Salinity is a severe abiotic stress limiting agricultural yield and productivity. Plants have evolved various strategies to cope with salt stress. Chloroplasts are important photosynthesis organelles, which are sensitive to salinity. An understanding of molecular mechanisms in chloroplast tolerance to salinity is of great importance for genetic modification and plant breeding. Previous studies have characterized more than 53 salt-responsive genes encoding important chloroplast-localized proteins, which imply multiple vital pathways in chloroplasts in response to salt stress, such as thylakoid membrane organization, the modulation of photosystem II (PS II) activity, carbon dioxide (CO₂) assimilation, photorespiration, reactive oxygen species (ROS) scavenging, osmotic and ion homeostasis, abscisic acid (ABA) biosynthesis and signaling, and gene expression regulation, as well as protein synthesis and turnover. This review presents an overview of salt response in chloroplasts revealed by gene characterization efforts.

Agricultural ecosystem formation and evolution depend on interactions and communication between multiple organisms. Within this context, communication occurs between microbes, plants, and insects, often involving the release and perception of a wide range of chemical cues. Unraveling how this information is coded and interpreted is critical to expanding our understanding of how agricultural ecosystems function in terms of competition and cooperation. Investigations examining dual interactions (e.g. plant–microbe, insect–microbe, and insect–plant) have resolved some basic components of this communication. However, there is a need for systematically examining multitrophic interactions that occur simultaneously between microorganisms, insects, and plants. A more thorough understanding of these multitrophic interactions has been made possible by recent advancements in the study of such ecological interactions, which are based on a variety of contemporary technologies such as artificial intelligence sensors, multi‐omics, metabarcoding, and others. Frequently, these developments have led to the discovery of startling examples of each member manipulating the other. Here, we review recent advances in the understanding of bottom‐up chemical communication between microorganisms, plants, and insects, and their consequences. We discuss the components of these “chemo‐languages” and how they modify outcomes of multi‐species interactions across trophic levels. Further, we suggest prospects for translating the current basic understanding of multitrophic interactions into strategies that could be applied in agricultural ecosystems to increase food safety and security.

Tea plant trichomes not only contribute to the unique flavor and high quality of tea products but also provide physical and biochemical defenses for tea plants. Transcription factors play crucial roles in regulating plant trichome formation. However, limited information about the regulatory mechanism of transcription factors underlying tea plant trichome formation is available. Here, the investigation of trichome phenotypes among 108 cultivars of Yunwu Tribute Tea, integrated with a transcriptomics analysis of both hairy and hairless cultivars, revealed the potential involvement of CsGeBPs in tea trichome formation. In total, six CsGeBPs were identified from the tea plant genome, and their phylogenetic relationships, as well as the structural features of the genes and proteins, were analyzed to further understand their biological functions. The expression analysis of CsGeBPs in different tissues and in response to environmental stresses indicated their potential roles in regulating tea plant development and defense. Moreover, the expression level of CsGeBP4 was closely associated with a high-density trichome phenotype. The silencing of CsGeBP4 via the newly developed virus-induced gene silencing strategy in tea plants inhibited trichome formation, indicating that CsGeBP4 was required for this process. Our results shed light on the molecular regulatory mechanisms of tea trichome formation and provide new candidate target genes for further research. This should lead to an improvement in tea flavor and quality and help in breeding stress-tolerant tea plant cultivars.

Leaf color change of variegated leaves from chimera species is regulated by fine-tuned molecular mechanisms. Hosta “Gold Standard” is a typical chimera Hosta species with golden-green variegated leaves, which is an ideal material to investigate the molecular mechanisms of leaf variegation. In this study, the margin and center regions of young and mature leaves from Hosta “Gold Standard”, as well as the leaves from plants after excess nitrogen fertilization were studied using physiological and comparative proteomic approaches. We identified 31 differentially expressed proteins in various regions and development stages of variegated leaves. Some of them may be related to the leaf color regulation in Hosta “Gold Standard”. For example, cytosolic glutamine synthetase (GS1), heat shock protein 70 (Hsp70), and chloroplastic elongation factor G (cpEF-G) were involved in pigment-related nitrogen synthesis as well as protein synthesis and processing. By integrating the proteomics data with physiological results, we revealed the metabolic patterns of nitrogen metabolism, photosynthesis, energy supply, as well as chloroplast protein synthesis, import and processing in various leaf regions at different development stages. Additionally, chloroplast-localized proteoforms involved in nitrogen metabolism, photosynthesis and protein processing implied that post-translational modifications were crucial for leaf color regulation. These results provide new clues toward understanding the mechanisms of leaf color regulation in variegated leaves.

The cellulose synthase gene superfamily, including Cellulose synthase A (CesA) and cellulose synthase-like (Csl) gene families, is responsible for the synthesis of cellulose and hemicellulose, respectively. The CesA/Csl genes are vital for abiotic stress resistance and shoot tenderness regulation of tea plants (Camellia sinensis). However, the CesA/Csl gene family has not been extensively studied in tea plants. Here, we identified 53 CsCesA/Csl genes in tea plants. These genes were grouped into five subfamilies (CsCesA, CsCslB, CsCslD, CsCslE, CsCslG) based on the phylogenetic relationships with Arabidopsis and rice. The analysis of chromosome distribution, gene structure, protein domain and motif revealed that most genes in CsCesA, CsCslD and CsCslE subfamilies were conserved, whereas CsCslB and CsCslG subfamily members are highly diverged. The transcriptome analysis showed that most CsCesA/Csl genes displayed tissue-specific expression pattern. In addition, members of CsCslB4, CsCesA1/3/6, CsCslB3/4, CsCslD3, CsCslE1 and CsCslG2/3 subfamilies were up-regulated under drought and cold stresses, indicating their potential roles in regulating stress tolerance in tea plants. Furthermore, the expression levels of CsCslG2_6 and CsCslD3_5 in different tissues and cultivars, respectively, were positively correlated with the cellulose content that is negatively related with shoot tenderness. Thus, these two genes were speculated to be involved in the regulation of shoot tenderness in tea plants. Our findings may help elucidate the evolutionary relationships and expression patterns of the CsCesA/Csl genes in tea plants, and provide more candidate genes responsible for stress tolerance and tenderness regulation in tea plants for future functional research.