Abstract
Securinega suffruticosa (Pall.) Rehd is an excellent natural secondary shrub in the Shell Islands of Yellow River Delta. The roots of S. suffruticosa have high medicinal value and are used to treat diseases, such as neurasthenia and infant malnutrition. Any organism that is isolated from this species is of immense interest due to its potential novel bioactive compounds. In this research, the distribution and diversity of culturable endophytic fungi in S. suffruticosa were studied, and the endophytic fungi with antimicrobial activity were screened. A total of 420 endophytic fungi isolates were obtained from the S. suffruticosa grown in Shell Islands, from which 20 genera and 35 species were identified through morphological and internal transcribed spacer (ITS) sequence analyses. Chaetomium, Fusarium, Cladosporium, and Ceratobasidium were the dominant genera. The high species richness S (42), Margalef index D' (5.6289), Shannon-Wiener index H' (3.1000), Simpson diversity index Ds (0.9459), PIE index (0.8670), and evenness Pielou index J (0.8719) and a low dominant index λ (0.0541) indicated the high diversity of endophytic fungi in S. suffruticosa, the various species of endophytic fungi with obvious tissue specificity. The inhibition percentages of the 12 species of such endophytic fungi against Colletotrichum siamense were 3.6%-26.3%. C. globosum, Fusarium sp.3, and C. ramotenellum had a high antibacterial activity against Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. The Minimum Inhibitory Concentration (MIC) and the Minimum Bactericidal Concentration (MBC) were between 0.5 mg/mL and 2 mg/mL. Alkaloid content detection indicated that endophytic fungi had a high alkaloid content, whereas the alkaloid contents of C. globosum and Fusarium sp.3 reached 0.231% and 0.170%, respectively. Members belonging to the endophytic fungal community in the S. suffruticosa of Shell Islands that may be used as antagonists and antibacterial agents for future biotechnology applications were identified for the first time.
Highlights
The Shell Islands of Yellow River Delta is one of the three largest old shell islands in the world; it is mainly formed by the shells and debris of shellfish living in the intertidal zone after their death, which are transported by waves and piled near the high tide line [1,2]
DNA extraction, PCR amplification, target bands purification and sequencing were performed on the endophytic fungal isolates from S. suffruticosa
The isolates Y1, Y4, Y6, Y7, and Y8 and Fusarium solani were clustered on the same branch, with 68% support rating
Summary
The Shell Islands of Yellow River Delta is one of the three largest old shell islands in the world; it is mainly formed by the shells and debris of shellfish living in the intertidal zone after their death, which are transported by waves and piled near the high tide line [1,2]. Pharmacological studies have shown that S. suffruticosa can promote blood circulation, relax the muscles and tendons, invigorate the spleen and kidney, and relieve rheumatic pains This shrub is effective for the treatment of neurasthenia, facial nerve paralysis, post-polio syndrome, dizziness, deafness, narcolepsy, impotence, and acute liver injury, and other diseases [7,8,9,10]. The fungi from the coastal saline soil in the Yellow River Delta grow in habitats under unique conditions due to the activation of metabolic pathways and the synthesis of distinct unknown molecules [12] The production of these compounds supports the adaptation and survival of fungi in special ecosystems [13]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
