Department of Microbial Biotechnology, National Research Centre, Cairo, Egypt.
Department of Industrial Biotechnology, GEBRI, University of Sadat City, Sadat City, Menofia, Egypt.
BMC Biotechnol. 2024 Jul 6;24(1):46. doi: 10.1186/s12896-024-00872-3.
Microbial growth during plant tissue culture is a common problem that causes significant losses in the plant micro-propagation system. Most of these endophytic microbes have the ability to propagate through horizontal and vertical transmission. On the one hand, these microbes provide a rich source of several beneficial metabolites.
The present study reports on the isolation of fungal species from different in vitro medicinal plants (i.e., Breynia disticha major, Breynia disticha, Duranta plumieri, Thymus vulgaris, Salvia officinalis, Rosmarinus officinalis, and Ocimum basilicum l) cultures. These species were tested for their indole acetic acid (IAA) production capability. The most effective species for IAA production was that isolated from Thymus vulgaris plant (11.16 µg/mL) followed by that isolated from sweet basil plant (8.78 µg/mL). On screening for maximum IAA productivity, medium, "MOS + tryptophan" was chosen that gave 18.02 μg/mL. The macroscopic, microscopic examination and the 18S rRNA sequence analysis indicated that the isolate that given code T4 was identified as Neopestalotiopsis aotearoa (T4). The production of IAA by N. aotearoa was statistically modeled using the Box-Behnken design and optimized for maximum level, reaching 63.13 µg/mL. Also, IAA extract was administered to sweet basil seeds in vitro to determine its effect on plant growth traits. All concentrations of IAA extract boosted germination parameters as compared to controls, and 100 ppm of IAA extract exhibited a significant growth promotion effect for all seed germination measurements.
The IAA produced from N. aotearoa (T4) demonstrated an essential role in the enhancement of sweet basil (Ocimum basilicum) growth, suggesting that it can be employed to promote the plant development while lowering the deleterious effect of using synthetic compounds in the environment.
植物组织培养过程中的微生物生长是一个常见问题，会导致植物微繁殖系统的重大损失。这些内生微生物中的大多数都具有通过水平和垂直传播繁殖的能力。一方面，这些微生物提供了多种有益代谢物的丰富来源。
本研究报告了从不同离体药用植物（即 Breynia disticha major、Breynia disticha、Duranta plumieri、Thymus vulgaris、Salvia officinalis、Rosmarinus officinalis 和 Ocimum basilicum l）培养物中分离真菌物种的情况。这些物种的吲哚乙酸（IAA）产生能力进行了测试。从 Thymus vulgaris 植物中分离出的最有效产生 IAA 的物种（11.16 µg/mL），其次是从甜罗勒植物中分离出的（8.78 µg/mL）。在筛选最大 IAA 生产力时，选择了“MOS+色氨酸”培养基，可产生 18.02 µg/mL。宏观、微观检查和 18S rRNA 序列分析表明，给定代码 T4 的分离物被鉴定为 Neopestalotiopsis aotearoa（T4）。使用 Box-Behnken 设计对 N. aotearoa 产生的 IAA 进行了统计建模，并对最大水平进行了优化，达到 63.13 µg/mL。此外，将 IAA 提取物施用于离体甜罗勒种子，以确定其对植物生长特性的影响。与对照相比，IAA 提取物的所有浓度均能促进发芽参数，100 ppm 的 IAA 提取物对所有种子发芽测量均表现出显著的促进生长作用。
从 Neopestalotiopsis aotearoa（T4）中产生的 IAA 对甜罗勒（Ocimum basilicum）生长具有重要作用，表明它可以在促进植物发育的同时降低环境中使用合成化合物的有害影响。
