[Effects of temperature and humidity on infection of Fusarium oxysporum in seedlings of Salvia miltiorrhiza].

Wilt disease is a major disease of cultivated Salvia miltiorrhiza, which is caused by Fusarium oxysporum. Since the infection process of F. oxysporum in plants is affected by environment factors, this study was conducted to reveal the relationship between disease severity and concentration of the pathogen in plants in the infection process of F. oxysporum in seedlings of S. miltiorrhiza by pot experiments and to reveal the effects of temperature and humidity on the infection process. The results showed that, after inoculation of S. miltiorrhiza seedlings with F. oxysporum, the pathogen in different parts was detected at different time, and it was first detected in substrates. With the continuous propagation of the pathogen(4-5 d), it gradually infected the roots and stems of the seedlings, and the plants had yellowing leaves and withering. The number of the pathogen reached the maximum in each part after 7-8 d, and then gradually decreased in the later stage of the disease. The concentration of the pathogen in substrates, roots and stems of S. miltiorrhiza showed a trend of decreasing after increasing with the aggravation of the disease and reached the maximum in the samples of moderate morbidity, while the concentration in the samples of severe morbidity decreased. In addition, the infection of F. oxysporum in seedlings of S. miltiorrhiza was affected by temperature and humidity. The suitable temperature was 25-30 ℃ and the suitable humidity was 80%-90%. This study could provide guidance for the experiments on pathogenicity of F. oxysporum, screening of biocontrol bacteria and controlling of wilt.

[Pathogenicity and induced systemic resistance of Fusarium oxysporum and Verticillium dahlia to Salvia miltiorrhiza].

Salvia miltiorrhiza is a commonly used bulk medicinal material in China. Due to the increasing demand in recent years, the planting area is expanding. In the artificial cultivation of S. miltiorrhiza, continuous cropping obstacles are prominent, which has seriously restrained the growth of S. miltiorrhiza, resulted in serious root diseases, and affected the yield and quality of medicinal materials. The pathogen infection can induce plant resistance. Previously, this research group isolated Fusarium oxysporum and Verticillium dahlia from the roots of diseased S. miltiorrhiza. In this study, 7 days after inoculation of S. miltiorrhiza with F. oxysporum(Foc group) and V. dahlia(Vd group), the incidence rates in S. miltiorrhiza were 48% and 26%, respectively. Both the two pathogens significantly reduced the aboveground biomass of S. miltiorrhiza. Five days after inoculation, the activities of defensive enzymes, such as peroxidase(POD), phenylalanine ammonia-lyase(PAL), superoxide dismutase(SOD), and polyphenol oxidase(PPO) reached the peak. The enzyme activity of the Foc group was significantly higher than that of the Vd group. Three days after inoculation, the expression of defense genes SmPDF2.1 and SmPR10 peaked and then decreased. The results showed that F. oxysporum and V. dahlia showed pathogenicity to S. miltiorrhiza and could strongly induce systemic resistance. In terms of the above indexes, F. oxysporum was superior to V. dahlia.

[Effects of interaction between ubiquitin/26S proteasome inhibitor MG132 and mycorrhiza on growth and effective components of Salvia miltiorrhiza].

Ubiquitin/26 S proteasome system(UPS) is one of the main ways to regulate the degradation of proteins in plants, and plays an important role in physiological processes such as secondary metabolism and plant hormone signal transduction. As indicated recently, UPS is involved in plant-microbe interactions, and presumably regulates arbuscular mycorrhizal symbiosis to affect its effects. This study investigated the effects of interaction between Cbz-leu-leu-leucinal(MG132) and the mycorrhiza on the growth and effective components of Salvia miltiorrhiza by inoculation with Glomus intraradices and spraying MG132 solution. The results showed that the inoculation with G. intraradices could promote the growth of S. miltiorrhiza, increase the accumulation of effective components in the aerial and underground parts, and decrease the relative expression level of JMT. Additionally, MG132 could strengthen the growth-promoting effect of G. intraradices. As compared with the control group, the inoculation with G. intraradices could significantly increase aerial and underground fresh weights by 267% and 95%, respectively, under the treatment with MG132 spraying, while under the MG132 spraying-free condition, the increase was 195% and 32%, respectively. Meanwhile, MG132 spraying could enhance the promotion of mycorrhizal fungi on the accumulation of active components of S. miltiorrhiza. On the other hand, regardless of inoculation with G. intraradices or not, MG132 treatment could promote the root division of S. miltiorrhiza, reduce the content of effective components in the aerial parts, and increase the content in the underground part. The inoculation with G. intraradices could alleviate the inhibitory effect of MG132 on the accumulation of effective components in the aerial part of S. miltiorrhiza. The results show that arbuscular mycorrhizal fungi(AMF) can promote the growth of S. miltiorrhiza and the accumulation of effective components, and MG132 treatment can strengthen such promotion effect, which lays a foundation for the application of MG132 in the mycorrhizal cultivation of S. miltiorrhiza in the future.

[Effect of different fungicides on efficiency of mycorrhizal symbiosis on Salvia miltiorrhiza].

Arbuscular mycorrhizal fungi provided is beneficial to Salvia miltiorrhiza for increasing yield, promoting the accumulation of active ingredients, and alleviating S. miltiorrhiza disease etc. However, the application of fungicides will affect the benefit of arbuscular mycorrhizal fungi and there is little research about it. This article study the effect of four different fungicides: carbendazim, polyoxin, methyl mopazine, and mancozeb on mycorrhiza benefit to S. miltiorrhiza by the infection intensity of arbuscular mycorrhizal fungi, the growth of S. miltiorrhiza, and the content of active ingredients. RESULTS:: showed that different fungicides had different effects. The application of mancozeb had the strongest inhibitory effect on the mycorrhizal benefit to S. miltiorrhiza. Mancozeb significantly reduced the mycorrhizal colonization and the beneficial effect of arbuscular mycorrhizal fungi on the growth and the accumulation of active components of S. miltiorrhiza. The application of polyoxin had no significant effect on mycorrhizal colonization. Instead, it had a synergistic effect with the mycorrhizal benefit to promoting the growth and accumulation of rosmarinic acid of S. miltiorrhiza. The inhibitory strengths of four fungicides are: mancozeb>thiophanate methyl, carbendazim>polyoxin. Therefore, we recommend applying biological fungicides polyoxin and avoid applying chemical fungicides mancozeb for disease control during mycorrhizal cultivation of S. miltiorrhiza.