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Herbivorous insects and pathogens cause severe damage to rice tissues, affecting yield and grain quality. Damaged cells trigger downstream defense responses through various signals. Extracellular ATP (eATP), a signaling molecule released during mechanical cell damage, is considered a constitutive damage-associated molecular pattern (DAMP), which is crucial for initiating plant defense responses. Thus, understanding how rice plants cope with DAMPs such as eATP is essential. Here, we found that exogenous ATP affected rice growth and development, cell wall composition, chloroplast development, and cell death. Subsequent global transcriptome analysis revealed that several pathways were involved in the eATP response, including genes related to cell surface receptors, cell wall organization, chlorophyll biosynthesis, heat and temperature stimulation, epigenetic regulation, and reactive oxygen species metabolism. Cell surface receptors, including members of the lectin receptor-like kinases (LecRKs), were found to participate in the eATP response. We further investigated ATP-induced genes in T-DNA activation mutants of OsLecRKs, demonstrating their involvement in eATP signaling in rice. This study confirms a DAMP-mediated transcriptional response in plants and provides novel candidates for advancing resistant rice breeding against insect herbivores and pathogens. 

Abstract Bangkok, Thailand is a tropical Asian megacity with high aerosol concentrations and frequent thunderstorm activity. This investigation examines the covariation between thermodynamics, aerosols, and thunderstorms, using lightning stroke counts as a measure of intensity, for a five-year period (2016–2020). The investigation incorporates data from the aerosol robotic network (AERONET), ERA-5 reanalysis, ground-based air quality stations, and total lighting data from Vaisala Inc.’s GLD360 network to examine the aerosol-thermodynamic interrelationships within thunderstorm initiation environments. Results indicate that aerosol impacts on thunderstorms are robust and, when examined in concert with instability, can augment lightning. Thermodynamic instability is also positively correlated with stroke counts in thunderstorms. Particulate matter greater than 10 µg m^-3(PM10) concentration is significantly higher in thunderstorms containing more than 100 strokes, supporting the potential role of aerosols in promoting the non-inductive charge process. The emergence of a “boomerang” or threshold effect is also evident as aerosol optical depth (AOD) increases. Evidence suggests increasing AOD initially promotes, then limits, instability and thunderstorm intensity. Finally, there exists a positive relationship between aerosol concentration and particle size in thunderstorm initiation environments. 

Numerous temperature and environmental proxies are based on glycerol dialkyl glycerol tetraethers (GDGTs), which are membrane lipids commonly found in the water columns and sediments of lakes. The TEX86 temperature proxy is based on isoprenoid GDGTs, which are produced by members of the archaea, and is used to reconstruct lake surface temperature. Branched GDGTs are lipids produced by bacteria and form the basis of the MBT′5ME temperature proxy. Although many outstanding questions still exist regarding proxies based on isoprenoid and branched GDGTs, both compound classes have been relatively well-studied in lakes. More recently, other types of GDGTs and related compounds are increasingly being reported from lacustrine sediments including hydroxylated GDGTs (OH-GDGTs) and glycerol monoalkyl glycerol tetraethers (GMGTs). In the process of generating lacustrine TEX86 or MBT′5ME temperature records, we noted that OH-GDGTs or GMGTs (or both) are frequently present. The RI-OH, based on OH-GDGTs, recently has been proposed as a temperature proxy in lakes while GMGTs are associated with oxygen-deficient environments. Here we examine distributions of OH-GDGTs and GMGTs in a variety of lakes that also have existing TEX86 or MBT’5ME temperature reconstructions. These lakes range from small to large, shallow to deep, tropical to arctic, differ in oxygenation state, and have sedimentary records covering timespans from the Holocene to multiple glacial-interglacial cycles. Study lakes include El’gygytgyn (arctic Russia), Malawi (tropical southeast Africa), Issyk Kul (Kyrgyzstan), Lake 578 (Greenland), and high elevation lakes in the central Andes (South America). We explore the presence/absence of these compounds in contrasting depositional environments and examine their GDGT distributions in relationship to temperature variability, oxic/anoxic conditions, hydroclimate fluctuations, and other geochemical/environmental parameters. 

Numerous temperature and environmental proxies are based on glycerol dialkylglycerol tetraethers (GDGTs), which are membrane lipids commonly found in thewater columns and sediments of lakes. The TEX86 temperature proxy is based onisoprenoid GDGTs, which are produced by members of the archaea, and is used toreconstruct lake surface temperature. Branched GDGTs are lipids produced bybacteria and form the basis of the MBT′5ME temperature proxy. Although manyoutstanding questions still exist regarding proxies based on isoprenoid and branchedGDGTs, both compound classes have been relatively well-studied in lakes. Morerecently, other types of GDGTs and related compounds are increasingly beingreported from lacustrine sediments including hydroxylated GDGTs (OH-GDGTs) andglycerol monoalkyl glycerol tetraethers (GMGTs). In the process of generating lacustrine TEX86 or MBT′5ME temperature records, we noted that OH-GDGTs orGMGTs (or both) are frequently present. The RI-OH, based on OH-GDGTs, recentlyhas been proposed as a temperature proxy in lakes while GMGTs are associatedwith oxygen-deficient environments. Here we examine distributions of OH-GDGTs and GMGTs in a variety of lakes that also have existing TEX86 or MBT′5ME temperature reconstructions. These lakes range from small to large, shallow to deep,tropical to arctic, differ in oxygenation state, and have sedimentary records coveringtimespans from the Holocene to multiple glacial-interglacial cycles. Study lakesinclude El’gygytgyn (arctic Russia), Malawi (tropical southeast Africa), Issyk Kul(Kyrgyzstan), Lake 578 (Greenland), and high elevation lakes in the central Andes (South America). We explore the presence/absence of these compounds incontrasting depositional environments and examine their GDGT distributions inrelationship to temperature variability, oxic/anoxic conditions, hydroclimatefluctuations, and other geochemical/environmental parameters. 

The Common Era history of effective moisture in the Central Andes is poorly understood, as most Andean proxy records reflect large-scale atmospheric circulation over the South American lowlands rather than localized precipitation vs. evaporation. Here we present 1800-year leaf wax hydrogen and carbon isotope sedimentary records from Lake Chacacocha (13.96°S, 71.08°W, 4,860 m asl.) in the Central Andes. Leaf wax δ2H from different chain lengths offers information about large-scale atmospheric conditions and local-scale effective moisture. Our leaf wax δ2H data record a gradual intensification of the South American summer monsoon (SASM) beginning around ~1250 CE, prior to the external forcings of the Little Ice Age (LIA). Despite peak SASM intensification, our leaf wax δ13C data reveal a locally arid interval between ca. 1600 and 1800 CE. The arid interval was most likely driven by enhanced evaporation and reduced local precipitation, as indicated by the hydrogen isotope fractionation between mid- and long-chain n-alkanes as well as by climate model simulations. Our results help to reconcile conflicting interpretations of the SASM, glacial, and lake-level histories in the Central Andes during the Common Era. 

Climate changes during the mid- to late-Holocene, after the last vestiges of glacial ice sheets dwindled, provide important context for climate change today. In the tropical Andes, most of the continuous paleoclimate records covering the late Holocene are derived from the oxygen isotope composition of ice cores, speleothems, and lake carbonates. These archives are powerful recorders of large-scale changes in circulation and monsoon intensity, but they do not necessarily capture local moisture balance, and so reconstructions of local precipitation and aridity remain scarce. Here we present contrasting histories of local effective moisture vs. regional circulation from several new biomarker records preserved in lakes and peat in the Colombian and Peruvian Andes. We focus on the hydrogen isotope composition of long-chain plant waxes, which reflects precipitation δ2H similarly to δ18O from ice cores and speleothems; and the δ13C of waxes and the δ2H of mid-chain waxes, which reflect local water stress and effective moisture. In both the Northern and Southern Hemisphere tropical Andes, fairly gradual δ2H shifts during the late Holocene indicate a progressive intensification of circulation in the South American lowlands. On the other hand, plant wax δ13C and mid-chain δ2H records indicate abrupt transitions into and out of intervals of water stress and aridity – similar to findings from pollen and sediment lithology from elsewhere in the tropical Andes. We draw on climate models and proxy data syntheses to help reconcile these curiously different accounts of effective moisture in the tropical Andes since the mid-Holocene and discuss implications for modern climate research. 

Abstract The variability of proteins at the sequence level creates an enormous potential for proteome complexity. Exploring the depths and limits of this complexity is an ongoing goal in biology. Here, we systematically survey human and plant high-throughput bottom-up native proteomics data for protein truncation variants, where substantial regions of the full-length protein are missing from an observed protein product. In humans,Arabidopsis, and the green algaChlamydomonas, approximately one percent of observed proteins show a short form, which we can assign by comparison to RNA isoforms as either likely deriving from transcript-directed processes or limited proteolysis. While some detected protein fragments align with known splice forms and protein cleavage events, multiple examples are previously undescribed, such as our observation of fibrocystin proteolysis and nuclear translocation in a green alga. We find that truncations occur almost entirely between structured protein domains, even when short forms are derived from transcript variants. Intriguingly, multiple endogenous protein truncations of phase-separating translational proteins resemble cleaved proteoforms produced by enteroviruses during infection. Some truncated proteins are also observed in both humans and plants, suggesting that they date to the last eukaryotic common ancestor. Finally, we describe novel proteoform-specific protein complexes, where the loss of a domain may accompany complex formation.