Plant, Cell & Environment最新文献

Plants can perceive specific elicitors in the oral secretions (OS) of herbivorous insects and respond by increasing their defences. Whether plants can discriminate among similar herbivorous insect species and differentially modulate their defence responses against them is largely unknown. Here, we investigated the responses of the maize transcriptome, phytohormones, and volatile emissions to the OS of three closely related Spodoptera caterpillars: the fall armyworm S. frugiperda, the beet armyworm S. exigua, and the cotton leafworm S. littoralis. Maize plants strongly increased their phytohormone levels and volatile emissions when treated with each of the OS, which was reflected in the transcription levels of genes involved in phytohormone signalling, and primary and secondary metabolism. Compared to the OS of S. exigua and S. littoralis, the secretion of the maize specialist S. frugiperda, elicited greater changes in the maize transcriptome but triggered considerably lower volatile emissions. Besides revealing the generality and specificity of maize responses to different lepidopteran caterpillars, the dataset provides a molecular resource for studies that aim to identify and characterise herbivore-specific elicitors and effectors and their receptors. This information can then be used to elucidate and possibly disrupt the mechanisms that allow well-adapted herbivorous insects to manipulate maize defences.

Nitrogen and phosphorus constitute essential elements that play pivotal roles in plant growth and development. Nevertheless, the molecular mechanisms that underpin the intricate cross-talk between nitrogen and phosphorus in maize have not been fully deciphered. In the present study, the phosphate transporter ZmPT7 gene was identified and isolated through a reverse genetic screening approach, specifically targeting mutants that exhibited sensitivity to low nitrate (NO₃ ^-). Subsequently, the functions of ZmPT7 were probed and analyzed in-depth using data-independent acquisition (DIA)-based quantitative proteomics, followed by a series of comprehensive validation experiments. It was revealed that, although ZmPT7 does not independently act as a NO₃ ^- transporter, it actively participates in an interaction with ZmNRT2.2. This interaction leads to the enhancement of the protein abundance of ZmNRT2.2, thereby effectively modulating NO₃ ^- uptake under conditions of limited NO₃ ^- availability. This significant discovery substantially contributes to the elucidation and clarification of the molecular mechanisms that govern the coordinated cross-talk between nitrogen and phosphorus in maize during its adaptation to NO₃ ^- deficiency. Consequently, it enriches our understanding of the survival strategies and adaptive mechanisms employed by this important crop species, providing valuable insights for further research and agricultural applications.

In natural environments, plants compete with neighbouring plants for resources such as light, water and nutrients. To detect neighbours, plants have evolved mechanisms that are poorly understood at the molecular-genetic level. This study examined the impact of competition on the growth and reproductive success of Arabidopsis thaliana grown in crowded settings together with conspecifics or with the grass Lolium perenne. Intraspecific and interspecific competition resulted in strongly reduced shoot branching and silique production. The reduction in shoot branching correlated with greatly altered gene expression in lateral buds, in particular of hormone- and defence-related genes, while it was independent of the hub transcription factor BRANCHED1. Mutants defective in strigolactone signalling retained a response to competition. Similarly, competitors unable to synthesize strigolactones caused a normal inhibitory effect, indicating that strigolactones are not required for a response of Arabidopsis to competition. Fertilization did not overcome the inhibitory effect of competition, showing that plants under competition did not experience a lack of mineral nutrients. When the roots of focal and competitor plants were separated by water-impermeable below-ground partitions, plants did not respond to competition. We suggest that below-ground communication, together with a sensing of soil volume, participates in the response to competition.

Teosinte (Zea mays subsp. mexicana) has been proposed as a potential source of biological nitrification inhibition (BNI), yet how nitrogen (N) inputs modulate its exudate chemistry and associated nitrification processes remains unclear. We compared teosinte with three maize cultivars under N-deficient and N-replete conditions, integrating non-targeted metabolomics of root exudates, qPCR of rhizosphere amoA genes, and pure-culture assays with Nitrosomonas europaea. N fertilisation enhanced total root exudation and reprogrammed the teosinte metabolome toward amino and phenolic acids, with histidine, glutamic acid, ferulic acid, and vanillic acid being markedly enriched. These compositional shifts coincided with reduced archaeal amoA abundance in teosinte (and Zhengdan958) but increased levels in Ye478 and Qi319. In culture, exudates from N-fed teosinte strongly inhibited N. europaea ammonia oxidation (~ 63%), whereas exudates from modern maize, except for Zhengdan958, showed little effect. Histidine, vanillic acid and ferulic acid reproduced inhibition in targeted assays, implicating them as candidate BNIs likely acting through copper chelation and phenolic interference. Collectively, these findings demonstrate that N availability reshapes teosinte exudate chemistry, thereby strengthening nitrification suppression through specific amino- and phenolic-acid release. Leveraging these wild traits could inform sustainable N management and enhance nitrogen-use efficiency in maize-based agroecosystems.

Anthocyanins and lignin, both derived from the phenylpropanoid pathway, play essential roles in plant defence and development. While anthocyanins attract pollinators and provide antioxidative protection under stress, lignin contributes to structural integrity, vascular function, and pathogen resistance. R2R3-MYB transcription factors are key regulators of these pathways, functioning as both activators and repressors. Here, we functionally characterised NtMYB308, a tobacco R2R3-MYB transcription factor containing a bHLH-interaction motif and an EAR repression domain. Virus-induced gene silencing (VIGS) and promoter-binding assays demonstrated that NtMYB308 acts as a transcriptional repressor of anthocyanin and lignin biosynthetic genes. CRISPR/Cas9-generated knockout lines (NtMYB308^CR) exhibited elevated anthocyanin accumulation and increased lignin deposition, whereas overexpression lines (NtMYB308OX) showed reduced levels of both metabolites. Notably, NtMYB308^CR plants displayed increased resistance towards fungal pathogens Alternaria solani and Rhizoctonia solani, likely due to reinforced cell walls and elevated antioxidant capacity. In contrast, NtMYB308OX plants were more susceptible. These findings establish NtMYB308 as a key negative regulator of phenylpropanoid metabolism and biotic stress tolerance, offering a potential target for genetic manipulation to enhance disease resistance and reduce reliance on chemical pesticides, thereby promoting sustainable crop production and environmental health.

Increasing evidences show plant growth-promoting rhizobacteria (PGPR) benefit legume-rhizobium symbiosis, and iron-based nanoparticles (FeNPs) act as rhizobia microenvironment stabilizers. However, few studies explored if their combination exerts synergistic effects on the symbiosis in legume. Here, we compared the effects of FeNPs, Pseudomonas rhizovicinus M30-35, and their co-application (Fe + M) on alfalfa growth, nitrogen fixation, root metabolites, and rhizosphere microbiome. Compared with FeNPs and M30-35, Fe + M increased shoot height, root length, root activity, chlorophyll content, and net photosynthetic rate (Pn) by 63.2% and 45.4%, 61.1% and 70.6%, 56.2% and 47.1%, 20.1% and 18.6%, and 41.1% and 30.6%, respectively; the nodule number, nitrogenase activity, ureide content, and leghemoglobin content rose by 29.6% and 31.4%, 58.5% and 78.7%, 20.4% and 15.1%, and 9.7% and 12.4%, respectively. Metabolomic analysis showed that Fe + M enhanced the accumulation of benzenoid compounds in roots, while microbial co-occurrence network analysis indicated reduced complexity and connectivity of rhizosphere bacterial and fungal communities. Importantly, core microbes, such as Hydrogenophaga, Nocardioides, unidentified_Mitochondria, and Scedosporium, were positively associated with benzenoid compounds, which contribute to nutrient cycling in the rhizosphere. Our findings demonstrate that FeNPs and PGPR strain together achieve synergistic effects on the nitrogen fixation in alfalfa.