Guangxi Botanical Garden of Medicinal Plants, Nanning, 530023, China.
Sci Rep. 2022 May 11;12(1):7744. doi: 10.1038/s41598-022-11940-z.
Taxillus chinensis (DC.) Danser is an extensively used medicinal shrub in the traditional as well as modern systems of medicines. It is a perennial hemiparasitic plant, which is difficult to propagate artificially because of its low parasitic rate. Successful parasitism of parasitic plants is to fuse their tissues and connect their vasculature to the host vasculature building a physiological bridge, which can efficiently withdraw water, sugars and nutrients from their host plants. It is reported that endophytic fungi play an important role in cell wall degradation and fusion, which is the key forming process of the physiological bridge. Therefore, in this study, the endophytic fungi from T. chinensis of different hosts were isolated, and then the organisms that could degrade the main components of the cell walls were screened out using a medium consisting of guaihuol and cellulose degradation capacity. The results showed that five strains were screened out from 72 endophytic fungi of T. chinensis which with high enzyme activities for lignocellulosic degradation. The laccase and cellulase activities of five strains reached their peaks at day 7, and the highest enzyme activities of these two enzymes were found in strain P6, which was 117.66 and 1.66 U/mL, respectively. Manganese peroxidase of strain 4 and lignin peroxidase of strain N6 also reached their peaks at day 7 and were the highest among the 5 strains, with enzyme activities of 11.61 and 6.64 U/mL, respectively. Strains 4, 15, 31, N6 and P6 were identified as Colletotrichum sp., Nigerrospora sphaerica, Exserohilum sp., Diaporthe phaseolorum and Pestalotiopsis sp., respectively, according to their morphological and molecular biology properties. The endophytic fungi may secrete efficient cell wall degradation enzymes, which promote the dissolution and relaxation of the cell wall between T. chinensis and host, thus contributing to the parasitism of T. chinensis.
中国菝葜（DC.）Danser 是传统和现代医学中广泛使用的药用灌木。它是一种多年生半寄生植物，由于寄生率低，人工繁殖困难。寄生植物的成功寄生是融合它们的组织并将它们的脉管系统连接到宿主脉管系统，建立一个生理桥，从而有效地从宿主植物中提取水分、糖和养分。据报道，内生真菌在细胞壁降解和融合中发挥重要作用，这是生理桥形成的关键过程。因此，在这项研究中，从不同宿主的中国菝葜中分离出内生真菌，然后使用含有愈创木酚和纤维素降解能力的培养基筛选出能够降解细胞壁主要成分的生物。结果表明，从 72 株中国菝葜内生真菌中筛选出 5 株具有较高木质纤维素降解酶活性的菌株。5 株菌的漆酶和纤维素酶活性在第 7 天达到峰值，其中菌株 P6 的两种酶的最高酶活分别为 117.66 和 1.66 U/mL。菌株 4 的锰过氧化物酶和菌株 N6 的木质素过氧化物酶也在第 7 天达到峰值，在 5 株菌中酶活最高，分别为 11.61 和 6.64 U/mL。根据形态学和分子生物学特性，菌株 4、15、31、N6 和 P6 分别被鉴定为炭疽菌、黑曲霉、嗜热丝孢菌、菜豆壳球孢菌和拟盘多毛孢。内生真菌可能分泌高效的细胞壁降解酶，促进中国菝葜与宿主之间细胞壁的溶解和松弛，从而促进中国菝葜的寄生。
