Cross Interaction Between Ilyonectria mors-panacis Isolates Infecting Korean Ginseng and Ginseng Saponins in Correlation with Their Pathogenicity
Cross Interaction Between Ilyonectria mors-panacis Isolates Infecting Korean Ginseng and Ginseng Saponins in Correlation with Their Pathogenicity
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DOI：
10.1094/phyto-05-16-0210-r
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发表时间：
2017-05-01
期刊：
影响因子：
3.2
通讯作者：
Yang, Deok-Chun
中科院分区：
文献类型：
--
作者：
Farh, Mohamed El-Agamy;Kim, Yeon-Ju;Yang, Deok-Chun
Ilyonectria mors-panacis 属于 I. radiicicola 复合种，在亚洲和北美会导致人参根腐病和再植失败。这项工作的目的是利用分子方法鉴定感染高丽参的 L mors-panacis，并与其他已鉴定的 Ilyonectria 物种相比，研究它们的攻击性是否取决于它们通过 β-葡萄糖苷酶代谢人参皂苷（人参皂苷）的能力。从培养物保藏中心收集或直接从感染的根中分离出 14 个分离株，主要根据组蛋白 H3 (HIS H3) 序列进行鉴定。其中，6个分离株被鉴定为I. mors-panacis，其他分离株被鉴定为I.Robusta和I.leucospermi。致病性测试证实，I. mors-panacis 分离株的侵袭性明显高于 I.Robusta 和 I. leucospermi。受I. mors-panacis感染的根中主要人参皂苷显着减少，而感染其他物种的根中主要人参皂苷显着增加。在体外，测试了分离株的敏感性和代谢总主要人参皂苷（Total MaG）、原人参二醇型主要人参皂苷（PPD-型MaG）和原人参三醇型主要人参皂苷（PPT-型MaG）的能力。出乎意料的是，三种不同人参皂苷组分上的 I. mors-panacis 分离株的生长速率和代谢能力显着较低，而 I.robusta 和 I. leucospermi 的生长速率和代谢能力在 PPT 型 MaG 和 Total MaG 组分上显着降低，而在 PPD 型 MaG 组分上不受影响。我们的结果表明，主要人参皂苷，尤其是 PPT 型皂苷，具有抗真菌作用，并且可能在 Ilyonectria 物种入侵期间（尤其是弱物种）干预人参防御。此外，I. mors-panacis 的致病性可能依赖于其降低皂苷含量的能力。然而，这种减少是由排毒还是其他方法引起的仍不清楚。
Ilyonectria mors-panacis belongs to I. radicicola species complex and causes root rot and replant failure of ginseng in Asia and North America. The aims of this work were to identify L mors-panacis that infect Korean ginseng using molecular approaches and to investigate whether their aggressiveness depends on their ability to metabolize ginseng saponins (ginsenosides) by their beta-glucosidases, in comparison with other identified Ilyonectria species. Fourteen isolates were collected from culture collections or directly isolated from infected roots and mainly identified based on histone H3 (HIS H3) sequence. Among them, six isolates were identified as I. mors-panacis while others were identified as I. robusta and I. leucospermi. The pathogenicity tests confirmed that the isolates of I. mors-panacis were significantly more aggressive than I. robusta and I. leucospermi. The major ginsenosides in I. mors-panacis-infected roots were significantly reduced while significantly increased in those infected with other species. In vitro, the isolates were tested for their sensitivity and ability to metabolize the total major ginsenosides (Total MaG), protopanaxadiol-type major ginsenosides (PPD-type MaG), and protopanaxatriol-type major ginsenosides (PPT-type MaG). Unexpectedly, the growth rate and metabolic ability of I. mors-panacis isolates were significantly low on the three different ginsenoside fractions while those of I. robusta and I. leucospermi were significantly reduced on PPT-type MaG and Total MaG fractions and not affected on PPD-type MaG fraction. Our results indicate that major ginsenosides, especially PPT-type, have an antifungal effect and may intervene in ginseng defense during Ilyonectria species invasion, in particular the weak species. Also, the pathogenicity of I. mors-panacis may rely on its ability to reduce saponin content; however, whether this reduction is caused by detoxification or another method remains unclear.