Sex segregation increases the cost of Carica papaya production through seed-based propagation. Therefore, in vitro techniques are an attractive option for clonal propagation, especially of hermaphroditic plants. Here, we performed a temporal analysis of the proteome of C. papaya calli aiming to identify the key players involved in embryogenic callus formation. Mature zygotic embryos used as explants were treated with 20 μM 2,4-dichlorophenoxyacetic acid to induce embryogenic callus. Total proteins were extracted from explants at 0 (zygotic embryo) and after 7, 14, and 21 days of induction. A total of 1407 proteins were identified using a bottom-up proteomic approach. The clustering analysis revealed four distinct patterns of protein accumulation throughout callus induction. Proteins related to seed maturation and storage are abundant in the explant before induction, decreasing as callus formation progresses. Carbohydrate and amino acid metabolisms, aerobic respiration, and protein catabolic processes were enriched throughout days of callus induction. Protein kinases associated with auxin responses, such as SKP1-like proteins 1B, accumulated in response to callus induction. Additionally, regulatory proteins, including histone deacetylase (HD2C) and argonaute 1 (AGO1), were more abundant at 7 days, suggesting their role in the acquisition of embryogenic competence. Predicted protein–protein networks revealed the regulatory role of proteins 14-3-3 accumulated during callus induction and the association of proteins involved in oxidative phosphorylation and hormone response. Our findings emphasize the modulation of the proteome during embryogenic callus initiation and identify regulatory proteins that might be involved in the activation of this process.

Southern leaf blight (SLB), caused by Bipolaris maydis, poses a significant threat to maize and popcorn production. To understand the molecular mechanisms underlying SLB resistance, we conducted a high-throughput proteomic analysis comparing SLB-resistant (L66) and SLB-susceptible (L51) popcorn genotypes at four and ten days after inoculation (DAI). A total of 717 proteins were identified, with 151 differentially accumulated proteins (DAPs) between the genotypes. Eighteen DAPs exhibited the same regulatory pattern in both the SLB-resistant and SLB-susceptible genotypes at four (R4/S4) and ten (R10/S10) DAI. The protein-protein interaction (PPI) network of differentially accumulated proteins (DAPs) linked to SLB resistance and susceptibility enriched specific metabolic pathways in the SLB response, including photosynthesis, ribosome, ascorbate and aldarate metabolism, glutathione metabolism, and carbon metabolism. Proteins such as photosystem II 11 kD protein (B4FRJ4, PSB27-1), which was up-regulated at both time points (R4/S4 and R10/S10), and 60S acidic ribosomal protein P0 (A0A1D6LEZ7, RPP0B), which was unique to the resistant genotype at both time points (R4 and R10), highlighted the importance of maintaining photosynthetic efficiency and protein synthesis during pathogen attack. Additionally, dehydroascorbate reductase like-3 (B4F817, DHAR3) was consistently up-regulated at both time points in resistant genotypes, emphasizing its role in redox balance and ROS detoxification. In contrast, glyceraldehyde-3-phosphate dehydrogenase (K7UGF5, GAPC2), a glycolytic enzyme, was unique to the susceptible genotype, suggesting its involvement in managing energy metabolism under stress conditions. Our findings suggest that resistance to SLB in popcorn involves a combination of enhanced photosynthetic repair, redox homeostasis, and ribosomal protein activity, providing new potential molecular targets, such as DHAR3 and RPP0B, for genetic improvement in SLB resistance. These results offer valuable insights into breeding programs aimed at developing SLB-resistant popcorn varieties.

Plants exhibit phenotypic plasticity in response to environmental variations, which can lead to stable genetic and physiological adaptations if exposure to specific conditions is prolonged. Myrsine coriacea demonstrates this through its ability to thrive in diverse environments. The objective of the article is to investigate the adaptive responses of M. coriacea by cultivating plants from seeds collected at four different altitudes in a common garden experiment. Through integrated physiological and proteomic analyses, we identified 170 differentially accumulated proteins and observed significant physiological differences among the populations. The high-altitude population (POP1) exhibited a unique proteomic profile with significant down-regulation of proteins involved in carbon fixation and energy metabolism, suggesting a potential reduction in photosynthetic efficiency. Physiological analyses showed lower leaf nitrogen content, net CO ₂ assimilation rate, specific leaf area, and relative growth rate in stem height for POP1, alongside higher leaf carbon isotopic composition ( δ13C ) and leaf carbon ( C ) content. These findings provide insight into the complex interplay between proteomic and physiological adaptations in M. coriace a and underscore the importance of local adaptations. This study enhances our understanding of how altitude-specific selection pressures can shape plant molecular biology and physiology, offering valuable perspectives for predicting plant responses to global environmental changes. Highlight: This study unveils proteomic and physiological adaptations in a high-altitude M. coriacea population with reduced carbon fixation and energy metabolism.

A embriogênese somática em cana-de-açúcar possibilita propagação de mudas em larga-escala e a regeneração de plantas geneticamente modificadas, representando uma ferramenta biotecnológica fundamental