ABSTRACT
DNA marked-assisted selection of medicinal plants accelerated the breeding and promotion of new cultivars, and guaranteed the healthy development of Chinese medicinal materials industry. The first disease-resistant cultivar of notoginseng, namely "Miaoxiang Kangqi 1", served as the object of study. We evaluated the Kangqi's resistance of seeds, seedlings and root against the pathological bacteria (Fusarum oxysporum) of root rot. Compared to the traditional cultivars, the disease index of notoginseng seeds declined by 52.0% after inoculation for seven days; the death rate of seedlings and disease index of root respectively decreased by 72.1% and 62.4% after inoculation for 25 days. Additionally, the growth inhibition ratio of notoginseng seeds and seedlings declined after inoculation. The seeds, seedlings and roots of "Miaoxiang Kangqi 1" showed significantly resistant to root rot. The evaluation of disease-resistance of Kangqi provided the basis for the popularization of new cultivar and guaranteed the favoring conduct of notoginseng pollution-free cultivation.
ABSTRACT
DNA marker-assisted selection of medicinal plants is based on the DNA polymorphism, selects the DNA sequences related to the phenotypes such as high yields, superior quality, stress-resistance and so on according to the technologies of molecular hybridization, polymerase chain reaction and high-throughput sequencing, and assists the breeding of new cultivars. This study bred the first disease-resistant cultivar of notoginseng "Miaoxiang Kangqi 1" using the technology of DNA marker-assisted selection of medicinal plants and systematic breeding. The disease-resistant cultivar of notoginseng contained 12 special SNPs based on the analysis of Restriction-site Associated DNA Sequencing (RAD-Seq). Among the SNP (record_519688) was related to the root rot-resistant characteristics, which indicated this SNP could serve as genetic markers of disease-resistant cultivars and assist the systematic breeding. Compared to the conventional cultivated cultivars, the incidence rate of root-rot and rust-rot in notoginseng seedlings decreased by 83.6% and 71.8%, respectively. The incidence rate of root-rot respectively declined by 43.6% and 62.9% in notoginseng cultivation for 2 and 3 years compared with those of the conventional cultivated cultivars. Additionally, the potential disease-resistant groups were screened based on the relative SNP, and this model enlarged the target groups and advanced the breeding efficiency. DNA marker-assisted selection of medicinal plants accelerated the breeding and promotion of new cultivars, and guaranteed the healthy development of Chinese medicinal materials industry.
ABSTRACT
Continuous cropping obstacles resulted in the yield losses of Panax ginseng, and affected the development of ginseng industry. Soil fungal communities participated in the key ecological process, and their changes of diversity and composition were related to the continuous cropping obstacles. We analyzed the changes of fungal diversity and composition in the rhizosphere of ginseng using the high-throughput sequencing method, stated the effects of ginseng cultivation on the micro-ecology, and provided effective strategies for overcoming continuous cropping obstacles. Compared to those of the forest soils, the fungal diversity of ginseng rhizosphere soils was increased, and the increasing trends were declined with an increasing years of ginseng cultivation; the relative abundance of Sordariomycetes, Alatospora, Eurotiomycetes, Leotiomycetes, Saccharomycetes, Mucorales and Pezizomycetes were increased in the rhizosphere of ginseng. Pearson's correlation index indicated that soil chemical perporties affected the relative abundance of fungal communities. pH was significantly related to the relative abundance of Dothideomycetes and Alatospora; the content of available potassium was markedly associated with the relative abundance of Dothideomycetes, Alatospora and Mucorales; the content of total nitrogen was significant correlation with the relative abundance of Sordariomycetes and Mucorales. These results indicated that fertilization was one of pivotal factors affecting the rhizosphere micro-ecology of ginseng, and optimization of fertilization system was an effective method to overcome continuous cropping obstacles.