通讯机构：
[Huang, Y ] N;[Zhang, MH ] C;Cent South Univ Forestry & Technol, Coll Landscape & Architecture, Changsha 410004, Peoples R China.;Nanning Univ, Coll Art & Design, Nanning 530200, Peoples R China.
关键词：
Tree peony;Root rot;Pathogenic fungi;Biological control;Biocontrol bacteria;Synthetic consortium
摘要：
Tree peony (Paeonia suffruticosa), a traditional Chinese cultivated flowering shrub and a prominent landscaping plant, is subject to root rot. The key symptoms of root rot include black roots and the yellowing of leaves. Biological control is an effective and eco-friendly strategy for managing this disease. This study focused on the isolation, identification, and biological control of the pathogens causing peony root rot. Utilizing tissue isolation, pathogenicity determination, and rDNA-ITS sequence analysis, Fusarium solani and Fusarium oxysporum were determined to be the primary causal agents of peony root rot. Illumina MiSeq high-throughput sequencing of 16 s-rDNA was used to investigate and characterize bacterial community structure and diversity in healthy and diseased peony roots, rhizosphere, and bulk soil. Results indicated that the presence of pathogenic fungi influences the structure of the rhizosphere bacterial community and that peony roots exhibit a strong selective effect on root bacterial colonization. Variations in the composition of the endophytic microbial community in healthy and diseased roots exceeded the variation in the rhizosphere. Proteobacteria and Actinobacteria are the dominant taxa in the rhizosphere and among root endophytes, comprising 90-96 % of the bacterial microbiota. The rhizosphere of healthy plants exhibits a significant enrichment in Proteobacteria (79.6 %) and Actinobacteria (14.9 %), while root endophytes in healthy plats exhibit enrichment in Proteobacteria (83.5 %). In contrast, the rhizosphere and root endophytes in diseased plants are abundant in Proteobacteria (69 % and 66.1 %, respectively). Notably, nine strains of biocontrol bacteria were isolated. Three synthetic bacterial consortia were then constructed based on inhibitory assays and the dissolving rates of phosphorus and potassium exhibited by the candidate bacteria. The synthetic bacterial consortia were evaluated for biocontrol and growth promotion properties. The constructed synthetic consortium with the best performance reduced the average morbidity and mortality of treated plants by 27.59 % and 55.56 %, respectively, compared to the untreated control. In summary, synthetic bacterial consortium I (SCI) exhibited the best disease control and growth-promoting effects on tree peony. Using a synthetic bacterial consortium represents a new and novel approach to the biological control of peony root rot.
通讯机构：
[Yongyi Cui; Ping Luo] C;Collaborative Innovation Center for Efficient and Green Production of Agriculture in Mountainous Areas of Zhejiang Province, College of Horticulture Science, Zhejiang A & F University, Hangzhou, Zhejiang 311300, China
作者机构：
[Xijun H.; Wen X.; Xiaoli W.] College of Landscape Architecture, Central South University of Forestry and Technology, Changsha, 410004, China;Hunan Research Center of Engineering Technology for Utilization of Environmental, Resources Plant,Central South University of Forestry and Technology, Changsha, 410004, China;Guizhou Agriculture Career Academy, Guiyang, 551400, China;[Xiaoling J.] College of Landscape Architecture, Central South University of Forestry and Technology, Changsha, 410004, China, Hunan Research Center of Engineering Technology for Utilization of Environmental, Resources Plant,Central South University of Forestry and Technology, Changsha, 410004, China;[Yaping Z.] College of Landscape Architecture, Central South University of Forestry and Technology, Changsha, 410004, China, Guizhou Agriculture Career Academy, Guiyang, 551400, China
通讯机构：
[Xijun, H.] C;College of Landscape Architecture, China
摘要：
Rhododendron is universally known for its showy flower, and Rhododendron latoucheae Franch. is an adaptable and wide altitude range species of Rhododendron, with beautiful fragrant flowers and medicinal functions. However, genetic studies of Rhododendron have been hindered by limited genomic resources and genetic markers. In this study, a large dataset composed of 80,660 unigenes derived from the R. latoucheae transcriptome was assembled. Among these unigenes, 34,867 unigenes (43.22%) were annotated against public protein databases. In addition, a total of 14,415 EST-SSRs were identified from 16,019 unigene sequences with an average of one SSR per 2.87 kb. Di-nucleotide SSRs were the most abundant motif (80.03%), followed by tri- (18.82%), tetra- (0.91%), penta- (0.13%), and hexa-nucleotide (0.11%) repeats. Further, 200 primer pairs with more than six tandem repeats were selected, out of which 58 primer pairs amplified successfully and revealed polymorphism among six Rhododendron species. Among these 58 primer pairs, 37 primer pairs were polymorphic in 37 Rhododendron species and 30 R. latoucheae individuals from two national Chinese populations. A total of 382 alleles were identified, with an average of 10.3 alleles per locus. The phylogenetic tree, genetic structure analysis, and principal coordinate analysis demonstrated that major clusters corresponded to known phylogenetic trees and geographic distribution. These transcriptome data will facilitate gene discovery and functional genomic studies in Rhododendron, and the newly developed EST-SSR markers can be applied across multiple Rhododendron species and used for the evaluation of genetic relationships in Rhododendron.
