Abstract
Wheat can adapt to most agricultural conditions across temperate regions. This success is the result of phenotypic plasticity conferred by a large and complex genome composed of three homoeologous genomes (A, B, and D). Although drought is a major cause of yield and quality loss in wheat, the adaptive mechanisms and gene networks underlying drought responses in the field remain largely unknown. Here, we addressed this by utilizing an interdisciplinary approach involving field water status phenotyping, sampling, and gene expression analyses. Overall, changes at the transcriptional level were reflected in plant spectral traits amenable to field-level physiological measurements, although changes in photosynthesis-related pathways were found likely to be under more complex post-transcriptional control. Examining homoeologous genes with a 1:1:1 relationship across the A, B, and D genomes (triads), we revealed a complex genomic architecture for drought responses under field conditions, involving gene homoeolog specialization, multiple gene clusters, gene families, miRNAs, and transcription factors coordinating these responses. Our results provide a new focus for genomics-assisted breeding of drought-tolerant wheat cultivars.
Highlights
Results and discussionMaintaining plant growth and yield under drought stress is a major objective for wheat breeding programs worldwide
Transcriptomics is a powerful approach to identify gene regulatory networks, transcription factors, and miRNAs involved in the stress response and to identify differentially expressed genes during drought treatments
Changes at the transcriptional level were observed only for a single component of photosystem II, PsbQ, which was overexpressed in response to drought (Table S4). These results suggest that drought-induced changes in pathways related to photosynthesis are likely under more complex posttranscriptional control than those described above (Fankhauser and Aubry 2017)
Summary
Maintaining plant growth and yield under drought stress is a major objective for wheat breeding programs worldwide. As part of defining the genome architecture of field drought response, we identified a ~ 50-Mb genomic region on the long arm of group 5 chromosomes containing several drought-responsive DE genes (Fig. 6) and genes previously associated with drought tolerance (Quarrie et al 1994) This region included genes known to affect drought tolerance (Close 1996; Iuchi et al 2001) including those from the carotenoid pathway (PSY3, NCED) and the DHN chromosome 5 cluster, as well as a gene encoding UDP glucose-6dehydrogenase (Table S5), which partitions carbon resources during spike development to ensure fertility and grain yield (Ferreira and Sonnewald 2012). This work, alongside the new genomic resources in wheat, provides a focus for breeding of drought-tolerant wheat cultivars by exploiting the genome architecture of gene clusters and the opportunity to adjust the interactions within gene networks through genomics-informed breeding
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
