Biology subjects

Ricachenevsky, F. K.

Publications and source records attributed to Ricachenevsky, F. K..

8 recordsLinked to original sources

bioRxiv2026

Asynchronous origins of Yellow-Stripe transporters and Nicotianamine Synthase underlie the evolution of plant Strategy-II iron uptake

Plants acquire iron using two canonical mechanisms: reduction-based uptake (Strategy I) and chelation-based uptake (Strategy II). Although Strategy II is characteristic of grasses, genes associated with chelated-metal transport occur broadly across plant lineages, obscuring how this pathway evolved. Here, we reconstruct the evolutionary history of Yellow Stripe-Like (YSL) transporters and Nicotianamine Synthase (NAS) across Archaeplastida and their closest non-plant homologs. Phylogenomic, distributional, and structural analyses reveal pronounced temporal uncoupling between these gene families. YSL most likely originated early in Viridiplantae and represents the deepest evolutionary module of the chelated-metal transport system. In contrast, NAS appeared much later through independent horizontal gene transfer events from fungi into euphyllophytes and specific moss lineages. This timing indicates that YSL-mediated transport initially functioned independently of nicotianamine, implying ancestral use of alternative siderophores. A pronounced expansion of YSL genes in Poaceae coincides with the emergence of canonical Strategy II, suggesting that this pathway arose by exaptation of pre-existing chelated-metal transport mechanisms.

plant biology↗

bioRxiv2025

Double knockout of rice OsVIT1 and OsVIT2 genes reveals a trade-off between iron biofortification and iron excess tolerance

Rice (Oryza sativa L.) is a staple food for half of the worlds population, but lacks essential nutrients such as iron (Fe). Fe deficiency is one of the most common nutritional problems in humans, and biofortification of rice grains is a cost-effective approach to deliver more Fe to peoples diet. Two Vacuolar Iron Transporters, OsVIT1 and OsVIT2, were shown to negatively regulate Fe translocation to rice developing panicles, as single mutants osvit1 and osvit2 have increased Fe concentration in seeds. Importantly, rice plants are frequently cultivated in waterlogged soils that are highly reductive and prone to Fe3+ reduction to the more soluble Fe2+, which can accumulate and cause Fe toxicity. Little is known about which genes control Fe excess detoxification. OsVIT1 and OsVIT2 transport Fe into the vacuole, and OsVIT2 is induced under Fe excess, but whether they play a role in Fe detoxification was not demonstrated. We generated double mutants osvit1osvit2 using CRISPR-Cas9 to test whether loss of function of both genes could increase Fe concentration in seeds, and to test whether their loss of function has impact in rice Fe excess tolerance. We showed that osvit1osvit2 double mutants accumulated more Fe in brown rice. Fe accumulation was clear in embryo scutellum and plumule, suggesting VIT transporters have a role in determining Fe spatial distribution. We also showed that root uptake contributed significantly for increased Fe accumulation in osvit1osvit2 seeds, suggesting OsVIT1 and OsVIT2 are involved in sequestering Fe in vegetative tissues and decreasing translocation. Strikingly, we found that osvit1osvit2 plants were more sensitive to Fe excess, revealing a trade-off between Fe biofortification and Fe excess tolerance. Our data indicates OsVIT1 and OsVIT2 are key for Fe excess detoxification, which should be considered in their use as targets for biofortification.

plant biology↗

bioRxiv2022

Ferrous iron uptake via IRT1/ZIP evolved at least twice in green plants

Iron (Fe) is an essential micronutrient for virtually all living beings, being practically irreplaceable because of its unique electrochemical properties that enable or facilitate a series of biochemical processes, including photosynthesis. Although Fe is abundant on Earth, it is generally found in the poorly soluble form Fe3+. Most extant plants have established Fe absorption strategies that involve Fe uptake in the soluble form Fe2+. The model angiosperm Arabidopsis thaliana, for example, captures Fe through a mechanism that lowers the pH through proton pumping to the rhizosphere to increase Fe3+ solubility, which is then reduced by a plasma membrane-bound reductase and transported into the cell by the ZIP family protein IRT1. ZIP proteins are transmembrane transporters of a variety of divalent metals such as Fe2+, Zn2+, Mn2+ and Cd2+. In this work, we investigate the evolution of functional homologs of IRT1/ZIP in the supergroup of photosynthetic eukaryotes Archaeplastida (Viridiplantae + Rhodophyta + Glaucophyta) using a dataset of 41 high-quality genomes of diverse lineages. Our analyses suggest that Fe is acquired through deeply divergent ZIP proteins in land plants and chlorophyte green algae, indicating that Fe2+ uptake by ZIP family proteins evolved at least twice independently during green plant evolution. Sequence and structural analyses indicate that the archetypical IRT proteins from angiosperms likely emerged in streptophyte algae before the origin of land plants and might be an important player in green plant terrestrialization, a process that involved the evolution of Fe acquisition in terrestrial subaerial settings.

genomics↗

bioRxiv2020

Arabidopsis thaliana zinc accumulation in leaf trichomes is correlated with zinc concentration in leaves

Zinc (Zn) is a key micronutrient. In humans, Zn deficiency is a common nutritional disorder, and most people acquire dietary Zn from eating plants. In plants, Zn deficiency can decrease plant growth and yield. Understanding Zn homeostasis in plants can improve agriculture and human health. While root Zn transporters in plat model species have been characterized in detail, comparatively little is known about shoot processes controlling Zn concentrations and spatial distribution. Previous work showed that Zn hyperaccumulator species such as Arabidopsis halleri accumulate Zn and other metals in leaf trichomes. The model species Arabidopsis thaliana is a non-accumulating plant, and to date there is no systematic study regarding Zn accumulation in A. thaliana trichomes. Here, we used Synchrotron X-Ray Fluorescence mapping to show that Zn accumulates at the base of trichomes of A. thaliana, as had seen previously for hyperaccumulators. Using transgenic and natural accessions of A. thaliana that vary in bulk leaf Zn concentration, we demonstrated that higher leaf Zn increases total Zn found at the base of trichome cells. Furthermore, our data suggests that Zn accumulates in the trichome apoplast, likely associated with the cell wall. Our data indicates that Zn accumulation in trichomes is a function of the Zn status of the plant, and provides the basis for future studies on a genetically tractable plant species aiming at understanding the molecular steps involved in Zn spatial distribution in leaves.

plant biology↗

bioRxiv2020

Gender, race and parenthood impact academic productivity during the COVID-19 pandemic: from survey to action.

While the Coronavirus disease 2019 (COVID-19) pandemic is altering academia dynamics, those juggling remote work and domestic demands - including childcare - have already felt the impacts on productivity. Female authors are facing a decrease in papers submission rates since the beginning of the pandemic period. The reasons for this decline in women productivity need to be further investigated. Here we show the influence of gender, parenthood and race in academics productivity during the pandemic period, based on a survey answered by 3,345 Brazilian academics from various knowledge areas and research institutions. Findings revealed that male academics - especially childless ones - were the least affected group, whereas female academics, especially Black women and mothers, were the most impacted group. This scenario will leave long-term effects on the career progression of the most affected groups. The results presented here are crucial for the development of actions and policies that aim to avoid further deepening the gender gap in science. This particular situation we are facing during the pandemic demands institutional flexibility and academia should foster the discussion about actions to benefit Black scientists and academics with families in the post-pandemic scenario.

scientific communication and education↗

bioRxiv2020

Cold tolerance in rice plants is partially controlled by root responses

Rice (Oryza sativa L.) ssp. indica is the most cultivated species in the South of Brazil. However, these plants face low temperature stress from September to November, which is the period of early sowing, affecting plant development during the initial stages of growth, and reducing rice productivity. This study aimed to characterize the root response to low temperature stress during the early vegetative stage of two rice genotypes contrasting in their cold tolerance (CT, cold-tolerant; and CS, cold-sensitive). Root dry weight and length, as well as number of root hairs, were higher in CT than CS when exposed to cold treatment. Histochemical analyses indicated that roots of CS genotype present higher levels of lipid peroxidation and H2O2 accumulation, along with lower levels of plasma membrane integrity than CT under low temperature stress. RNAseq analyses revealed that the contrasting genotypes present completely different molecular responses to cold stress. The number of over-represented functional categories was lower in CT than CS under cold condition, suggesting that CS genotype is more impacted by low temperature stress than CT. Several genes might contribute to rice cold tolerance, including the ones related with cell wall remodeling, cytoskeleton and growth, signaling, antioxidant system, lipid metabolism, and stress response. On the other hand, high expression of the genes SRC2 (defense), root architecture associated 1 (growth), ACC oxidase, ethylene-responsive transcription factor, and cytokinin-O-glucosyltransferase 2 (hormone-related) seems to be related with cold sensibility. Since these two genotypes have a similar genetic background (sister lines), the differentially expressed genes found here can be considered candidate genes for cold tolerance and could be used in future biotechnological approaches aiming to increase rice tolerance to low temperature.

plant biology↗

bioRxiv2020

Nipponbare and wild rice species as unexpected tolerance and susceptibility sources against Schizotetranychus oryzae (Acari: Tetranychidae) mite infestation

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 H2O2 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.

plant biology↗

bioRxiv2019

The Mitochondrial Iron Regulated (MIR) gene is Oryza genus-specific and evolved before the speciation of major AA-genome lineages

Rice (Oryza sativa L.) is both a model species and an economically relevant crop. The Oryza genus comprises 25 species, which constitute a genetic reservoir for cultivated rice breeding. Genomic data is available for several Oryza species, making it a good model for genetics and evolution within closely related species. The Mitochondrial Iron Regulated (MIR) gene was previously implicated in O. sativa Fe deficiency response, and was considered an orphan gene present only in rice. Here we show that MIR is also found in other Oryza species that belong to the AA genome group. We characterized the evolutionary pattern of MIR genes within the Oryza genus. Our data suggest that MIR originated de novo from non-coding sequences present only in AA genome species, but these sequences in turn are derived from an exon fragment of Raffinose Synthase genes, present in several groups of monocots. We also show that all species that have a putative functional MIR conserve their regulation by Fe deficiency, with the exception of Oryza barthii. In O. barthii, the MIR coding sequence was translocated to a different chromosomal position and separated from its regulatory region, which led to a lack of Fe deficiency responsiveness. Moreover, we show that MIR co-expression subnetwork cluster in O. sativa is responsive to Fe deficiency, evidencing the importance of the newly originated gene in Fe uptake. This work establishes that MIR is not an orphan gene as previously proposed, but a de novo originated gene within the Oryza genus. We also showed that MIR is undergoing genomic changes in at least one species (O. barthii), which can impact its role in Fe deficiency.

plant biology↗