Open AccessPlant growth promoting endophyte Burkholderia contaminans NZ antagonizes phytopathogen Macrophomina phaseolina through melanin synthesis and pyrrolnitrin inhibition
Author(s) -
Nazia Zaman,
Umar Faruq Chowdhury,
Rifath Nehleen Reza,
Farhana Tasnim Chowdhury,
Md. Mizanur Rahman Sarker,
Md. Motaher Hossain,
Md. Ahedul Akbor,
Al Amin,
Mohammad Riazul Islam,
Haseena Khan
Publication year - 2021
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0257863
Subject(s) - macrophomina phaseolina , microbiology and biotechnology , biology , burkholderia , bacteria , botany , genetics
The endophytic bacterium Burkholderia contaminans NZ was isolated from jute, which is an important fiber-producing plant. This bacterium exhibits significant growth promotion activity in in vivo pot experiments, and like other plant growth-promoting (PGP) bacteria fixes nitrogen, produces indole acetic acid (IAA), siderophore, and 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. B . contaminans NZ is considered to exert a promising growth inhibitory effect on Macrophomina phaseolina , a phytopathogen responsible for infecting hundreds of crops worldwide. This study aimed to identify the possibility of B . contaminans NZ as a safe biocontrol agent and assess its effectiveness in suppressing phytopathogenic fungi, especially M . phaseolina . Co-culture of M . phaseolina with B . contaminans NZ on both solid and liquid media revealed appreciable growth suppression of M . phaseolina and its chromogenic aberration in liquid culture. Genome mining of B . contaminans NZ using NaPDoS and antiSMASH revealed gene clusters that displayed 100% similarity for cytotoxic and antifungal substances, such as pyrrolnitrin. GC-MS analysis of B . contaminans NZ culture extracts revealed various bioactive compounds, including catechol; 9,10-dihydro-12’-hydroxy-2’-methyl-5’-(phenylmethyl)- ergotaman 3’,6’,18-trione; 2,3-dihydro-3,5- dihydroxy-6-methyl-4H-pyran-4-one; 1-(1,6-Dioxooctadecyl)- pyrrolidine; 9-Octadecenamide; and 2- methoxy- phenol. These compounds reportedly exhibit tyrosinase inhibitory, antifungal, and antibiotic activities. Using a more targeted approach, an RP-HPLC purified fraction was analyzed by LC-MS, confirming the existence of pyrrolnitrin in the B . contaminans NZ extract. Secondary metabolites, such as catechol and ergotaman, have been predicted to inhibit melanin synthesis in M . phaseolina . Thus, B . contaminans NZ appears to inhibit phytopathogens by apparently impairing melanin synthesis and other potential biochemical pathways, exhibiting considerable fungistatic activity.