LXG Toxins of Bacillus Velezensis Mediate Contact-Dependent Inhibition in a T7SS-Dependent Manner to Enhance Rhizosphere Adaptability

被引：0

作者：

Shu, Xia ^{[1
,2
]}

Sun, Xiting ^{[1
]}

Wang, Kesu ^{[3
]}

Duan, Yan ^{[3
]}

Liu, Yunpeng ^{[1
]}

Zhang, Ruifu ^{[1
,3
]}

机构：

[1] Chinese Acad Agr Sci, Inst Agr Resources & Reg Planning, State Key Lab Efficient Utilizat Arid & Semiarid A, Beijing 100081, Peoples R China

[2] Huazhong Agr Univ, Coll Life Sci & Technol, Wuhan 430070, Peoples R China

[3] Nanjing Agr Univ, Natl Engn Res Ctr Organ Based Fertilizers, Jiangsu Collaborat Innovat Ctr Solid Organ Waste R, Jiangsu Prov Key Lab Organ Solid Waste Utilizat, Nanjing 210095, Peoples R China

来源：

INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES | 2025年 / 26卷 / 06期

基金：

中国国家自然科学基金;

关键词：

Bacillus velezensis; T7SS; LXG toxins; contact-dependent inhibition; rhizosphere competition; biofilm; SECRETION; GROWTH; SQR9;

D O I：

10.3390/ijms26062592

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Rhizosphere bacteria always compete intensely for ecological niches, employing various strategies to inhibit the growth of microbial competitors. One such strategy, contact-dependent inhibition (CDI), involves the direct delivery of toxic proteins into competing neighboring bacteria by a secretion system, leading to the inhibition of their growth. However, the ecological function of CDI competition in the natural environment remains unclear. In this study, we examined the role of the type VII secretion system (T7SS) substrate LXG domain-containing protein in the rhizobacterium Bacillus velezensis SQR9 and found that SQR9 encodes LXG toxins mediate contact-dependent inhibition against other Bacillus strains in biofilms. Transcriptional analysis revealed that the expression of these lxg genes is induced by root exudates and positively correlates with that of the T7SS gene cluster. We further confirmed that the survival of the mutants deficient of the LXG toxins was significantly decreased in natural soil. These findings highlight the critical role of T7SS and its substrate LXG toxins in competition of Bacillus species in the rhizosphere, providing new insights into the ecological importance of CDI in natural environments.

引用

页数：14