New Phytologist最新文献

Carotenoids, once biosynthesised, participate in a range of processes within plants including serving as precursors for the biosynthesis of multiple hormones, acting as signalling molecules and apocarotenoid aroma compounds, as well as playing roles in the stabilisation of photosystems and acting as antioxidants. These functions contribute to a high turnover rate of carotenoids within leaves (Beisel et al., 2010). Another facet of carotenoids is in attracting insects and animals to facilitate successful reproduction and seed dispersal due to their vibrant colours and presence in fruits and flowers. However, this process relies upon their stable storage in the plastids of non-photosynthetic tissue. The quantity and composition of carotenoids is highly species and variety specific, but generally, the total carotenoid content correlates to the colour intensity in these organs. The esterification of xanthophylls (oxygenated carotenoids) to fatty acids positively influences total carotenoid accumulation by enhancing their packaging into specialised structures within plastids, called plastoglobules. Esterification also likely protects xanthophylls from catabolism through steric hindrance of enzymes that catalyse carotenoid cleavage, such as the carotenoid cleavage dioxygenases and the 9-cis-epoxycarotenoid dioxygenases, although this remains to be demonstrated. Despite the positive influence on total carotenoid accumulation, we are only beginning to understand the molecular mechanisms involved in xanthophyll ester production.

Using a comprehensive set of experiments, Li et al. unravel the genetic basis of esterification in rapeseed flowers. Through a combination of map-based cloning, loss-of-function studies using CRISPR/Cas9 technology and genetic complementation, two homologous genes from the esterase/lipase/thioesterase (ELT) family of acyltransferases were identified that function redundantly to direct petal colour formation and are annotated as xanthophyll esterases. The authors used liquid chromatography coupled with UV/vis spectroscopy and high-resolution mass spectroscopy to identify individual xanthophyll ester species, an undertaking which is notoriously difficult (Mercadante et al., 2017). Interestingly, in white petals of both a naturally occurring cultivar and the xanthophyll esterase double knockout line, pcs, not only are esterified xanthophylls absent, but total carotenoid content is greatly reduced, signifying that in addition to biosynthesis, the stable storage and protection of carotenoids from turnover is required to produce the vivid yellow petal phenotype. The authors further probed the metabolome and transcriptome of the xanthophyll esterase double mutant line pcs and discovered that in the white petals of the mutant, metabolic flux is redirected to lipid metabolism and storage. They also observed no change in the expression of carotenoid biosynthesis ge

The development of insecticidal chemicals (commonly termed pesticides) has revolutionized the process of cultivation in agriculture; yet, similarly to the development of antimicrobial resistance in pathogens, insects can rapidly develop resistance to these chemicals (Alyokhin & Chen, 2017). Pesticides can also negatively affect beneficial insects such as pollinators and natural enemies of herbivorous insects (Bourguet & Guillemaud, 2016). Extensive pesticide use also poses risks to farmers and growers who apply the pesticides, as well as consumers who eat the resulting produce (Del Prado-Lu, 2015; Bourguet & Guillemaud, 2016). Additionally, pesticides are not always cheap, increasing the economic burden on farmers and consumers alike (Bourguet & Guillemaud, 2016). As a result, alternative strategies are needed to control major crop pests whose damage affects yield and crop quality. A key component of integrated pest management (IPM) is the identification of extant crop varieties carrying resistance phenotypes against pest insects (Stenberg, 2017), in particular, the identification of varieties or lines that emit deterrent volatile organic compounds (VOCs), which can stop pest insects at the source by preventing physical contact, oviposition, and feeding on vulnerable crops. However, rather than killing the insects once a plant is infested, or in the early stages of infestation, why not just keep the insects from infesting in the first place? An exciting study by Ghosh et al., published in this issue of New Phytologist (2023, 1259–1274) identifies a variety of eggplant (aubergine/brinjal) (Solanum melongena L., Solanaceae) resistant to the eggplant/brinjal shoot and fruit borer (Lucinodes orbonalis Guenée, Lepidoptera: Pyralidae), which infests both the vegetative and fruit tissues of the plant (Fig. 1).

This eggplant variety, which originates in the eastern Himalaya region, shows nearly complete resistance to infestation by the adult moth of L. orbonalis, with a complete lack of infested fruits and shoots, and very limited presence of moth eggs on the leaves of the plant – the moth's usual oviposition site. The identification of a naturally resistant variety of eggplant is exciting news, as the pest moth is found world-wide and can cause the loss of 45–100% of marketable fruit (Reshma et al., 2019). As a result of this heavy infestation and loss potential, eggplant receives some of the heaviest pesticide burdens of any cultivated species, with plants sprayed up to 20 times per month in some locations (Del Prado-Lu, 2015). The presence of these pesticides affects not only the moths, but also potentially beneficial insects such as pollinators and parasitoid wasps. Eggplant is largely self-pollinated but benefits from pollination for seed set and fruit production (Pess

The plant immune system features numerous immune receptors localized on the cell surface to monitor the apoplastic space for danger signals from a broad range of plant colonizers. Recent discoveries shed light on the enormous complexity of molecular signals sensed by these receptors, how they are generated and removed to maintain cellular homeostasis and immunocompetence, and how they are shaped by host-imposed evolutionary constraints. Fine-tuning receptor sensing mechanisms at the molecular, cellular and physiological level is critical for maintaining a robust but adaptive host barrier to commensal, pathogenic, and symbiotic colonizers alike. These receptors are at the core of any plant-colonizer interaction and hold great potential for engineering disease resistance and harnessing beneficial microbiota to keep crops healthy.

The endomembrane system consists of various membrane-bound organelles including the endoplasmic reticulum (ER), Golgi apparatus, trans-Golgi network (TGN), endosomes, and the lysosome/vacuole. Membrane trafficking between distinct compartments is mainly achieved by vesicular transport. As the endomembrane compartments and the machineries regulating the membrane trafficking are largely conserved across all eukaryotes, our current knowledge on organelle biogenesis and endomembrane trafficking in plants has mainly been shaped by corresponding studies in mammals and yeast. However, unique perspectives have emerged from plant cell biology research through the characterization of plant-specific regulators as well as the development and application of the state-of-the-art microscopical techniques. In this review, we summarize our current knowledge on the plant endomembrane system, with a focus on several distinct pathways: ER-to-Golgi transport, protein sorting at the TGN, endosomal sorting on multivesicular bodies, vacuolar trafficking/vacuole biogenesis, and the autophagy pathway. We also give an update on advanced imaging techniques for the plant cell biology research.

Age-related resistance to microbe invasion is a commonly accepted concept in plant pathology. However, the impact of such age-dependent interactive phenomena is perhaps not yet sufficiently recognized by the broader plant science community. Toward cataloging an understanding of underlying mechanisms, this review explores recent molecular studies and their relevance to the concept. Examples describe differences in genetic background, transcriptomics, hormonal balances, protein-mediated events, and the contribution by short RNA-controlled gene silencing events. Throughout, recent findings with viral systems are highlighted as an illustration of the complexity of the interactions. It will become apparent that instead of uncovering a unifying explanation, we unveiled only trends. Nevertheless, with a degree of confidence, we propose that the process of plant age-related defenses is actively regulated at multiple levels. The overarching goal of this control for plants is to avoid a constitutive waste of resources, especially at crucial metabolically draining early developmental stages.