Enhancing aluminium resistance in wheat ( <i>Triticum aestivum</i> L.) by exploring for novel genes in the wheat genome

Abstract Aluminium (Al 3+ ) toxicity is a major constraint to crop production worldwide and is considered second only to drought for its importance as an agronomic challenge. A common practice to manage the impact is the application of lime but this is expensive, and it can take years for the lime to be effective in ameliorating the subsoil acidity. Plant species with a natural ability to adapt to Al 3+ toxicity offer an option to maintain production while amelioration efforts continue, especially in low-rainfall areas where yield responses to lime is less profitable. In wheat ( Triticum aestivum L.), the genes conferring Al 3+ resistance have been extensively researched over the years through classical inheritance, cytogenetic, quantitative trait locus (QTL) and genome-wide association studies, and transcriptional analyses. As a focal point for this discussion, we assembled a total of 212 QTL from research papers published between 2006 and 2024, and their physical positions were projected on the sequenced genome of the moderately Al 3+ -resistant hexaploid wheat variety, Chinese Spring. The markers were distributed across the 21 wheat chromosomes, with the highest numbers on chromosomes 3B, 4D and 7A and the lowest on chromosomes 3D and 5D. The physical mapping of significantly associated markers onto the reference genome map uncovered novel candidate genes. These include wheat aluminium-induced (Wali) genes, the ATP-binding cassette (ABC) transporters, phytosulfokine receptor (PSKR), PIN-formed (PIN, auxin transporter), NAC (NAC domain), WRKY (WRKY domain) and natural resistance-associated macrophage proteins (NRAMP). These were discussed to provide a contextual review of gaps that can be exploited in enhancing Al 3+ resistance in wheat, which can lead to the discovery of novel genes and the development of improved cultivars.