AUTHOR=Li Wei , Hu Xue-Yi , Zhu Cheng-Shang , Guo Shao Xia , Li Min 

TITLE=Control effect of root exudates from mycorrhizal watermelon seedlings on Fusarium wilt and the bacterial community in continuously cropped soil

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 14 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1225897

DOI=10.3389/fpls.2023.1225897

ISSN=1664-462X

ABSTRACT=Watermelon (Citrullus lanatus) is susceptible to wilt disease caused by Fusarium oxysporum f. sp niveum (FON). AMF colonization alleviates watermelon wilt and regulates the composition of root exudates. Root exudates of watermelon inoculated with AMF (Funeliformis mosseae or Glomus versiformme) were collected in this study. The root exudates collected by control plants and mycorrhizal plants were then used to irrigate watermelon in continuous cropping soil. The effects of root exudates on watermelon growth and antioxidant enzyme activity, as well as the control effect on FON were evaluated, and changes in rhizosphere soil enzyme activities and soil bacterial community composition were analyzed. Mycorrhizal watermelon root exudates promoted the growth of watermelon seedlings and increased soil enzyme activities, actinomyces, and the quantity of bacteria in rhizosphere soil. The proportion of Proteobacteria and Bacteroides was decreased, and the proportion of Actinobacteria, Firmicutes, and Chloroflexi in rhizosphere soil was increased when the seedlings were watered with high concentrations of mycorrhizal root exudates. The dominant bacterial genera in rhizosphere soil were Kaistobacter, Rhodanobacter, Thermomonas, Devosia, and Bacillus. The root exudates of mycorrhizal watermelon could reduce the disease index of Fusarium wilt by 6.7-30%. In conclusion, mycorrhizal watermelon root exudates could promote watermelon growth, alter the composition of bacteria in rhizosphere soil, improve the rhizosphere soil environment, and increase the resistance of watermelon to Fusarium wilt. Five ml/L of watermelon root exudates inoculated with F. mosseae had the strongest inhibitory effect on watermelon Fusarium wilt.