Plant, Cell & Environment最新文献

Phloem plays a major role in plant physiology, health and growth. However, little research has addressed the impact of biotic and abiotic stressors on phloem structure and development. This study extends recent interest on stress impact on phloem to further understand its physiological limits by exploring a common combination of stressors within forest systems: reduced light availability and concomitant foliar pathogenic infection. We compared juvenile Pinus radiata D. Don. plants growing under optimal light conditions to plants growing under reduced light availability and exposure to pathogenic infection. We monitored foliar gas exchange and took destructive samples for nonstructural carbohydrate (NSC) analysis and phloem anatomy in spring and early summer. We used software-assisted image analysis to determine cell composition and area of conducting phloem, and a fluid dynamics model to derive phloem hydraulic parameters. Phloem showed environmental plasticity within the same growing season. We found changes in phloem anatomy in shaded and infected plants, including an increased sieve cell density and permeability, and reduced cell wall thickness. While intrinsic phloem hydraulic efficiency was maintained at the tissue level in stressed plants, the reduction in phloem cross-sectional area resulted in an eventual decline in phloem sap flow rate. Thus, phloem cross-sectional area was dynamically adjusted to match reduced translocation requirements. In addition, shaded and infected plants experienced reduced growth and C assimilation, as well as greater necrotic photosynthetic tissue, but showed similar levels of total NSC than control plants. The high levels of NSC observed in our stressed plants are an important finding that suggests that radial growth cessation and, by association, phloem formation impairment are induced by sink limitation instead of reduced carbohydrate supply to the meristem.

Communication between the diverse compartments of plant cells relies on an intricate network of molecular interactions that orchestrate organellar development and adaptation to environmental conditions. Plastid-to-nucleus signalling pathways play a key role in relaying information from developing, mature, and damaged or disintegrating chloroplasts to the nucleus, which serves to coordinate gene expression between the two genomes. To shed light on these mechanisms, we performed a comprehensive analysis of the response of the Arabidopsis thaliana proteomes to perturbation of chloroplast biogenesis by the antibiotic lincomycin (Lin) in the absence of GENOMES UNCOUPLED 1 (GUN1), a key player in plastid-to-nucleus signalling. The topological analysis of protein-protein interactions (PPIs) and co-expression networks enabled the identification of protein hubs in each genotype and condition tested, and highlighted whole-cell adaptive responses to the disruption of chloroplast biogenesis. Our findings reveal a novel role for PsbO, a subunit of the oxygen-evolving complex (OEC), which behaves as an atypical photosynthetic protein upon inhibition of plastid protein synthesis. Notably, and unlike all other subunits of the thylakoid electron transport chain, PsbO accumulates in non-photosynthetic plastids, and is crucial for the breakdown of damaged chloroplasts.

We investigate how soil and atmospheric droughts jointly impact tree growth and recovery dynamics in a semi-arid pine forest, leveraging high-resolution stem diameter variation data and an irrigation experiment. The irrigated plot, where soil drought was mitigated, served as a benchmark to isolate the effects of atmospheric drought and distinguish them from the compound drought conditions experienced by control trees. Using a suite of tools based only on stem diameter variation, we identified growth modes that vary in accordance with soil water availability. Control trees showed negligible growth during the dry season but rapidly recovered with the onset of the wet season, matching the baseline growth rates of the irrigated trees, suggesting minimal compromise in hydraulic functioning. Our main finding is that heatwaves consistently depress stem-expansion rates, regardless of treatment. However, during the dry season, this negative impact diverges sharply between the treatments. Because irrigated trees benefit from a hydraulic buffer supplied by ample soil water and thus retain a positive growth baseline, the depression merely slows their expansion, whereas control trees already near zero are driven into net contraction. These findings offer new understanding of how trees balance growth, contraction, and recovery under varying drought conditions, revealing the pivotal role of soil water in shaping drought responses across seasons. As climate change intensifies the frequency and severity of drought events, this knowledge is critical for anticipating shifts in tree growth and resilience.

Panicle architecture is a critical determinant of rice yield and resilience, yet the genetic and environmental factors shaping this trait remain incompletely understood. Here, we applied an integrative genomic approach combining multi-locus association mapping, transcriptome analysis and population genomics to dissect the genetic basis of key panicle traits in rice. We identified robust genetic loci underlying the number of primary branches, panicle length and spikelets per panicle, with many showing sensitivity to temperature, underscoring the importance of gene-environment interactions for yield stability. Notably, we discovered that variation in alternative polyadenylation (APA) of specific transcripts is associated with panicle trait diversity at the population level, suggesting that regulatory mechanisms such as APA are significant contributors to phenotypic plasticity and adaptation. These findings deliver both novel candidate genes in panicle development and mechanistic insights to support the breeding of rice varieties with enhanced productivity and climate resilience.

Global climate change exacerbates the impact of environmental stressors such as drought, salinity and extreme temperatures on crop growth and grain yield, endangering the sustainability of the food supply. Soybean (Glycine Max [L.] Merr.) is an important legume crop and plays a crucial role in the global food supply chain and food security, and contributes the substantial protein content relative to other crops. However, soybean yield stability is critically dependent on the plant's adaptive responses to abiotic stress factors, particularly drought, salinity and temperature extremes, which primarily impact its growth and productivity. Recently, various molecular techniques, including genetic engineering, transcriptomics, transcription factor analysis, CRISPR/Cas9, and conventional methods, have been employed to elucidate the molecular mechanisms of soybean responses to environmental stresses for the breeding of tolerant cultivars of soybean. This review summarises recent advances in dissecting the genetic factors and networks that contribute to soybean abiotic stress tolerance through diverse strategies. We also discuss future challenges and opportunities for the development of climate-resilient soybean varieties. Consequently, the updated review will serve as a comprehensive guideline for researchers investigating the genetic mechanism of abiotic stress in soybean.

Global warming impacts several aspects of plant physiology, with important negative effects on crop yield and production of secondary metabolites, such as anthocyanins. The anthocyanin content of vegetables and fruits has attracted public interest in the last two decades due to its health benefits, leading to the development of novel anthocyanin-enriched plant varieties, including purple tomato lines. In purple tomato fruits anthocyanin biosynthesis is largely regulated by light through HY5, whose levels are in turn controlled by COP1-targeted destabilization, and increasing temperatures strongly impair anthocyanin accumulation in the fruit peel. Interestingly, two different COP1-encoding genes exist in tomato and one of them is further involved in alternative splicing, giving origin to polypeptides characterized by different lengths and, possibly, functions. High temperatures trigger HY5 degradation under light through nuclear relocation and interaction with DET1 of both COP1 tomato factors. high pigment 2 (hp2) tomato plants bear a nonfunctional det1 allele and show exacerbate photomorphogenesis due to HY5 stabilization. In this paper, we show that the COP1-DET1-HY5 switch is crucial for the high temperature-induced repression of anthocyanin synthesis in purple fruits. The loss of DET1 indeed impedes COP1 activity in degrading HY5, allowing sustained anthocyanin accumulation under light even under high temperatures. All COP1 tomato factors seem to require DET1 to target HY5 to proteolysis, but only COP1-like X1 isoform gene is also transcriptionally regulated by HY5, whereas the expression of COP1 homolog is not affected by the mutation of DET1. Furthermore, whereas the expression of COP1 homolog is stable and independent from temperature, the canonical transcript of COP1-like X1 isoform, possibly producing the polypeptide containing all the functional domains, is also enhanced by higher temperatures. The introgression of the hp2 mutation in purple tomato lines can thus counteract the high temperature-induced reduction in anthocyanin accumulation, representing a key strategy to preventing global warming-related loss of quality in tomatoes.

The long-lived angiosperm Quercus L. (Oaks) have emerged as promising model organisms for investigating adaptive divergence and ecological environmental interactions due to their longevity and large genetic diversity as well as recurrent gene flow among species with diverse natural habitats. Until recently, numerous genomic studies by new high-throughput sequencing platforms have provided access to link genes with ecological and physiological traits. However, the genetic and epigenetic mechanisms underlying the adaptive evolution of oak trees are still poorly understood. In this review, we summarise the current progress of reported oak genomes and inheritance systems, analysing the epigenetics and genetic structure of oaks. We review evidence regarding the genetic mechanism linking introgressive hybridisation and reproductive isolation for a better understanding of adaptive divergence and defining speciation in oaks. Furthermore, we also discuss the interaction and evolution between oaks, other organisms and the environment to explore the adaptive strategies and coevolutionary mechanisms among them. Through the impact of this article, hopefully, a distinctive avenue could be established to further study the inheritance, ecology and multidimensional evolution of oaks.

Photosynthesis in plants is negatively affected by high light intensity and UV radiation. The photoreceptors UV RESISTANCE LOCUS 8 (UVR8) and CRYPTOCHROMES (CRYs) mediate perception and acclimation of plants to UV-B/UV-A2 (290-340 nm) and UV-A1/blue light (350-500 nm), respectively. However, their roles in photoprotection of photosynthesis across different wavebands of the spectrum remain unclear. Using chlorophyll fluorescence and LED lighting we studied the roles of UVR8 and CRYs in maintaining photosynthetic capacity in Arabidopsis exposed to UV-B, UV-A1, and blue light. Analysis of quantum yield of Photosystem II, nonphotochemical quenching, and LHCII phosphorylation demonstrated that CRYs preserve photosynthetic performance in plants exposed to UV-B, UV-A1, and blue light. UVR8 and CRYs exhibit partially redundant functions in maintaining photosynthetic activity under UV-B, UV-A1, and blue light, and in preventing photodamage under high UV-A1 irradiance. Impaired UVR8 and CRY signalling reduced epidermal flavonol accumulation in leaves, which further compromised photoprotection. These findings provide valuable insights into how UV and blue light perception contribute to photoprotection, with broad implications for plant performance both in natural and managed environments.