Chen Jinyuan, Qu Chunpu, Chang Ruhui, Suo Juanfang, Yu Jiajie, Sun Xue, Liu Guanjun, Xu Zhiru
1Key Laboratory of Saline-Alkali Vegetation Ecology Restoration (Northeast Forestry University), Ministry of Education, Harbin, 150040 People's Republic of China.
2College of Life Science, Northeast Forestry University, Harbin, 150040 People's Republic of China.
3 Biotech. 2020 Feb;10(2):57. doi: 10.1007/s13205-020-2061-5. Epub 2020 Jan 22.
β-d-xylosidase (BXL) hydrolyzes xylobiose and xylo-oligosaccharides into xylose monomers, and is a rate-limiting enzyme in the degradation of hemicellulose in the cell wall. In this study, ten genes encoding putative BXL proteins were identified in the genome by bioinformatics methods. In the phylogenetic analysis, the PtBXLs formed two subfamilies. and were closely related to , an important enzyme in the normal development of the cell wall structure. Chromosomal distribution and genome synteny analyses revealed two tandem-duplicated gene pairs and on chromosomes II and V, respectively, and six segmental-duplicated gene pairs on chromosomes II, V, VIII, X, and XIV among the gene family. Tissue-specific expression data from PlantGenIE indicated that , , and were highly expressed in stems. Quantitative real-time RT-PCR analyses revealed that , , and were up-regulated in the upper stem in response to the low and high ammonium and nitrate treatments. The influence of nitrogen on the expression of , , and genes may affect the formation of the plant secondary cell wall. This comprehensive analysis of the family in poplar provides new insights into their regulation by nitrogen and increases our understanding of the roles of BXLs in hemicellulose metabolism in the secondary cell wall and during plant development.
β-D-木糖苷酶（BXL）将木二糖和木寡糖水解为木糖单体，是细胞壁中半纤维素降解的限速酶。在本研究中，通过生物信息学方法在基因组中鉴定出10个编码假定BXL蛋白的基因。在系统发育分析中，PtBXLs形成了两个亚家族。并且与细胞壁结构正常发育中的一种重要酶密切相关。染色体分布和基因组共线性分析分别揭示了基因家族中位于染色体II和V上的两个串联重复基因对和，以及位于染色体II、V、VIII、X和XIV上的六个片段重复基因对。来自PlantGenIE的组织特异性表达数据表明，、、和在茎中高度表达。实时定量RT-PCR分析表明，、和在茎上部对低铵和高铵及硝酸盐处理有上调表达。氮对、和基因表达的影响可能会影响植物次生细胞壁的形成。对杨树中家族的这种综合分析为氮对其调控提供了新见解，并增进了我们对BXLs在次生细胞壁半纤维素代谢及植物发育过程中作用的理解。
