Transcriptomic insights into the synergistic effects of darkness and mechanical stimulation on peanut pod development

Peanuts are important oil crop with an atypical fruitification pattern. Darkness and mechanical stimulation are required to facilitate normal pod development. Despite some progress in understanding peanut pod development and its response to external environmental stimulation, numerous unresolved questions and knowledge gaps remain regarding the role of darkness and mechanical stimulation in this complex process.

In this study, we investigated the impacts of dark and mechanical stimulation on peanut pod development via transcriptome. A total of 55,087 genes, along with a series of DEGs and pathways, were identified among different treatment groups (CK, TB, TML, and TMB) that play crucial roles and offer a novel perspective on the role of photosynthesis during peanut pod development. Moreover, by utilizing weighted gene coexpression network analysis (WGCNA) we identified several hub genes (e.g., IAA9 (Ahy_B07g086610), BSK5 (Ahy_B03g068305), GRF7 (Ahy_B10g103808), and PER17 (Ahy_B10g105104)) and key pathways (e.g., plant hormonal and signal transduction pathway, and lignin biosynthesis pathway) that might be true candidates for peanut pod development. Further, the expression patterns of key candidates were validated via qRT-PCR during different pod development stages.

Overall, this study provides a comprehensive characterization of the mechanisms underlying peanut pod development in response to darkness and mechanical stimulation. These findings lay a foundation for exploring optimized growth conditions for peanut cultivation, while the identified key genes may serve as potential targets in future peanut breeding programs.