生命科学最新文献

β-Alanine, an abundant non-proteinogenic amino acid, acts as a precursor for coenzyme A and plays a role in various stress responses. However, a comprehensive understanding of its metabolism in plants remains incomplete. Previous metabolic genome-wide association studies (mGWAS) identified ALANINE:GLYOXYLATE AMINOTRANSFERASE2 (AGT2, AT4G39660) linked to β-alanine levels in Arabidopsis under normal conditions. In this study, we aimed to deepen our insights into β-alanine regulation by conducting mGWAS under two contrasting environmental conditions: control (12 h photoperiod, 21°C, 150 μmol m⁻² sec⁻¹) and stress (harvested after 1820 min at 32°C and darkness). We identified two highly significant quantitative trait loci (QTL) for β-alanine, including the AGT2 locus associated in both environments and ALDEHYDE DEHYDROGENASE6B2 (ALDH6B2, AT2G14170) associated only under stress conditions. A coexpression-correlation network revealed that the regulatory pathway involving β-alanine levels, AGT2, and ALDH6B2 connects the branched chained amino acid (BCAA) degradation through the propionate pathway. Metabolic profiles of AGT2 overexpression (OE) and knock-out (KO) lines (agt2) across various organs and developmental stages established the critical role of AGT2 in β-alanine metabolism. This work underscores the importance of β-alanine homeostasis for proper growth and development in Arabidopsis.

Nucleotide-binding leucine-rich repeat (NLR) genes play a critical role in plant effector-triggered immunity (ETI) against pathogen invasion. However, the regulatory mechanisms governing NLR expression and functional dynamics, particularly in head-to-head NLR gene pairs, remain poorly understood. In this study, we investigated the regulatory mechanisms, subcellular localization and functional pathways associated with Pik-H4 gene pair. Bidirectional Pik-H4 promoter (P_Pik-H4) strengths were found across the whole plants and exhibited co-expressed patterns in tissues and cells, and the P_Pik-H4 activity was upregulated in vascular bundles during blast fungus invasion. Additionally, altering the co-expression of Pik₁-H4 and Pik₂-H4 via overexpression in rice or Nicotiana benthamiana did not compromise the immune response. Promoter analysis identified two minimal promoter regions that are essential for bidirectional transcription, and mutagenesis of the bidirectional TATA box confirmed its role in gene regulation. This dual-function promoter coordinates Pik-H4 expression in both directions, a regulatory innovation previously unreported in NLR-mediated immunity. In planta subcellular localization revealed Pik₁-H4 relocates to vesicles, indicating its role in effector recognition, while Pik₂-H4 predominantly accumulated in the nucleus. These new discoveries of Pik protein extended the putative immune function of NLR pairs. Transcriptome analysis demonstrated that Pik-H4-mediated resistance induces significant transcriptome reprogramming between 12- and 24-h postinoculation. In summary, these findings provide novel insights into the regulatory complexity and functional divergence within NLR bidirectional gene pairs in response to pathogen invasion.

Moving in a crowded cellular environment, proteins have to recognize and bind to each other with high specificity. This specificity reflects in a combination of geometric and chemical complementarities at the core of interacting regions that ultimately influences binding stability. Exploiting such peculiar complementarity patterns, we recently developed CIRNet, a neural network architecture capable of identifying pairs of protein core interacting residues and assisting docking algorithms by rescaling the proposed poses. Here, we present a detailed analysis of the geometric and chemical descriptors utilized by CIRNet, investigating its decision-making process to gain deeper insights into the interactions governing protein-protein binding and their interdependence. Specifically, we quantitatively assess (i) the relative importance of chemical and physical features in network training and (ii) their interplay at protein interfaces. We show that shape and hydrophobic-hydrophilic complementarities contain the most predictive information about the classification outcome. Electrostatic complementarity alone does not achieve high classification accuracy but is required to boost learning. Ultimately, our findings suggest that identifying the most information-dense features may enhance our understanding of the mechanisms driving protein-protein interactions at core interfaces.

Understanding plant heat tolerance requires assessing their thermal thresholds, but commonly used methods have rarely been compared. Moreover, whether the photosynthetic machinery is irreversibly damaged past these thresholds remains unclear. We determined the critical temperature (T_crit), the temperature causing a 50% reduction (T₅₀), and the maximum tolerable temperature (T_max) of photosystem II in Mediterranean cypress, Aleppo pine, and Scots pine saplings using 15- or 30-min heat exposure curves performed on living plants (in-vivo), excised needles (ex-vivo), and excised needles continuously exposed to each rising temperature (ex-vivo continuous). Dark-adapted fluorescence (F_v/F_m) and gas exchange were recorded for 4 days postheat stress to track recovery. Longer heat exposure (30 vs. 15 min) consistently led to lower F_v/F_m, T₅₀, and T_max. T₅₀ and T_max were reduced in both ex-vivo conditions compared to in-vivo ones. Conversely, T_crit remained consistent between species, exposure durations, and methods. Gas exchange and F_v/F_m recovery mainly occurred before reaching T₅₀ values (about 45°C). Our work highlights the importance of exposure duration and method selection when measuring and comparing thermal thresholds. Moreover, while T_crit appears to be a reversible threshold, the photosynthetic machinery of studied species appears irreparably damaged past their T50.

Germination represents the first major transition in plants, and seed dormancy influences germination timing. However, the mechanism by which variations in seed dormancy due to genetic variation or the maternal environment influence germination timing has not been studied in depth. In this study, the effects of temperature during seed maturation (maternal temperature) and genetic variation on weedy rice seedling emergence in a field environment were evaluated. The experiments were repeated for 4 years using seeds collected from weedy rice groups, which represented different degrees of seed dormancy. The maternal temperature was evaluated via the yearly variation in the field temperature. Genetic variation had a greater effect on seedling emergence during unfavourable seasons than during favourable seasons. A higher maternal temperature delayed seedling emergence during favourable seasons. The notable impact of global warming on seedling emergence has been confirmed over the past 15 years, and this impact will continue even under the sustainable CO₂ emission scenario. Maternal effects have long-term effects on seedling emergence at relatively high maternal temperatures, and these effects may increase under global warming.

Outside Front Cover: The cover image is based on the article Crucial Role of Aluminium-Regulated Flavonol Glycosides (F2-Type) Biosynthesis in Lateral Root Formation of Camellia sinensis by Sanyan Lai et al., https://doi.org/10.1111/pce.15372.

Terrestrial plants naturally produce chemical signals to attract beneficial insects or repel harmful pests. These inherent plant attributes offer promising opportunities for eco-friendly pest control in agriculture, particularly through the push-pull intercropping technique. However, our understanding of potential repellent plants and their effective chemical signals remains limited. In this study, we evaluated multiple plant species for their repellent properties, identified effective volatile organic compounds, and investigated the mechanisms for controlling the fungus gnat Bradysia odoriphaga in Chinese chives. Among the 12 species tested, Mentha haplocalyx, Ocimum basilicum and Pelargonium graveolens demonstrated strong repellent effects, making them promising candidates as 'push' plants. Eight major volatile compounds were identified as effective repellents, with 1,8-cineole being the most efficient. 1,8-cineole consistently exhibited repellent effects against the fungus gnats across various concentrations and exposure durations. Transcriptomic analysis revealed that exposure to 1,8-cineole upregulated genes is associated with energy production processes, suggesting that the fungus gnats can detect and actively avoid this compound. Field experiments further confirmed the effectiveness of this strategy, as intercropping chives with M. haplocalyx significantly reduced fungus gnat infestations. This study presents a novel intercropping approach for managing fungus gnats and offers valuable insights into sustainable eco-friendly pest management practices in agriculture.

The presence of toxic heavy metals lead (Pb) and cadmium (Cd) in polluted soil damage crop production and consequently harms human and livestock health. Tartary buckwheat (Fagopyrum tataricum) is a potential model plant for heavy metal phytoremediation because of its valuable characteristics of high heavy metal tolerance and abundant biomass production. Here, we report that the Tartary buckwheat FtMYB46-FtNRAMP3 module enhances plant Pb and Cd tolerance. RNA sequencing analysis showed that Pb treatment specifically induced expression of FtNRAMP3, a member of the NRAMP (Natural Resistance-Associated Macrophage Protein) transporter gene family. Further cytological and biochemical analysis revealed that FtNRAMP3 was localised to the plasma membrane and significantly contributed to increased tolerance to Pb and Cd in yeast cells. Consistently, transgenic overexpression of FtNRAMP3 in Arabidopsis significantly increased plant tolerance to Pb and Cd applications, reducing Pb concentration but increasing Cd concentration in the overexpression transgenic plants. Subsequent yeast one-hybrid and electrophoretic mobility shift assays showed that the transcription factor FtMYB46 directly binds to the FtNRAMP3 promoter. Further, FtMYB46 promoted FtNRAMP3 expression and increased plant Pb and Cd tolerance. Overall, this study demonstrates the important role of the FtMYB46-FtNRAMP3 module and its potential value in the phytoremediation of Pb and Cd stress.

Salt stress can seriously affect plant survival. To adapt to salt stress, plants can alter gene expressions and/or pre-mRNA processing patterns, or both. Previous studies could not comprehensively profile stress-responsive pre-mRNA processing patterns due to limitations in traditional sequencing technologies. Now Oxford Nanopore Technologies Direct RNA Sequencing (ONT DRS) can directly sequence full-length native RNAs without requiring reverse transcription or amplification. Thus, it provides accurate profiles of pre-mRNA processing patterns at the single-molecule level. With this technology, we found more than 89 586 novel transcript isoforms in addition to the 44 877 annotated ones in soybean leaves and roots subjected to short-term salt stress. Specifically, we identified 102 191 alternative mRNA processing events and 1216 fusion transcripts corresponding to 549 genomic regions. Interestingly, genes upregulated in roots due to salt stress had longer poly(A) tail lengths and lower m6A modification ratios than controls, and downregulated genes in roots had shorter poly(A) tails. Also, the m6A modification levels changed with prolonged salt stress. Furthermore, the alteration patterns of m6A modifications under salt stress were correlated with the expressions of two m6A erasers. Our results indicated that the reshaped mRNA traits caused by salt stress could play a role in soybean adaptations.