Different Response Mechanisms of Rhizosphere Microbial Communities in Two Species of Amorphophallus to Pectobacterium carotovorum subsp. carotovorum Infection

Abstract

Soft rot is a widespread, catastrophic disease caused by <i>Pectobacterium carotovorum</i> subsp. <i>carotovorum</i> (Pcc) that severely damages the production of <i>Amorphophallus</i> spp. This study evaluated the rhizosphere bacterial and fungal communities in <i>Pcc</i>-infected and uninfected plants of two species of <i>Amorphophallus</i>, <i>A. muelleri</i> and <i>A. konjac</i>. Principal component analysis showed that the samples formed different clusters according to the <i>Pcc</i> infection status, indicating that <i>Pcc</i> infection can cause a large number of changes in the bacterial and fungal communities in the <i>Amorphophallus</i> spp. rhizosphere soil. However, the response mechanisms of <i>A. muelleri</i> and <i>A. konjac</i> are different. There was little difference in the overall microbial species composition among the four treatments, but the relative abundances of core microbiome members were significantly different. The relative abundances of Actinobacteria, Chloroflexi, Acidobacteria, Firmicutes, <i>Bacillus</i>, and <i>Lysobacter</i> were lower in infected <i>A. konjac</i> plants than in healthy plants; in contrast, those of infected <i>A. muelleri</i> plants were higher than those in healthy plants. For fungi, the relative abundances of Ascomycota and <i>Fusarium</i> in the rhizosphere of infected <i>A. konjac</i> plants were significantly higher than those of healthy plants, but those of infected <i>A. muelleri</i> plants were lower than those of healthy plants. The relative abundance of beneficial <i>Penicillium</i> fungi was lower in infected <i>A. konjac</i> plants than in healthy plants, and that of infected <i>A. muelleri</i> plants was higher than that of healthy plants. These findings can provide theoretical references for further functional research and utilization of <i>Amorphophallus</i> spp. rhizosphere microbial communities in the future.