Stress biology最新文献

Cadmium (Cd) intake poses a significant health risk to humans, and the contamination of rice grains with Cd is a major concern in regions where rice is a staple food. Although the knockout of OsNRAMP5, which encodes a key transporter responsible for Cd and manganese (Mn) uptake, can significantly reduce Cd accumulation in rice grains, recent studies have revealed that this knockout adversely affects plant growth, grain yield, and increases vulnerability to abiotic and biotic stresses due to reduced Mn accumulation. In this study, we employed CRISPR/Cas9 technology to modify the regulatory region of OsNRAMP5 with the aim of reducing Cd accumulation in rice grains. Our findings demonstrate that mutations in the regulatory region of OsNRAMP5 do not impact its expression pattern but result in a reduction in translation. The decreased translation of OsNRAMP5 effectively decreases grain Cd accumulation while leaving Mn accumulation and important agronomic traits, including yield, unaffected. Thus, our study presents a practical and viable strategy for reducing Cd accumulation in rice grains without compromising Mn accumulation or overall rice production.

Ralstonia solanacearum is a soil-borne bacterium that causes bacterial wilt disease in over 250 plant species. It has been identified as one of the top ten most serious plant pathogenic bacteria globally, causing significant crop yield loss every year. Despite its large impact on agricultural economics, the molecular mechanisms underlying plant defense against Ralstonia infection and by which Ralstonia grows within the plant xylem remain largely unexplored. In a recent article, Ke et al. discovered a distinct pathogen effector, which acted as an immune elicitor in plants but also played dual roles in compromising plant immune activation and increasing nutrient acquisition from the host plants for pathogen propagation.

Recently, Kidokoro et al. found that protein complex LNK3,4-RVE4,8 and LNK1,2-RVE4,8 of the circadian clock modulates plant cold- and high-temperature tolerance, respectively. Here, we reviewed the discovery of LNKs, the dynamically formed morning-phased clock complexes, and their critical role on endogenous circadian rhythms. In addition, we summarized the research work on LNKs with the interacting proteins RVEs, CCA1 in temperature responses and discussed how the circadian clock confer increased fitness via gating the rhythmic expression of their target genes.

Plant hormones are important for regulating growth, development, and plant-pathogen interactions. Some of them are inhibitory to growth of fungal pathogens but the underlying mechanism is not clear. In this study, we found that hyphal growth of Fusarium graminearum was significantly reduced by high concentrations of IAA and its metabolically stable analogue 2,4-dichlorophenoxyacetic acid (2,4-D). Besides inhibitory effects on growth rate, treatments with 2,4-D also caused significant reduction in conidiation, conidium germination, and germ tube growth. Treatments with 2,4-D had no obvious effect on sexual reproduction but significantly reduced TRI gene expression, toxisome formation, and DON production. More importantly, treatments with 2,4-D were inhibitory to infection structure formation and pathogenesis at concentrations higher than 100 µM. The presence of 1000 µM 2,4-D almost completely inhibited plant infection and invasive growth. In F. graminearum, 2,4-D induced ROS accumulation and FgHog1 activation but reduced the phosphorylation level of Gpmk1 MAP kinase. Metabolomics analysis showed that the accumulation of a number of metabolites such as glycerol and arabitol was increased by 2,4-D treatment in the wild type but not in the Fghog1 mutant. Transformants expressing the dominant active FgPBS2^{S451D T455D} allele were less sensitive to 2,4-D and had elevated levels of intracellular glycerol and arabitol induced by 2,4-D in PH-1. Taken together, our results showed that treatments with 2,4-D interfere with two important MAP kinase pathways and are inhibitory to hyphal growth, DON biosynthesis, and plant infection in F. graminearum.

The majority of native cattle are taurine × indicine cattle of diverse phenotypes in the central region of China. Sanjiang cattle, a typical breed in the central region, play a central role in human livelihood and have good adaptability, including resistance to dampness, heat, roughage, and disease, and are thus regarded as an important genetic resource. However, the genetic history of the successful breed remains unknown. Here, we sequenced 10 Sanjiang cattle genomes and compared them to the 70 genomes of 5 representative populations worldwide. We characterized the genomic diversity and breed formation process of Sanjiang cattle and found that Sanjiang cattle have a mixed ancestry of indicine (55.6%) and taurine (33.2%) dating to approximately 30 generations ago, which has shaped the genome of Sanjiang cattle. Through ancestral fragment inference, selective sweep and transcriptomic analysis, we identified several genes linked to lipid metabolism, immune regulation, and stress reactions across the mosaic genome of Sanjiang cattle showing an excess of taurine or indicine ancestry. Taurine ancestry might contribute to meat quality, and indicine ancestry is more conducive to adaptation to hot climate conditions, making Sanjiang cattle a valuable genetic resource for the central region of China. Our results will help us understand the evolutionary history and ancestry components of Sanjiang cattle, which will provide a reference for resource conservation and selective breeding of Chinese native cattle.

The devastating wheat stripe (yellow) rust pathogen, Puccinia striiformis f. sp. tritici (Pst), is a macrocyclic and heteroecious fungus. Pst produces urediniospores and teliospores on its primary host, wheat, and pycniospores and aeciospores are produced on its alternate hosts, barberry (Berberis spp.) or mahonia (Mahonia spp.). Basidiospores are developed from teliospores and infect alternate hosts. These five spore forms play distinct roles in Pst infection, disease development, and fungal survival, etc. However, the specific genes and mechanisms underlying these functional differences are largely unknown. In this study, we performed, for the first time in rust fungi, the deep RNA sequencing to examine the transcriptomic shift among all five Pst spore forms. Among a total of 29,591 identified transcripts, 951 were specifically expressed in basidiospores, whereas 920, 761, 266, and 110 were specific for teliospores, pycniospores, aeciospores, and urediniospores, respectively. Additionally, transcriptomes of sexual spores, namely pycniospores and basidiospores, showed significant differences from those of asexual spores (urediniospores, teliospores, and aeciospores), and transcriptomes of urediniospores and aeciospores were more similar to each other than to the three other spore forms. Especially, the basidiospores and pycniospores which infected the berberis shows wide differences in the cell wall degrading-enzymes and mating and pheromone response genes. Besides, we also found that there are 6234 differential expressed genes between the urediniospores and pycniospores, while only have 3 genes have alternative splicing enents, suggesting that differential genes expression may make more contribution than AS. This comprehensive transcriptome profiling can substantially improve our understanding of the developmental biology of the wheat stripe rust fungus.

DNA damage, which may arise from cellular activities or be induced by genotoxic stresses, can cause genome instability and significantly affect plant growth and productivity. In response to genotoxic stresses, plants activate the cellular DNA damage response (DDR) to sense the stresses and activate downstream processes. The transcription factor SUPPRESSOR OF GAMMA RESPONSE 1 (SOG1), a functional counterpart of mammalian p53, is a master regulator of the DDR in plants. It is activated by various types of DNA lesions and can activate the transcription of hundreds of genes to trigger downstream processes, including cell cycle arrest, DNA repair, endoreplication, and apoptosis. Since SOG1 plays a crucial role in DDR, the activity of SOG1 must be tightly regulated. A recent study published in Plant Cell (Chen et al., Plant Cell koad126, 2023) reports a novel mechanism by which the ATR-WEE1 kinase module promotes SOG1 translation to fine-tune replication stress response.

Phototropism is a classic adaptive growth response that helps plants to enhance light capture for photosynthesis. It was shown that hydrogen peroxide (H₂O₂) participates in the regulation of blue light-induced hypocotyl phototropism; however, the underlying mechanism is unclear. In this study, we demonstrate that the unilateral high-intensity blue light (HBL) could induce asymmetric distribution of H₂O₂ in cotton hypocotyls. Disruption of the HBL-induced asymmetric distribution of H₂O₂ by applying either H₂O₂ itself evenly on the hypocotyls or H₂O₂ scavengers on the lit side of hypocotyls could efficiently inhibit hypocotyl phototropic growth. Consistently, application of H₂O₂ on the shaded and lit sides of the hypocotyls led to reduced and enhanced hypocotyl phototropism, respectively. Further, we show that H₂O₂ inhibits hypocotyl elongation of cotton seedlings, thus supporting the repressive role of H₂O₂ in HBL-induced hypocotyl phototropism. Moreover, our results show that H₂O₂ interferes with HBL-induced asymmetric distribution of auxin in the cotton hypocotyls. Taken together, our study uncovers that H₂O₂ changes the asymmetric accumulation of auxin and inhibits hypocotyl cell elongation, thus mediating HBL-induced hypocotyl phototropism.

The thermotolerant yeast Kluyveromyces marxianus is known for its potential in high-temperature ethanol fermentation, yet it suffers from excess acetic acid production at elevated temperatures, which hinders ethanol production. To better understand how the yeast responds to acetic acid stress during high-temperature ethanol fermentation, this study investigated its transcriptomic changes under this condition. RNA sequencing (RNA-seq) was used to identify differentially expressed genes (DEGs) and enriched gene ontology (GO) terms and pathways under acetic acid stress. The results showed that 611 genes were differentially expressed, and GO and pathway enrichment analysis revealed that acetic acid stress promoted protein catabolism but repressed protein synthesis during high-temperature fermentation. Protein-protein interaction (PPI) networks were also constructed based on the interactions between proteins coded by the DEGs. Hub genes and key modules in the PPI networks were identified, providing insight into the mechanisms of this yeast's response to acetic acid stress. The findings suggest that the decrease in ethanol production is caused by the imbalance between protein catabolism and protein synthesis. Overall, this study provides valuable insights into the mechanisms of K. marxianus's response to acetic acid stress and highlights the importance of maintaining a proper balance between protein catabolism and protein synthesis for high-temperature ethanol fermentation.

Plants employ pattern- and effector-triggered immunity (PTI and ETI) to synergistically defend invading pathogens and insect herbivores. Both PTI and ETI can induce cytosolic Ca²⁺ spikes, despite in different spatiotemporal patterns, to activate downstream Ca²⁺-dependent immune signaling cascades. While multiple families of Ca²⁺-permeable channels at the plasma membrane have been uncovered, the counterparts responsible for Ca²⁺ release from intracellular stores remain poorly understood. In a groundbreaking paper published recently by Cell, the authors reported that WeiTsing, an Arabidopsis endoplasmic reticulum (ER)-resident protein that was specifically expressed in the pericycle upon Plasmodiophora brassicae (Pb) infection, could form resistosome-like Ca²⁺-conducting channel and protect the stele of Brassica crops from Pb colonization. As the channel activity of WeiTsing was indispensable for its immune function, the findings highlight a previously underappreciated role of Ca²⁺ release from intracellular repertoire in promoting plant disease resistance.