that PbNAC47 and PbMYB73 interacted with PbAGL7 in the nucleus. PbNAC47 and PbMYB73 also increased the stone cell and lignin contents, and upregulated the expressions of PbC3H1 and PbHCT17 by binding to the SNBE and AC elements, respectively. Moreover, PbNAC47 also interacted with PbMYB73 to form PbAGL7-PbNAC47-PbMYB73 complex. This complex significantly activated the expression levels of PbC3H1 and PbHCT17 and promoted lignin biosynthesis to form stone cells in pear fruit. Overall, our study provides new insights into the molecular mechanism of TFs that coordinately regulate the stone cell formation in pear fruit and extend our knowledge to understand cell wall lignification in plants.
梨（Pyrus）果实细胞壁的木质化会导致石细胞的形成，这会影响果实的质地和品质。然而，目前尚不清楚不同的转录因子（TFs）如何协同作用来协调木质素的合成与沉积。在此，我们研究了具有不同石细胞含量的梨品种的转录组，并发现了一个关键的转录因子（PbAGL7），它可以促进石细胞含量的增加和次生细胞壁厚度的增加。此外，PbAGL7可以促进梨果实和拟南芥中木质素生物合成相关基因的表达水平，并加速木质素的生物合成。然而，PbAGL7并未直接结合到参与木质素生物合成的关键基因PbC3H1和PbHCT17的启动子上。另一方面，酵母双杂交（Y2H）文库显示PbNAC47和PbMYB73在细胞核中与PbAGL7相互作用。PbNAC47和PbMYB73也增加了石细胞和木质素的含量，并分别通过结合SNBE和AC元件上调了PbC3H1和PbHCT17的表达。此外，PbNAC47还与PbMYB73相互作用形成PbAGL7-PbNAC47-PbMYB73复合物。该复合物显著激活了PbC3H1和PbHCT17的表达水平，并促进木质素生物合成以在梨果实中形成石细胞。总体而言，我们的研究为转录因子协同调节梨果实石细胞形成的分子机制提供了新的见解，并扩展了我们对植物细胞壁木质化的认识。
