ABSTRACT
Boron (B) is an important micronutrient required for the normal growth and development of plants. However, its excess in the soil causes severe damage to plant tissues, which affects the final yield. Wheat, one of the main staple crops, has been reported to be largely affected by B toxicity stress in arid and semi-arid regions of the world. The prevalence of B toxicity stress can be addressed by utilizing wild wheat genotypes with a variant level of stress tolerance. Wild wheat relatives have been identified as a prominent source of several abiotic stress-tolerant genes. However, Aegilops species in the tertiary gene pool of wheat have not been well exploited as a source of B toxicity tolerance. This study explores the root and shoot growth, proline induction, and extent of lipid peroxidation in 19 Aegilops accessions comprising 6 different species and the B-tolerant check wheat cultivar Bolal 2973 grown under Control (3.1 µM B), toxic (1 mM B), and highly toxic (10 mM B) B stress treatment. B toxicity stress had a more decisive impact on growth parameters as compared to the malondialdehyde (MDA) and proline content. The obtained results suggested that even the genotypes with high shoot B (SB) accumulation can be tolerant to B toxicity stress, and the mechanism of B redistribution in leaves should be studied in detail. It has been proposed that the studied Aegilops accessions can be potentially used for genetically improving the B toxicity-tolerance trait due to a high level of variation in the response toward high B toxicity. Though a number of accessions showed suppression in the root and shoot growth, very few accessions with stress adaptive plasticity to B toxicity stress leading to an improvement of shoot growth parameters could be determined. The two accessions, Aegilops biuncialis accession TGB 026219 and Aegilops columnaris accession TGB 000107, were identified as the potential genotypes with B toxicity stress tolerance and can be utilized for developing a pre-breeding material in B tolerance-based breeding programs.
ABSTRACT
Fusarium head blight (FHB) disease that occurs in wheat is caused by Fusarium graminearum and is a major risk to wheat yield. Although several research efforts focusing on FHB have been conducted in the past several decades, conditions have become more critical due to the increase in its virulent forms. In such a scenario, conferring complete resistance in plants seems to be difficult for handling this issue. The phenotyping for FHB and finding a solution for it at the genetic level comprises a long-term process as FHB infection is largely affected by environmental conditions. Modern molecular strategies have played a crucial role in revealing the host-pathogen interaction in FHB. The integration of molecular biology-based methods such as genome-wide association studies and marker-based genomic selection has provided potential cultivars for breeding programs. In this review, we aim at outlining the contemporary status of the studies conducted on FHB in wheat. The influence of FHB in wheat on animals and human health is also discussed. In addition, a summary of the advancement in the molecular technologies for identifying and developing the FHB-resistant wheat genetic resources is provided. It also suggests the future measures that are required to reduce the world's vulnerability to FHB which was one of the main goals of the US Wheat and Barley Scab Initiative.
