Maize (Zea mays) produces terpenoid-based chemical defenses through a large family of terpene synthases, but the contributions of individual enzymes to specific compounds and stress resistance remain difficult to predict. Maize terpene synthase 8 (ZmTPS8) produces multiple sesquiterpenes in heterologous systems, but its in planta function remains unknown. We integrated a metabolite genome-wide association study (mGWAS), CRISPR/Cas9 generated tps8 loss-of-function mutants, metabolite profiling, and biotic stress assays to define ZmTPS8's role in terpene synthesis and biotic stress responses. The mGWAS identified ZmTPS8 as the primary locus associated with herbivore-induced emission of the sesquiterpene volatile germacrene D. Consistently, ZmTPS8 expression was induced by foliar and root herbivory, and tps8 mutants exhibited reduced emission of germacrene D, α-copaene, and δ-cadinene during Spodoptera frugiperda feeding. Loss of ZmTPS8 increased S. frugiperda larval growth but did not affect the belowground herbivore Diabrotica virgifera virgifera. ZmTPS8 also contributed to resistance against sugarcane mosaic virus, and the fungal pathogen Fusarium verticillioides, affecting terpenoid profiles, global metabolism, and fungal toxin production, but had no impact on Cochliobolus heterostrophus or Pythium spp. susceptibility. Together, these results demonstrate that ZmTPS8 contributes to maize defense in a threat-dependent manner, shaping volatile emissions and defense outcomes.
Ariel Sorg, Hui Liu, Ho-Ang V. Tang et al.· Journal of Experimental Bota...· 0 citations
Abstract Genomic selection (GS) is a powerful tool for accelerating genetic gain in potato (Solanum tuberosum L.) breeding, particularly for complex traits. In this study, three practical aspects of GS implementation in a potato breeding program were examined. First, the predictive ability of GS models was evaluated for three key traits (total yield, marketable yield, and specific gravity) using two elite potato populations with shared ancestry, tested across seven location‐year environments. Two cross‐validation strategies were used to reflect practical breeding scenarios: predicting unphenotyped lines in known environments and predicting clonal performance in unknown environments. Four models were evaluated, two of which included genotype‐by‐environment interactions. Tuber specific gravity showed higher and more consistent prediction accuracy across environments, supporting the evidence that it is a more stable trait. Second, the impact of genotyping platforms and marker density on GS performance were examined, as the two populations were genotyped using two different targeted sequencing platforms: Flex‐seq (22K loci) and DArTag (4K loci), sharing ∼4K common loci, that allowed direct comparison. Prediction accuracies were comparable across platforms, indicating that both are suitable for GS implementation, with the choice depending on breeding goals, cost, and throughput considerations. Finally, the long‐term impact of GS on genetic gain was assessed through stochastic simulation of a 30‐year breeding pipeline, comparing conventional phenotypic selection with GS‐assisted selection scenarios. GS scenarios achieved higher long‐term genetic gains, though practical deployment should consider both cost and breeding objectives. Our findings for the three aspects of this study support the integration of GS into potato breeding programs, while highlighting key considerations for its effective implementation.
R. Dhakal, M. A. Peixoto, Leo Hoffmann et al.· The Plant Genome· 0 citations
This study provides chemical and genetic insights into the evolution of tomato flavor during domestication and subsequent improvement, identifying the complexity of genetic control of fruit flavor chemicals as well as a number of new alleles that can be used to improve the contents of flavor-linked chemicals.
Xiang Li, Denise M. Tieman, Yue Huang et al.· Proceedings of the National...· 0 citations
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