Molecular Soil Biology 2025, Vol.16, No.5, 241-254 http://bioscipublisher.com/index.php/msb 245 Figure 1 A graphical abstract of bacterial interactions and plant protection/health within the rhizosphere. (a) The plant releases root exudates (yellow stars) into the soil to either manipulate rhizosphere microbial community dynamics or recruit (double-ended arrow) beneficial bacteria (pink cells) after recognizing pathogen invasion. The recruited bacteria could suppress (blunt arrow) pathogenic bacteria (dark green) or ISR enhancing plant immunity as well as nutrient acquisition (green arrow). Successful pathogenic bacteria secrete effector proteins (red circles) to manipulate host immunity (red arrow) for their advantage (red arrow) and modulating microbiome compositions (dotted arrow). (b) Within the rhizosphere, where resources are deficient, bacteria cooperate to share public goods among kins (green cells). However, cheating can also occur (red cell). (c) The T6SS enables bacteria to outcompete other microbes (some of which maybe pathogenic) by killing or inhibiting their growth of target cells. Alternatively, bacteria produce antibiotics and/or bacteriocins to either kill or inhibit competing microbes (Adopted from Chepsergon and Moleleki, 2023) 6.2 Root responses to flooding and poor aeration Waterlogging or poor ventilation can cause roots to lack oxygen, impede breathing, and even lead to tissue necrosis. Flood-tolerant corn varieties can rapidly induce the formation of aerenchyma in the root cortex, thereby enhancing their adaptability in low-oxygen environments. Under waterlogging conditions, the related genes of corn (such as alanine aminotransferase, alcohol dehydrogenase, etc.) are up-regulated, which helps the root maintain energy metabolism and signal transduction, thereby enhancing survival (Kaur et al., 2021). The microbial community in the rhizosphere also changes dynamically with water conditions. Some specific bacteria (such as strains that can produce 1-aminocyclopropane-1-carboxylic acid deaminase) can alleviate waterlogging damage to the roots (Gao et al., 2023). 6.3 Climate change scenarios affecting root–soil interactions In recent years, climate change has brought about more extreme weather. Drought, heat waves and abnormal precipitation can all have a considerable impact on the root-soil interaction of corn. When high temperatures and drought occur simultaneously, root growth is restricted, the root/stem ratio increases, and the microbial structure in the rhizosphere also undergoes reorganization. One example is that if the number of actinomycetes increases, then the number of Pseudomonas will decrease, having a negative impact on nutrient cycling and stress resistance (Keya et al., 2024; Swift et al., 2024; Yuan et al., 2024). In this case, corn regulates stomatal density, alters root structure, and increases signal secretions to adapt to water and heat stress (Serna, 2022; Kim and Lee, 2023). Subsequent related studies can utilize multi-omics and molecular breeding methods to screen out corn varieties with optimized root structure and stronger drought and flood resistance (Sheoran et al., 2022; Li et al., 2023; Peer et al., 2024). 7 Agricultural Management Strategies 7.1 Breeding maize for improved root traits Root structure, root length density and root surface area are several main pursuit goals in modern corn breeding research. Through QTL mapping and genomic selection, scientists can screen out traits that efficiently absorb water and nutrients from corn (such as deeper roots, larger root biomass, more reasonable root structure, etc.)
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