Department of Biotechnology, Alagappa University, Science Campus, Karaikudi, Tamil Nadu, 630003, India.
Blaustein Center for Scientific Cooperation Postdoctoral Fellow @ French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Negev, Israel.
BMC Plant Biol. 2024 Sep 19;24(1):872. doi: 10.1186/s12870-024-05582-8.
Nilgirianthus ciliatus, extensively exploited for its pharmacological properties, is now classified as vulnerable. In vitro micropropagation offers a sustainable approach for ecological conservation and rational utilization of this biodiversity resource. This study aimed to reduce endophytes during in vitro propagation and isolating antimicrobial-resistant endophytes from N. ciliatus by employing various concentrations and exposure times of Plant Preservative Mixture (PPM). Optimal results were observed when nodal explants treated with 0.3% PPM for 8 h, followed by inoculation in Murashige and Skoog (MS) medium supplemented with 3 mg/L 6-benzylaminopurine (BAP) and 0.3% PPM. This protocol achieved 82% shoot regeneration with minimal endophytic contamination, suggesting that the duration of explant exposure to PPM significantly influences endophyte reduction. Two antimicrobial-resistant endophytes were isolated and identified as Bacillus cereus and Acinetobacter pittii through 16S rDNA sequencing. These endophytes exhibited plant growth-promoting characteristics, including amylolytic, proteolytic, lipolytic activities, indole-3-acetic acid production, phosphate solubilization, and stress tolerance. In vivo application of these endophytes as bioinoculants to N. ciliatus not only improved growth parameters but also significantly increased the levels of pharmacologically important compounds, squalene, and stigmasterol, as confirmed by High-performance thin-layer chromatography (HPTLC). This study demonstrates that PPM is a promising alternative for sustainable micropropagation of N. ciliatus. Furthermore, it highlights the potential of antimicrobial-resistant endophytes as bioinoculants to improve growth and medicinal value, offering a sustainable solution for conservation and large-scale cultivation of this species.
锡金报春广泛应用于药理学领域，现已被列为易危物种。体外微繁殖为生态保护和合理利用这种生物多样性资源提供了可持续的方法。本研究旨在通过使用不同浓度和暴露时间的植物防腐剂混合物（PPM）减少体外繁殖中的内生菌，并从锡金报春中分离出具有抗微生物特性的内生菌。当将节点外植体用 0.3%的 PPM 处理 8 小时，然后接种到添加 3mg/L 6-苄基氨基嘌呤（BAP）和 0.3%的 PPM 的 Murashige 和 Skoog（MS）培养基中时，观察到最佳结果。该方案以最小的内生污染实现了 82%的芽再生，表明外植体暴露于 PPM 的时间长短对内生菌的减少有显著影响。通过 16S rDNA 测序，从锡金报春中分离并鉴定出两种具有抗微生物特性的内生菌，分别为蜡状芽孢杆菌和醋酸钙不动杆菌。这些内生菌表现出植物生长促进特性，包括淀粉酶、蛋白酶、脂肪酶活性、吲哚-3-乙酸产生、磷酸盐溶解和应激耐受。将这些内生菌作为生物接种剂应用于锡金报春体内不仅改善了生长参数，而且还显著提高了具有药理重要性的化合物角鲨烯和豆甾醇的水平，这一点通过高效薄层层析（HPTLC）得到了证实。本研究表明，PPM 是可持续繁殖锡金报春的有前途的替代方法。此外，它还强调了具有抗微生物特性的内生菌作为生物接种剂的潜力，可以提高生长和药用价值，为保护和大规模种植该物种提供了可持续的解决方案。
