Chen Hai-Min, Wu Hong-Xia, He Xiao-Yi, Zhang Hai-Hua, Miao Fang, Liang Zong-Suo
College of Life Sciences, Northwest A&F University Yangling 712100, China Key Laboratory of Plant Secondary Metabolism and Regulation of Zhejiang Province, College of Life Sciences and Medicine, Zhejiang Sci-Tech University Hangzhou 310018, China.
Key Laboratory of Plant Secondary Metabolism and Regulation of Zhejiang Province, College of Life Sciences and Medicine, Zhejiang Sci-Tech University Hangzhou 310018, China.
Zhongguo Zhong Yao Za Zhi. 2020 Jan;45(1):65-71. doi: 10.19540/j.cnki.cjcmm.20191113.101.
The interaction of endophytes and host plant is an effective mean to regulate the growth and secondary metabolism of medicinal plants. Here we want to elucidate the effects and mechanism of Phoma herbarum D603 on the root development and tanshinone synthesis in root of Salvia miltiorrhiza by endophyte-plant coculture system. The mycelium of P. herbarum D603 was colonized in the root tissue space, and formed a stable symbiotic relationship with host plant. The in vitro activities analysis showed that the concentration of IAA produced by D603 can reach(6.45±0.23) μg·mL(-1), and this strain had some abilities of phosphorus solubilization and siderophore production activities. The coculture experiment showed that strain D603 can significantly promote the synthesis and accumulation of tanshinones in the root of S. miltiorrhiza, in which after 8 weeks of treatment with D603, the content of tanshinone Ⅱ_A in the roots reached up to(1.42±0.59) mg·g(-1). By the qRT-PCR analysis results, we found that D603 could improve the expression levels of some key genes(DXR, DXS, GGPP, HMGR, CPS) of tanshinone biosynthesis pathway in host plant S. miltiorrhiza, but the promoting effect mainly occurred in the early stage of the interaction, and the enzyme activity level decreased in varying degrees of the later stage. In summary, seed-associated endophyte P. herbarum D603 can promote the growth and root development of S. miltiorrhiza by producing hormones, promoting nutrient absorption and siderophore production, and promote the synthesis and accumulation of tanshinones by regulating the expression level of key genes in the synthetic pathway in S. miltiorrhiza.
内生菌与宿主植物的相互作用是调节药用植物生长和次生代谢的有效手段。在此，我们想通过内生菌 - 植物共培养系统阐明草本茎点霉D603对丹参根发育和丹参酮合成的影响及机制。草本茎点霉D603的菌丝定殖于根组织间隙，并与宿主植物形成稳定的共生关系。体外活性分析表明，D603产生的IAA浓度可达(6.45±0.23) μg·mL(-1)，且该菌株具有一定的解磷能力和产铁载体活性。共培养实验表明，菌株D603能显著促进丹参根中丹参酮的合成与积累，其中用D603处理8周后，根中丹参酮Ⅱ_A含量高达(1.42±0.59) mg·g(-1)。通过qRT-PCR分析结果，我们发现D603能提高宿主植物丹参中丹参酮生物合成途径一些关键基因（DXR、DXS、GGPP、HMGR、CPS）的表达水平，但促进作用主要发生在相互作用的早期，后期酶活性水平有不同程度下降。综上所述，种子相关内生菌草本茎点霉D603可通过产生激素、促进养分吸收和产铁载体来促进丹参的生长和根发育，并通过调节丹参合成途径中关键基因的表达水平来促进丹参酮的合成与积累。
