Xu Yusheng, Xu Lan, Zhang Mingliang, Wang Hao, Wang Yuqian, Zhang Xueping, Zhang Kaijing, Sui Yihu, Qian Jingjing, Jia Shuangshuang, Qian Ming, Cui Guangrong
Department of Horticulture, College of Agriculture, Anhui Science and Technology University, Chuzhou, 233100, China.
College of Horticulture, Nanjing Agricultural University, Nanjing, 210032, China.
BMC Genomics. 2025 Mar 31;26(1):321. doi: 10.1186/s12864-025-11429-9.
β-galactosidase (BGAL), which is an important cell wall-degrading enzyme, participates in various biological processes, but its effects on pollen tube growth (PTG) remain unclear.
We identified 12 PbrBGAL genes (named PbrBGAL1-12) in the pear (Pyrus bretschneideri) genome. PbrBGAL members, containing three conserved domains and two enzyme active sites, were grouped into six subclasses. They were distributed in seven chromosomes, with dispersed duplication revealed as the main replication event. PbrBGAL genes contained 1 to 24 exons and 0 to 23 introns, with exon/intron structure mostly conserved within each subclass except for subclass E. Analyses of tissue-specific expression indicated that only PbrBGAL6 was highly expressed specifically in anther and pollen, with decreasing expression levels during PTG. The effective inhibition of PbrBGAL6 expression using antisense oligodeoxynucleotide technology dramatically decreased BGAL enzymatic activity, promoted PTG and increased cytoplasmic leakage and tip widths. Furthermore, suppressing PbrBGAL6 transcription decreased the apical total and methylated pectin contents in pollen tubes by significantly increasing transcription of PbrPME11, PbrPG14, PbrPG20, PbrPG21 and PbrPG24.
We identified 12 PbrBGAL genes in the pear genome, of which PbrBGAL6 precisely modulates the apical pectin content to mediate pear PTG through its effects on PbrPME11 and PbrPGs expression. This study provides direct evidence of the involvement of BGAL in the regulation of polar PTG.
β-半乳糖苷酶（BGAL）是一种重要的细胞壁降解酶，参与多种生物学过程，但其对花粉管生长（PTG）的影响尚不清楚。
我们在梨（Pyrus bretschneideri）基因组中鉴定出12个PbrBGAL基因（命名为PbrBGAL1 - 12）。PbrBGAL成员包含三个保守结构域和两个酶活性位点，被分为六个亚类。它们分布在七条染色体上，主要的复制事件为分散重复。PbrBGAL基因包含1至24个外显子和0至23个内含子，除E亚类外，每个亚类内的外显子/内含子结构大多保守。组织特异性表达分析表明，只有PbrBGAL6在花药和花粉中特异性高表达，在花粉管生长过程中表达水平降低。使用反义寡脱氧核苷酸技术有效抑制PbrBGAL6的表达显著降低了BGAL酶活性，促进了花粉管生长，并增加了细胞质泄漏和顶端宽度。此外，抑制PbrBGAL6转录通过显著增加PbrPME11、PbrPG14、PbrPG20、PbrPG21和PbrPG24的转录，降低了花粉管顶端的总果胶和甲基化果胶含量。
我们在梨基因组中鉴定出12个PbrBGAL基因，其中PbrBGAL6通过影响PbrPME11和PbrPGs的表达，精确调节顶端果胶含量以介导梨的花粉管生长。本研究为BGAL参与极性花粉管生长调控提供了直接证据。
