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On a global scale, drought, salinity, extreme temperature, and other abiotic stressors severely limit the quality and yield of crops. Therefore, it is crucial to clarify the adaptation strategies of plants to harsh environments. Chloroplasts are important environmental sensors in plant cells. For plants to thrive in different habitats, chloroplast homeostasis must be strictly regulated, which is necessary to maintain efficient plant photosynthesis and other metabolic reactions under stressful environments. To maintain normal chloroplast physiology, two important biological processes are needed: the import and degradation of chloroplast proteins. The orderly import of chloroplast proteins and the timely degradation of damaged chloroplast components play a key role in adapting plants to their environment. In this review, we briefly describe the mechanism of chloroplast TOC-TIC protein transport. The importance and recent progress of chloroplast protein turnover, retrograde signaling, and chloroplast protein degradation under stress are summarized. Furthermore, the potential of targeted regulation of chloroplast homeostasis is emphasized to improve plant adaptation to environmental stresses.

Resistive random access memory (RRAM) crossbar arrays require the highly nonlinear selector with high current density to address a specific memory cell and suppress leakage current through the unselected cell. 3D monolithic integration of RRAM array requires selector devices with a small footprint and low‐temperature processing for ultrahigh‐density data storage. Here, an ultrathin two‐terminal n‐p‐n selector with 2D transition metal dichalcogenides (TMDs) is designed by a low‐temperature transfer method. The van der Waals contact between transferred Au electrodes and TMDs reduces the Fermi level pinning and retains the intrinsic transport behavior of TMDs. The selector with a single type of TMD exhibits a trade‐off between current density and nonlinearity depending on the barrier height. By tuning the Schottky barrier height and controlling the thickness of p‐type WSe2 in MoS2/WSe2/MoS2 n‐p‐n selector for a punch‐through transport, the selector shows high nonlinearity (≈ 230) and high current density (2 × 103 A cm−2) simultaneously. The n‐p‐n selectors are further integrated with a bipolar hexagonal boron nitride memory and calculate the maximum crossbar size of the 2D material‐based one‐selector one‐resistor according to a 10% read margin, which offers the possible realization of future 3D monolithic integration. [ABSTRACT FROM AUTHOR]

The bacterial enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase plays a key role in lowering plant stress ethylene levels, thereby stimulating plant growth. The present study aims to evaluate whether the ACC deaminase producing plant growth promoting rhizobacterium (PGPR) Pseudomonas putida UW4 can maintain and promote plant growth in saline environments and modulate the expression of chloroplast import apparatus genes in salt-treated tomato plants (Solanum lycopersicum L.). Tomatoes were grown in the presence and absence of the PGPR and shoot length, fresh and dry mass, and chlorophyll concentration were measured after 6 weeks. The expression levels of the Toc GTPases of the chloroplast protein import apparatus were measured using quantitative real-time PCR. The results showed that the rhizobacteria significantly increased shoot length, shoot fresh and dry mass, and the chlorophyll concentration of tomato seedlings grown in the presence of up to 90 mmol x [L.sup.-1] NaCl. Analysis showed that the expression of most of the Toc GTPase genes was upregulated in tomato seedlings after 6 weeks of exposure to NaCl, which may help facilitate the import into chloroplasts of proteins that are involved in the stress response. Key words: rhizobacteria, ACC deaminase, tomato, Toc GTPases, salt stress. La 1-aminocyclopropane-1-carboxylate (ACC) desaminase, une enzyme bacterienne, joue un role cle dans la diminution des niveaux d'ethylene associes au stress chez les vegetaux, stimulant ainsi leur croissance. L'etude presente visait a evaluer si Pseudomonas putida UW4, une rhizobacterie favorisant la croissance des plantes (RFCP) qui produit de l'ACC desaminase, peut maintenir et favoriser la croissance des plantes dans des environnements salins, et moduler l'expression des genes codant les constituantes du complexe d'import chloroplastique chez des plants de tomates (Solanum lycopersicum L.) traites au sel. Les plants de tomates ont ete cultives en presence ou en absence de RFCP, et la longueur, les poids frais et sec et la concentration de chlorophylle des pousses ont ete mesures apres 6 semaines. Les niveaux d'expression des Toc GTPases du complexe proteique d'import du chloroplaste ont aussi ete mesures par PCR quantitative en temps reel. Les resultats ont montre que les rhizobacteries accroissaient significativement la longueur des pousses, les poids frais et sec des pousses et la concentration de chlorophylle des semis de tomates cultives en presence de NaCl allant jusqu'a 90 mmol.[L.sup.-1]. L'analyse d'expression montrait que l'expression de la plupart des genes des Toc GTPases est regulee a la hausse dans les semis de tomates apres 6 semaines d'exposition au NaCl, ce qui peut faciliter l'import dans le chloroplaste de proteines impliquees dans la reponse au stress. [Traduit par la Redaction] Mots-cles: rhizobacteries, ACC desaminase, tomate, Toc GTPases, stress salin., Introduction In plants, salt stress can lead to osmotic and ionic stress, impairing vital cellular functions and leading to changes in morphology and physiology. Such changes can affect a plant's [...]

The translocon at the outer envelope membrane of chloroplasts (Toc) mediates the recognition and initial import into the organelle of thousands of nucleus-encoded proteins. These proteins are translated in the cytosol as precursor proteins with cleavable amino-terminal targeting sequences called transit peptides. The majority of the known Toc components that mediate chloroplast protein import were originally identified in pea, and more recently have been studied most extensively in Arabidopsis. With the completion of the tomato genome sequencing project, it is now possible to identify putative homologues of the chloroplast import components in tomato. In the work reported here, the Toc GTPase cDNAs from tomato were identified, cloned and analyzed. The analysis revealed that there are four Toc159 homologues (slToc159-1, -2, -3 and -4) and two Toc34 homologues (slToc34-1 and -2) in tomato, and it was shown that tomato Toc159 and Toc34 homologues share high sequence similarity with the comparable import apparatus components from Arabidopsis and pea. Thus, tomato is a valid model for further study of this system. The expression level of Toc complex components was also investigated in different tissues during tomato development. The two tomato Toc34 homologues are expressed at higher levels in non-photosynthetic tissues, whereas, the expression of two tomato Toc159 homologues, slToc159-1 and slToc159-4, were higher in photosynthetic tissues, and the expression patterns of slToc159-2 was not significantly different in photosynthetic and non-photosynthetic tissues, and slToc159-3 expression was limited to a few select tissues. [ABSTRACT FROM AUTHOR]

The translocon at the outer envelope membrane of chloroplasts (Toc) mediates the recognition and initial import into the organelle of thousands of nucleus-encoded proteins. These proteins are translated in the cytosol as precursor proteins with cleavable amino-terminal targeting sequences called transit peptides. The majority of the known Toc components that mediate chloroplast protein import were originally identified in pea, and more recently have been studied most extensively in Arabidopsis. With the completion of the tomato genome sequencing project, it is now possible to identify putative homologues of the chloroplast import components in tomato. In the work reported here, the Toc GTPase cDNAs from tomato were identified, cloned and analyzed. The analysis revealed that there are four Toc159 homologues (slToc159-1, -2, -3 and -4) and two Toc34 homologues (slToc34-1 and -2) in tomato, and it was shown that tomato Toc159 and Toc34 homologues share high sequence similarity with the comparable import apparatus components from Arabidopsis and pea. Thus, tomato is a valid model for further study of this system. The expression level of Toc complex components was also investigated in different tissues during tomato development. The two tomato Toc34 homologues are expressed at higher levels in non-photosynthetic tissues, whereas, the expression of two tomato Toc159 homologues, slToc159-1 and slToc159-4, were higher in photosynthetic tissues, and the expression patterns of slToc159-2 was not significantly different in photosynthetic and non-photosynthetic tissues, and slToc159-3 expression was limited to a few select tissues. [ABSTRACT FROM AUTHOR]

The demand for accurate perception of the physical world leads to a dramatic increase in sensory nodes. However, the transmission of massive and unstructured sensory data from sensors to computing units poses great challenges in terms of power-efficiency, transmission bandwidth, data storage, time latency, and security. To efficiently process massive sensory data, it is crucial to achieve data compression and structuring at the sensory terminals. In-sensor computing integrates perception, memory, and processing functions within sensors, enabling sensory terminals to perform data compression and data structuring. Here, vision sensors are adopted as an example and discuss the functions of electronic, optical, and optoelectronic hardware for visual processing. Particularly, hardware implementations of optoelectronic devices for in-sensor visual processing that can compress and structure multidimensional vision information are examined. The underlying resistive switching mechanisms of volatile/nonvolatile optoelectronic devices and their processing operations are explored. Finally, a perspective on the future development of optoelectronic devices for in-sensor computing is provided., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)

Perovskite oxides with luminescent ions hold great promise in optoelectronic devices because of their outstanding thermal stabilities and electro-optic performance. As one typical perovskite upconversion (UC) host material, lead-free potassium sodium niobate ((K, Na)NbO3/(KxNa1-x)NbO3 or KNN) has attracted much attention in recent years. In the present work, a novel routine was developed to tune the upconversion photoluminescence (UC PL) performance by controlling the oxygen vacancy concentration in the KNN matrix, based on the 0.1% Er3+-doped KNN (Er-KNN) single crystals grown for the first time. UC PL properties, conductivity and defect chemistry of the single crystals were systematically investigated. The UC PL intensity of the as-grown Er-KNN material could be enhanced by 20 times after oxygen atmosphere annealing at 800 °C and fully quenched after vacuum annealing. What's more, by annealing under an oxygen atmosphere and vacuum, the conductivity of the Er-KNN sample was successfully tuned for more than 8 orders of magnitude. The super-wide range tunability of UC PL performance and conductivity could be explained by oxygen vacancies which gave rise to Nb5+-Nb4+ valence alternation. Because of the modulated photoluminescence properties and conductivity, our grown Er-KNN single crystals have great potential for use in multifunctional devices.