Biotechnology Research Institute, Universiti Malaysia Sabah, Jln UMS, 88400, Kota Kinabalu, Sabah, Malaysia.
School of Biological Sciences, Universiti Sains Malaysia, 11800, Penang, Malaysia.
Mol Biol Rep. 2021 Apr;48(4):3285-3301. doi: 10.1007/s11033-021-06321-0. Epub 2021 Apr 20.
Trichoderma is a genus of soil-borne fungus with an abundance of reports of its economic importance in the agriculture industry. Thus, the correct identification of Trichoderma species is necessary for its commercial purposes. Globally, Trichoderma species are routinely identified from micro-morphological descriptions which can be tedious and prone to errors. Thus, we emphasize that the accurate identification of Trichoderma strains requires a three-pronged approach i.e. based on its morphological characteristics, multilocus gene sequences of the rDNA [internal transcribed spacer (ITS) 1 and 2 regions], translation elongation factor 1-α (TEF-1α), Calmodulin (CAL) and its lignocellulolytic activities. We used this approach to identify a total of 53 Trichoderma strains which were isolated from a wet paddy field located at Tuaran, Sabah, Malaysia. The 53 strains were positively identified as belonging to three Trichoderma species, namely T. asperellum (43 strains), T. harzianum (9 strains), and T. reesei (one strain) on the basis of its morphological characteristics and multilocus gene sequences. Phylogenetic trees constructed based on the UPGMA method of the ITS 1 and 2 regions of the rDNA, TEF-1α and CAL revealed three distinct groups with the T. asperellum, T. harzianum and T. reesei strains placed under the section of Trichoderma, Pachybasium and Longibrachiatum, respectively. In addition, the lignocellulolytic activities of the isolates were measured based on the diameters of the halo zones produced when degrading cellulose, lignin, and starch, respectively. This diagnostic assay can be used to identify Trichoderma as it produces polyphenol oxidase when Tannic Acid Media is used for the lignin test, endoglucanases when Jensen media is used for cellulose, and it hydrolyzes starch to glucose when the modified Melin-Nokrans media is used for the starch test. Accurate identification of Trichoderma species is needed as these strains can potentially be used as a biocontrol agent to prevent diseases and to increase yield in agriculture crops.
木霉是一种土壤真菌属，其在农业领域的经济重要性有大量报道。因此，正确鉴定木霉物种对于其商业用途是必要的。在全球范围内，木霉物种通常根据其微观形态描述来进行常规鉴定，这可能既繁琐又容易出错。因此，我们强调，准确鉴定木霉菌株需要采用三管齐下的方法，即基于其形态特征、rDNA [内部转录间隔区（ITS）1 和 2 区域]、翻译延伸因子 1-α（TEF-1α）、钙调蛋白（CAL）和其木质纤维素活性的多基因序列。我们使用这种方法鉴定了总共 53 株从马来西亚 Tuaran 的湿地稻田中分离出来的木霉菌株。根据其形态特征和多基因序列，这 53 株菌株被确认为属于三个木霉物种，即asperellum（43 株）、harzianum（9 株）和 reesei（一株）。基于 rDNA 的 ITS 1 和 2 区域、TEF-1α 和 CAL 的 UPGMA 方法构建的系统发育树显示，三个不同的组，其中 asperellum、harzianum 和 reesei 菌株分别归入 Trichoderma、Pachybasium 和 Longibrachiatum 组。此外，根据降解纤维素、木质素和淀粉时产生的晕圈直径，测量了分离物的木质纤维素活性。这种诊断测定可用于鉴定木霉，因为当使用单宁酸培养基进行木质素试验时，它会产生多酚氧化酶，当使用 Jensen 培养基进行纤维素试验时，它会产生内葡聚糖酶，当使用改良的 Melin-Nokrans 培养基进行淀粉试验时，它会水解淀粉为葡萄糖。需要准确鉴定木霉物种，因为这些菌株可潜在用作生物防治剂，以防止农业作物的疾病并提高产量。
