Wang Han, Zhang Yingjie, Feng Xiaofeng, Peng Fulei, Mazoor Muhammad Aamir, Zhang Yang, Zhao Yu, Han WenLong, Lu Jinjin, Cao Yunpeng, Cai Yongping
School of Life Sciences, Anhui Agricultural University, Hefei, China.
CAS Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China.
Front Plant Sci. 2022 May 10;13:852001. doi: 10.3389/fpls.2022.852001. eCollection 2022.
BGLU β-glucosidases in glycoside hydrolase family 1 (GH1) are involved in many processes of plant secondary metabolism. In particular, its de-glycosylation function plays an important role in the transport of lignin monolignols. No comprehensive study of the BGLU family in Chinese pear ( Rehd.) has been reported yet. In this study, the 50 BGLU family members from Chinese white pear were identified. Three candidate genes, , , and , that may be involved in lignin synthesis were screened by bioinformatics analysis and qRT-PCR. Subcellular localization showed that all three of these candidate genes were expressed in the extracellular region. Then, we analyzed the functions of and hybridization analysis showed that transcripts were not only localized to some pulp cell walls, lignin deposition, and stone cell areas of a pear fruit, but that was also a small amount of enrichment in normal pear flesh cells. transcripts were only enriched in lignin deposition and stone cell areas of pear fruit. Enzyme activity analysis revealed that GST-PbBGLU1 and GST-PbBGLU16 had a stronger activity and higher catalytic efficiency for coniferin than syringin. In addition, GST-PbBGLU16 exhibited the higher activity and catalytic efficiency for the two substrates compared with GST-PbBGLU1. The transformation of and into identified that the lignin contents of mutant, , and were not changed than that of wild-type. However, compared with wild-type , the overexpression of the plant's lignin increased in varying degrees. The effect of on the lignin increment was greater than that of in . In pear fruits, with transient overexpression of , the contents of lignin and stone cells were significantly higher (0.01 < < 0.05) than those with empty vector injection pear fruits. After transient expression of , lignin in pear fruit increased significantly (0.01 < < 0.05) and stone cells showed a very significant difference ( < 0.01) compared with the control group. However, RNA interference silenced these two genes in pear fruit, which seemed to have no impression on lignin and stone cells. This study provides a molecular biological basis for improving pear fruit quality at the molecular level.
糖苷水解酶家族1（GH1）中的β-葡萄糖苷酶（BGLU）参与植物次生代谢的许多过程。特别是，其去糖基化功能在木质素单体醇的转运中起重要作用。目前尚未见关于中国梨（白梨）中BGLU家族的全面研究报道。在本研究中，鉴定了来自中国白梨的50个BGLU家族成员。通过生物信息学分析和qRT-PCR筛选出3个可能参与木质素合成的候选基因，即 、 和 。亚细胞定位表明，这3个候选基因均在细胞外区域表达。然后，我们分析了 和 的功能，杂交分析表明， 转录本不仅定位于梨果实的一些果肉细胞壁、木质素沉积和石细胞区域，而且在正常梨果肉细胞中也有少量富集。 转录本仅在梨果实的木质素沉积和石细胞区域富集。酶活性分析表明，GST-PbBGLU1和GST-PbBGLU16对松柏苷的活性和催化效率比对丁香苷更强。此外，与GST-PbBGLU1相比，GST-PbBGLU16对这两种底物表现出更高的活性和催化效率。将 和 转化为 发现， 突变体、 和 的木质素含量与野生型相比没有变化。然而，与野生型 相比，该植物的木质素过表达有不同程度的增加。 在 中对木质素增加的影响大于 。在梨果实中，随着 的瞬时过表达，木质素和石细胞的含量显著高于（0.01＜ ＜0.05）空载体注射的梨果实。 在梨果实中瞬时表达后，与对照组相比，木质素显著增加（0.01＜ ＜0.05），石细胞有极显著差异（ ＜0.01）。然而，RNA干扰使梨果实中的这两个基因沉默后，似乎对木质素和石细胞没有影响。本研究为在分子水平上改善梨果实品质提供了分子生物学基础。
