Metabolomic profiling and its association with the bio-efficacy of Aspergillus niger strain against Fusarium wilt of guava

Abstract

Bio-control agents are the best alternative to chemicals for the successful management of plant diseases. The fungus Aspergillus niger is known to produce diverse metabolites with antifungal activity, attracting researchers to exploit it as a bio-control agent for plant disease control. In the present study, 11 A. niger strains were isolated and screened for their antagonism against the guava wilt pathogen under in vitro and in planta conditions. Strains were identified morphologically and molecularly by sequencing the internal transcribed spacer (ITS), β-tubulin, and calmodulin genes. The strains were evaluated through dual culture, volatile, and non-volatile methods under an in vitro study. AN-11, AN-6, and AN-2 inhibited the test pathogen Fusarium oxysporum f. sp. psidii (FOP) at 67.16%, 64.01%, and 60.48%, respectively. An in planta study was conducted under greenhouse conditions with 6 months old air-layered guava plants (var. Allahabad Safeda) by pre- and post-inoculation of FOP. The AN-11 strain was found to be effective under both pre- and post-inoculation trials. Furthermore, gas chromatography–mass spectrometry (GC–MS) analysis was carried out to characterize the volatile compounds of the most potential strain, A. niger. The hexane soluble fraction showed the appearance of characteristic peaks of hexadecenoic acid methyl ester (4.41%), 10-octadecanoic acid methyl ester (3.79%), dodecane (3.21%), undecane (3.19%), gibepyrone A (0.15%), 3-methylundecane (0.36%), and citroflex A (0.38%). The ethyl acetate fraction of the bio-control fungi revealed the occurrence of major antifungal compounds, such as acetic acid ethyl ester (17.32%), benzopyron-4-ol (12.17%), 1,2,6-hexanetriol (7.16%), 2-propenoic acid ethanediyl ester (2.95%), 1-(3-ethyloxiranyl)-ethenone (0.98%), 6-acetyl-8-methoxy dimethyl chromene (0.96%), 4-hexyl-2,5-dihydro dioxo furan acetic acid (0.19%), and octadecanoic acid (1.11%). Furthermore, bio-control abilities could be due to hyper-parasitism, the production of secondary metabolites, and competition for sites and nutrients. Indeed, the results will enrich the existing knowledge of metabolomic information and support perspectives on the bio-control mechanism of A. niger.

The Role of Trichoderma in The Early Growth of Rice and Soybean in Saline Soils

“…Isolate Tc-31 exhibits the general characteristics of Trichoderma, including the ability to produce extracellular compounds such as acid phosphatase, cellulolytic enzymes, and encouraging microbial activity that aids plant growth [35], the ability to produce various plant growth regulators such as IAA and siderophore [36], and the ability to help plants cope with stress in the environment, including overcoming salinity [37]. One of the A. niger strains can manufacture secondary metabolites and compete for space and nutrients [40], in addition to creating antimetabolites against pathogenic fungus [41].…”

Fungal community structure and functional genes abundance in Brazilian drylands under desertification process

“…The order Hypocreales, one of the most abundant in native and restorative species, has high agronomic importance. The genus Trichoderma, one of the most studied for biological control (Gangaraj et al, 2023), is present in this order. On the other hand, the genus Fusarium, which includes many pathogenic species that cause a wide range of plant diseases that lead to major economic losses worldwide, also belongs to this order (Nikitin et al, 2023).…”