Infestation of Schizotetranychus oryzae (Acari: Tetranychidae) causes great losses in rice productivity. Infestation in Puitá INTA-CL cultivar reduced the number of seeds/plant, percentage of full seeds, 1,000 seeds weight, and seed length, whereas infestation in IRGA423 increased 1,000 seeds weight and seed length. Reduction in seed weight/plant caused by infestation was higher in Puitá INTA-CL than IRGA423. Thus, Puitá INTA-CL was established as susceptible, and IRGA423 as tolerant to S. oryzae infestation. Photosynthetic parameters were less affected by infestation in IRGA423 than in Puitá INTA-CL. Infestation also caused accumulation of H ₂ O ₂ , decreased cell membrane integrity and accelerated senescence in leaves of Puitá INTA-CL, while leaves of IRGA423 presented higher levels of phenolics compounds. Using proteomic analysis, we identified proteins related to plant defense, such as jasmonate synthesis, and related to other mechanisms of tolerance such as oxidative stress, photosynthesis, and DNA structure maintenance, more abundant in IRGA423 after seven days of infestation. We detected higher levels of silicon (as amorphous silica cells) in leaves of infested IRGA423 plants compared to Puitá INTA-CL, an element previously linked to plant defense. Our data shows that IRGA423 presents tolerance to S. oryzae infestation, and that multiple mechanisms might be employed by this cultivar. Highlight: This is the first report evaluating the defense responses (tolerance and susceptiblity) of two contrasting rice cultivars to Schizotetranychus oryzae mite infestation.

Brazilian microalgae represent an underexplored reservoir of bioactive compounds with promising biotechnological and dermocosmetic applications. In this study, eight native Brazilian microalgae strains were cultivated under control (C) and stress conditions, nitrogen depletion (N) and salt stress (S), to modulate their bioactive profiles. Derived acetone extracts (24 samples) were evaluated for their antioxidant and antibacterial activities relevant to skin health. The antioxidant capacity of extracts was assessed by three complementary methods: ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and superoxide anion radicals scavenging. Additionally, the antibacterial effects against four skin microorganisms (Staphylococcus epidermidis, Staphylococcus hominis, Staphylococcus aureus, and Cutibacterium acnes) were also assessed. Among the tested samples, extracts from Scenedesmus armatus (Extract 40C) and from Chlorella sorokiniana (Extract 198C) displayed the highest antioxidant potential, with DPPH radical reduction of 22.6 ± 1.6% and 20.7 ± 1.9% and FRAP values of 178.3 and 156.8 μmol FeSO₄/g extract, respectively. Superoxide scavenging assays showed IC₅₀ values of 150.9 μg/mL for sample 40C and 139.6 μg/mL for sample 198C. Regarding the antibacterial assay, the IC₅₀ values for S. epidermidis were notable, with sample 198C exhibiting the highest potency (10.3 µg/mL), closely matching the standard drug (12.4 µg/mL). The inhibitory capacity against C. acnes showed that samples 40C (58.4 µg/mL) and 198C (83.5 µg/mL) demonstrated antimicrobial relevance. Mechanistic assays suggested that the antibacterial effects of both samples may involve alterations in bacterial membrane integrity and DNA damage. Overall, these findings highlight the dermocosmetic potential of native Brazilian microalgae, still largely untapped in biotechnology, as natural sources of multifunctional ingredients for the development of sustainable skin care formulations.

Cultivated rice ( Oryza sativa L.) is frequently exposed to multiple stresses, including Schizotetranychus oryzae mite infestation. Rice domestication has narrowed the genetic diversity of the species, reducing the stress resistance and leading to a wide susceptibility. Therefore, wild rice species present an alternative to search for this lost variability. Aiming to observe the response of two wild rice species ( Oryza barthii and Oryza glaberrima ) and two Oryza sativa genotypes (cv. Nipponbare and O. sativa f. spontanea ) to S. oryzae infestation, we used agronomic, physiological and molecular analyses. Surprisingly, analyses of leaf damage, histochemistry, chlorophyll concentration and chlorophyll fluorescence showed that the wild species present higher level of leaf damage, increased accumulation of H ₂ O ₂ and lower photosynthetic capacity when compared to O. sativa genotypes under infested conditions. Infestation did not affect plant height, but decreased tiller number, except in cv. Nipponbare, whose development was not affected. Infestation also caused the death of wild plants during the reproductive stage, unlike O. sativa genotypes, which were able to tolerate stress and produce seeds. While infestation did not affect the weight of 1,000 grains in both O. sativa genotypes, the number of panicles per plant was affected only in O. sativa f. spontanea , and the percentage of full seeds per panicle and seed length were increased only in cv. Nipponbare. Proteomic analysis allowed us to identify 195 differentially abundant proteins when comparing susceptible ( O. barthii ) and tolerant ( O. sativa cv. Nipponbare) genotypes under control and infested conditions. We found that O. barthii has a less abundant antioxidant arsenal. In addition, it is unable to modulate proteins involved with general metabolism and energy production under infested condition. In Nipponbare we found high abundance of detoxification-related proteins, general metabolic processes and energy production, which allows us to suggest that, under infested condition, the primary metabolism is maintained more active compared to O. barthii . Also, Nipponbare presents a greater abundance of defense-related proteins, such as osmotin, ricin B-like lectin, and protease inhibitors of the Bowman Birk trypsin inhibitor family, as well as higher levels of the compatible osmolyte Proline under infested condition. Identification of these differentially abundant proteins can be used as an important biotechnological tool in breeding programs that aim increased tolerance to phytophagous mite infestation.