Variations in the Functional Diversity of Rhizosphere Microbiome of Healthy and Northern Corn Leaf Blight Infected Maize (Zea mays L.)

Abstract

Metagenomics is a scientific breakthrough that can reveal the variations in the microbial diversities and functions between the healthy and diseased plants, towards a productive deployment in diverse biotechnological processes and agricultural activities. This study investigated the possible functional diversity in the rhizosphere microbiome of both healthy and Northern Corn Leaf Blight (NCLB) infected maize growing at farms in the Lichtenburg (LI) and Mafikeng (MA) areas of the North West Province, South Africa. We hypothesized variations in the abundance and diversities of microbial functions in the healthy (LI and MA) and diseased (LID and MAD) maize plants. Hence, we extracted DNA from the healthy and diseased maize rhizosphere in the two maize farms and sequenced using a shotgun approach. Using the SEED subsystem, we discovered that the healthy rhizosphere maize plant was dominated by 24 functional categories, while the NCLB infected rhizosphere maize plant was dominated by 4 functional categories. Alpha diversity analysis showed no significant (p > 0.05) difference between the healthy and diseased maize rhizosphere. However, the analysis of beta diversity showed a significant difference. The substantial abundance of functional groups detected especially in LI indicates that presence of plant diseases altered the functions of soil microbiomes. The significant abundance of the unknown role of rhizosphere microbiomes in disease management suggests the presence of some undiscovered functional genes associated with the microbiome of the healthy maize rhizosphere. Hence, further investigation is needed to explore the roles of these functional genes for their agricultural or biotechnological relevance.

Characterization and biocontrol potential of some rhizobacteria against fungal pathogens causing foliar diseases in maize

“…This result is consistent with the earlier characteristics of each of the isolates discussed. Thus, the presence of bacteria with biocontrol potentials in the rhizosphere soil of maize plants examined in this study signifies the natural potential of plant root architecture and exudation to modulate the rhizosphere microbiome, as to function based on the plant's requirement (Dlamini et al, 2023a;Marco et al, 2022).…”

“…It is an essential crop that plays a strategic role in actualizing the second United Nations Sustainable Development Goal (SDG 2) of attaining zero hunger (Akanmu et al, 2023a;Ngoune Tandzi & Mutengwa, 2019). This is a result of the nutritional benefits derived from maize by millions of people across the world who depend on it as a staple food (Dlamini et al, 2023a). In addition, the relatively high yield potential of maize and the ability to grow in diverse kind of environments ensures its stability in food supply both to human and the livestock (Poole et al, 2021).…”

“…Despite its resilience, the growth and yield of maize are adversely affected by pests and diseases caused by fungi, viruses, nematodes and bacteria (Akanmu et al, 2023b;Dlamini et al, 2023b;Gadag et al, 2021). The infection of pathogenic organisms has been found to often result in significant yield losses (Akanmu et al, 2020;Dlamini et al, 2023b;Imade & Babalola, 2021), and fungi constitute an important domain of microorganisms infecting the cultivated maize (Babalola et al, 2022).…”

“…Despite its resilience, the growth and yield of maize are adversely affected by pests and diseases caused by fungi, viruses, nematodes and bacteria (Akanmu et al, 2023b;Dlamini et al, 2023b;Gadag et al, 2021). The infection of pathogenic organisms has been found to often result in significant yield losses (Akanmu et al, 2020;Dlamini et al, 2023b;Imade & Babalola, 2021), and fungi constitute an important domain of microorganisms infecting the cultivated maize (Babalola et al, 2022). Fungi causing the foliar diseases of maize have been reported across the world including grey leaf spot caused by Cercospora spp., common rust (Puccinia sorghi), leaf spot disease (Phoma herbarum), brown spot (Physoderma maydis), Phaeosphaeria leaf spot (Phaeosphaeria maydis), downy mildew (Peronosclerospora sorghi), Bipolaris zeicola (Helminthosporium leaf spot) and a range of foliar and root diseases caused by Fusarium verticillioides (Babalola et al, 2022;Belisário et al, 2022;Korsman et al, 2012;Liu et al, 2021).…”