Progress on research of tissue culture of Bletilla striata

Recombination of endophytic bacteria in asexual plant Ligusticum chuanxiong Hort. caused by transplanting

Background

Long-term asexual reproduction can easily lead to the degradation of plant germplasm, serious diseases and insect pests, reduction of production and even catastrophic crop failure. "Mountain Breeding and Dam Cultivation" is the main cultivation mode of Ligusticum chuanxiong Hort., which successfully avoided the germplasm degradation caused by long-term asexual reproduction. The recombination of endophytic fungi of L. chuanxiong caused by off-site transplantation was considered to be an important reason for its germplasm rejuvenation. However, whether bacteria have the same regularity is not yet known.

Methods

In this study, we carried out the experiment of cultivating propagation materials of L. chuanxiong in different regions and transplanting them to the same region. High-throughput sequencing was performed to analyze the bacterial communities in L. chuanxiong and its soil.

Results

The results showed that after transplanting, the plant height, tiller number, fresh weight, etc. of L. chuanxiong in mountainous areas were significantly higher than those in dam areas. At the same time, significant changes had taken place in the endophytic bacteria in reproductive material stem nodes (Lingzi, abbreviated as LZ). The diversity and abundance of bacteria in dam area LZ (YL) are significantly higher than those in mountainous area LZ (ML). The relative abundance of bacteria such as Xanthobacteraceae, Micromonosporaceae, Beijerinkiaceae, Rhodanobacteria, in ML is significantly higher than YL, mainly classified in Proteobateria and Actinobacteriota. In addition, the abundance advantage of Actinobacteriota still exists in MY (underground mature rhizomes obtained by ML). Meanwhile, the bacterial community was different in different area of transplanting. The diversity of bacterial communities in dam soil (YLS) is significantly higher than that in mountain soil (MLS). MLS had more Acidobacteriota than YLS. Comparative analysis showed that 74.38% of bacteria in ML are found in MLS, and 87.91% of bacteria in YL are found in YLS.

Conclusions

We can conclude that the community structure of endophytic bacteria recombined after the transplantation of L. chuanxiong, which was related to the bacterial community in soils. Moreover, after transplanting in mountainous areas, LZ accumulated more potentially beneficial Actinobacteriota, which may be an important reason for promoting the rejuvenation of germplasm in L. chuanxiong. However, this hypothesis requires more specific experiments to verify. This study provided a new idea that off-site transplanting may be a new strategy to restore vegetative plant germplasm resources.