High light and temperature reduce photosynthetic efficiency through different mechanisms in the C4 model Setaria viridis.

Funder: start-up funding from Donald Danforth Plant Science CenterC4 plants frequently experience high light and high temperature conditions in the field, which reduce growth and yield. However, the mechanisms underlying these stress responses in C4 plants have been under-explored, especially the coordination between mesophyll (M) and bundle sheath (BS) cells. We investigated how the C4 model plant Setaria viridis responded to a four-hour high light or high temperature treatment at photosynthetic, transcriptomic, and ultrastructural levels. Although we observed a comparable reduction of photosynthetic efficiency in high light or high temperature treated leaves, detailed analysis of multi-level responses revealed important differences in key pathways and M/BS specificity responding to high light and high temperature. We provide a systematic analysis of high light and high temperature responses in S. viridis, reveal different acclimation strategies to these two stresses in C4 plants, discover unique light/temperature responses in C4 plants in comparison to C3 plants, and identify potential targets to improve abiotic stress tolerance in C4 crops

Hardware in the loop simulation of helicopter PinS procedures using GLS avionics and an SBAS to GLS converter

We designed and built a system intended to combine the advantages of both the ground based and the satellite-based augmentation systems (GBAS, SBAS) by using a converter between them. In both GBAS and SBAS, instant integrity information is provided by estimating protection levels, a high probability bound for the computed position. This is then compared to the alert limit of the respective system. Since both systems are quite similar, and the SBAS signal can nowadays be decoded even by low cost receivers, one can receive the augmentation data from the SBAS, slightly modify it to fit into the GBAS data structure and broadcast this data to a GBAS equipped aircraft. Said aircraft could execute an RNP approach with the Localizer Performance and Vertical guidance (LPV) final approach segment which would otherwise not be available. This may come especially handy in places where no non-precision minima are published, such as the RNP-E approach into Innsbruck and Salzburg, or where no other approach procedures are available to spatial or monetary constraints. Since there are slight differences between the two systems, we made sure that integrity for the safety-of-life approach service is ensured. We named the system GLASS (GLS Approaches using SbaS), built a prototype and began trials with real GBAS avionics hardware. To accomplish this, we created a hardware in the loop environment, which allows us to validate various receivers without having to go through a full flight certification of the hardware. We tested this environment using the DLR in house full motion rotorcraft simulator to fly point in space approaches during Helicopter Emergency Service (HEMS) missions. The test bench setup consists of an Orolia GSG5 GPS and SBAS simulator connected to both an SBAS receiver and a Funke Avionics GPU400 GLS receiver. The SBAS receiver is subsequently connected to a GLASS Station PC, which translates the SBAS corrections to GLS conformal structures and broadcasts them using a Telerad 9009 VDB GLS transmitter. This transmitter is also connected to the VHF data broadcast input of the GPU4000. The Orolia GSG5 receives data updates from the DLR flight simulator Aves (Figure 1). During the trials, the accuracy and integrity of both receivers behaved as expected. However, the Collins GLU925 showed an anomaly: if two corrections were broadcast with the same IODE parameter, the second one was ignored. This limits the availability of the system unnecessarily. Moreover, we found that both digital avionics devices did not evaluate the approach performance designator, one parameter of the final approach segment date block. This actually increases integrity while also limiting availability at the same time

Role of an ancient light-harvesting protein of PSI in light absorption and photoprotection

Diverse algae of the red lineage possess chlorophyll a-binding proteins termed LHCR, comprising the PSI light-harvesting system, which represent an ancient antenna form that evolved in red algae and was acquired through secondary endosymbiosis. However, the function and regulation of LHCR complexes remain obscure. Here we describe isolation of a Nannochloropsis oceanica LHCR mutant, named hlr1, which exhibits a greater tolerance to high-light (HL) stress compared to the wild type. We show that increased tolerance to HL of the mutant can be attributed to alterations in PSI, making it less prone to ROS production, thereby limiting oxidative damage and favoring growth in HL. HLR1 deficiency attenuates PSI light-harvesting capacity and growth of the mutant under light-limiting conditions. We conclude that HLR1, a member of a conserved and broadly distributed clade of LHCR proteins, plays a pivotal role in a dynamic balancing act between photoprotection and efficient light harvesting for photosynthesis. LHCR proteins are ancient chlorophyll a-binding antennas that evolved in diverse algae of the red lineage. Here Lu et al. characterize a red lineage LHCR mutant and show reduced oxidative damage in high light but attenuated growth under low light, thus demonstrating how LHCR proteins impact the balance between photoprotection and light harvesting

ACROSS: Reference Scenarios

This document is the Deliverable D1.4-1 Reference Scenarios of ACROSS, a European 7th Framework EC funded project. The main purpose of ACROSS is: · To develop, integrate and test new cockpit solutions that facilitate the management of the peak workload situations that can occur during a flight, in order to improve safety and ensure the reduction of accident risks through the reduction of stress; · To develop, integrate and test new cockpit solutions that will allow reduced crew operations in a limited number of well-defined conditions; · To identify the remaining open issues for the implementation of single pilot operations, taking into account first learning about evaluations done on workload reduction and reduced crew operations. Deliverable 1.4-1 presents a collection of scenarios that have been selected as relevant for the ACROSS project. Those scenarios will be refined for the purposes of validation and embedded in a global validation scenario in the framework of WP11 Validation and Global Assessment. Here, the scenarios are initially analysed with respect to their generation of high workload for the flight deck crew. The document also refers to the first two ACROSS objectives and defines 4 distinct configurations (Fully Capacitated Crew under peak workload, Intentionally Reduced Crew, Unintentionally Reduced Crew and Fully Incapacitated Crew) that will be dealt with in the frame of the project. Within each configuration, the situation of the flight crew is further specified as a normal, abnormal trained and abnormal untrained situation. All scenarios are related to one or more phases of flight that are considered within the scope of ACROSS

Metabolomic, photoprotective, and photosynthetic acclimatory responses to post-flowering drought in sorghum.

Climate change is globally affecting rainfall patterns, necessitating the improvement of drought tolerance in crops. Sorghum bicolor is a relatively drought-tolerant cereal. Functional stay-green sorghum genotypes can maintain green leaf area and efficient grain filling during terminal post-flowering water deprivation, a period of ~10 weeks. To obtain molecular insights into these characteristics, two drought-tolerant genotypes, BTx642 and RTx430, were grown in replicated control and terminal post-flowering drought field plots in Californias Central Valley. Photosynthetic, photoprotective, and water dynamics traits were quantified and correlated with metabolomic data collected from leaves, stems, and roots at multiple timepoints during control and drought conditions. Physiological and metabolomic data were then compared to longitudinal RNA sequencing data collected from these two genotypes. The unique metabolic and transcriptomic response to post-flowering drought in sorghum supports a role for the metabolite galactinol in controlling photosynthetic activity through regulating stomatal closure in post-flowering drought. Additionally, in the functional stay-green genotype BTx642, photoprotective responses were specifically induced in post-flowering drought, supporting a role for photoprotection in the molecular response associated with the functional stay-green trait. From these insights, new pathways are identified that can be targeted to maximize yields under growth conditions with limited water

Metabolomic, photoprotective, and photosynthetic acclimatory responses to post‐flowering drought in sorghum

Abstract Climate change is globally affecting rainfall patterns, necessitating the improvement of drought tolerance in crops. Sorghum bicolor is a relatively drought‐tolerant cereal. Functional stay‐green sorghum genotypes can maintain green leaf area and efficient grain filling during terminal post‐flowering water deprivation, a period of ~10 weeks. To obtain molecular insights into these characteristics, two drought‐tolerant genotypes, BTx642 and RTx430, were grown in replicated control and terminal post‐flowering drought field plots in California's Central Valley. Photosynthetic, photoprotective, and water dynamics traits were quantified and correlated with metabolomic data collected from leaves, stems, and roots at multiple timepoints during control and drought conditions. Physiological and metabolomic data were then compared to longitudinal RNA sequencing data collected from these two genotypes. The unique metabolic and transcriptomic response to post‐flowering drought in sorghum supports a role for the metabolite galactinol in controlling photosynthetic activity through regulating stomatal closure in post‐flowering drought. Additionally, in the functional stay‐green genotype BTx642, photoprotective responses were specifically induced in post‐flowering drought, supporting a role for photoprotection in the molecular response associated with the functional stay‐green trait. From these insights, new pathways are identified that can be targeted to maximize yields under growth conditions with limited water