Plant signaling & behavior最新文献

Strigolactones (SLs) are signaling compounds made by plants. They play a crucial role in acting as long-distance signals from root to shoot to coordinate shoot growth with root environmental conditions. Here, we test whether and how SLs play a role in the climbing behavior of pea plants by studying the circumnutation of the tendrils using three-dimensional (3D) kinematical analysis. To assess this, we compare the typical behavior of P. sativum, a wild-type plant that produces and perceives SLs, with mutants defective in SLs synthesis or signaling, known as ramosus(rms) mutants. The results indicate that mutant plants seem unable to locate and grasp a potential support. Their movement appears to be disoriented and much less energized. We contend that this research opens new avenues for exploring SLs' role in plant behavior, a novel lens through which the role of SLs in root-to-shoot communication can be observed and analyzed.

Tobacco is a significant economic crop cultivated in various regions of China. Arbuscular mycorrhizal fungi (AMF) can establish a symbiotic relationship with tobacco and regulate its growth. However, the influences of indigenous AMF on the growth and development of tobacco and their symbiotic mechanisms remain unclear. In this study, a pot inoculation experiment was conducted, revealing that six inoculants - Acaulospora bireticulata(Ab), Septoglomus viscosum(Sv), Funneliformis mosseae(Fm), Claroideoglomus etunicatum(Ce), Rhizophagus intraradices(Ri), and the mixed inoculant (H) - all formed stable symbiotic relationships with tobacco. These inoculants were found to enhance the activities of SOD, POD, PPO, and PAL in tobacco leaves, increase chlorophyll content, IAA content， CTK content， soluble sugars, and proline levels while reducing malondialdehyde content. Notably, among these inoculants, Fm exhibited significantly higher mycorrhizal infection density, arbuscular abundance, and soil spore density in the root systems of tobacco plants compared to other treatments. Membership function analysis confirmed that Fm had the most pronounced growth-promoting effect on tobacco. The transcriptome analysis results of different treatments of CK and inoculation with Fm revealed that 3,903 genes were upregulated and 4,196 genes were downregulated in the roots and stems of tobacco. Enrichment analysis indicated that the majority of these genes were annotated in related pathways such as biological processes, molecular functions, and metabolism. Furthermore, differentially expressed genes associated with auxin, cytokinin, antioxidant enzymes, and carotenoids were significantly enriched in their respective pathways, potentially indirectly influencing the regulation of tobacco plant growth. This study provides a theoretical foundation for the development and application of AMF inoculants to enhance tobacco growth.

The longevity of the rose stem is often affected by the rate of respiration and the evolution in ethylene production, which also favors the development of Botrytis. Silicon is involved in plant defense, and its application could be a strategy to improve disease control. This research evaluated the effect of foliar and edaphic applications of silicon on the life of the Brighton rose using three sources of liquid silicon applied every 2 weeks in three foliar and edaphic conditions and one control. After harvest, the fresh mass loss, ethylene concentration, O₂ consumption and CO₂ evolution were measured. The number of fallen petals was counted, and the severity of the Botrytis infection was evaluated. The biomass loss of the floral stem was analyzed with profile analysis. For the evaluation of the change in values of O₂, CO₂ and ethylene, a multivariate semiparametric analysis of variance analysis was used and the generalized estimating equation methodology for the longitudinal binary response of severity. It was found that the soil treatment with lower potassium and soluble silicon was associated with a decrease in ethylene concentration as well as also turned out to be the one that best controlled Botrytis in post-harvest.

Polygonatum sibiricum Red, known as Huangjing in Chinese, is a perennial plant valued in traditional Chinese medicine and is a nutritional food ingredient. With increasing market demand outpacing wild resource availability, cultivation has become essential for sustainable production. However, the cultivation of P. sibiricum is challenged by the double dormancy characteristics of seeds, which include embryo and physiological dormancy. This affected the germination of seeds and the establishment of seedlings. This study investigates the role of plant hormones in breaking seed dormancy and regulating germination and emergence in P. sibiricum. We found that cold stratification at 4°C for over 70 d significantly alleviates seed dormancy, associated with changes in endogenous hormone levels. Auxin, gibberellin, abscisic acid, cytokinin, salicylic acid, jasmonic acid, and ethylene were identified as key players in these processes. Exogenous applications of GA3 and 2-coumarate (2-hydroxycinnamic acid) significantly enhanced seed germination, while 6-BA and GA3 promoted corm growth and development. In conclusion, our research provides insights into the hormonal regulation of seed dormancy and germination in P. sibiricum, offering valuable strategies for improving cultivation practices. Further studies are needed to explore the specific mechanisms of hormone interactions and to develop optimized germination and seedling establishment strategies for this medicinally important plant.

Tobacco (Nicotiana tabacum) black shank disease, caused by Phytophthora nicotianae, is a significant threat to tobacco crops, leading to severe economic losses. Prolonged use of agrochemicals to control this disease has prompted the exploration of eco-friendly biological control strategies. This study investigated the effects of Trichoderma harzianum, a biocontrol agent, on N. tabacum in comparison to P. nicotianae, focusing on growth, biomass, root morphology and anatomy, hormonal changes, and osmotic regulation. T. harzianum significantly enhanced plant growth, biomass accumulation, root system development, and physiological attributes such as photosynthetic pigment levels and antioxidant enzyme activity. In contrast, P. nicotianae negatively impacted these parameters, inhibiting growth and physiological function. Notably, T. harzianum increased proline content and enhanced induced resistance mechanisms, mitigating stress and promoting overall plant health. These findings highlight the potential of T. harzianum as a sustainable solution for managing black shank disease while improving tobacco crop productivity.

Reproducibility in organ size and shape is a fascinating trait of living organisms. The mechanisms underlying such robustness remain, however, to be elucidated. Taking the sepal of Arabidopsis as a model, we investigated whether variability of gene expression plays a role in variation of organ size and shape. Previous work from our team identified cell-wall related genes as being enriched among the genes whose expression is highly variable. We then hypothesized that the variation of measured morphological parameters in cell-wall related single knockout mutants could be correlated with the variation in gene expression of the corresponding gene (the knocked-out gene) in wild-type plants. We analyzed sepal size and shape from 16 cell-wall mutants and found that sepal size variability correlates positively, not with gene expression variation, but with mean gene expression of the corresponding gene in wild type. These findings support a contribution of cell-wall related genes to the robustness of sepal size.

The most damaging disease affecting citrus globally is Huanglongbing (HLB), primarily attributed to the infection by 'Candidatus Liberibacter asiaticus' (CaLas). Based on comparative transcriptome data, two cellulose synthase (CESA) genes responsive to CaLas infection induction were screened, and one gene cloned with higher differential expression level was selected and named CsCESA1. we verified the interaction between CsCESA1 and citrus exopolysaccharide 2 (CsEPS2) proteins. Subcellular localization in tobacco indicated that both CsCESA1 and CsEPS2 proteins are primarily located in the nucleus and cytoplasm. RT-qPCR analysis indicated that the expression levels of CsCESA1 and CsEPS2 were associated with variety tolerance, tissue site, and symptom development. Furthermore, we generated CsCESA1 and CsEPS2 silencing plants and obtained CsCESA1 and CsEPS2 silencing and overexpressing hairy roots. The analysis of hormone content and gene expression also showed that CsCESA1 and CsEPS2 are involved in transcriptional regulation of genes involved in systemic acquired resistance (SAR) response. In conclusion, our results suggested that CsCESA1 and CsEPS2 could serve as potential resistance genes for HLB disease, offering insights into the plant's defense mechanisms against HLB.

Phosphatidic acid (PA) functions as a cell membrane component and signaling molecule in plants. PA metabolism has multiple routes, in one of which PA is converted into cytidine diphosphate diacylglycerol (CDP-DAG) by CDP-DAG synthases (CDSs). CDS genes are highly conserved in plants. Here, we found that knock-down of the CDS gene enhanced the resistance of Arabidopsis thaliana to multiple pathogens, with a growth penalty. When Arabidopsis leaves were treated with chitin or flg22, reactive oxygen species (ROS) production in cds mutants was significantly higher than that in the wild-type (WT). Similarly, phosphorylation of mitogen-activated protein kinases (MAPKs) in the cds1cds2 double mutant was significantly increased compared to the WT. By integrating lipidomics, transcriptomics, and metabolomics data, PA accumulation was observed in mutants cds1cds2, activating the jasmonic acid (JA) and salicylic acid (SA) signaling pathway, and increasing transcript levels of plant defense-related genes. Significant accumulation of the downstream metabolites including serotonin and 5-methoxyindole was also found, which plays important roles in plant immunity. In conclusion, our study indicated the role of CDSs in broad-spectrum disease resistance in Arabidopsis and that CDSs are involved in plant metabolic regulation.

Abscisic acid (ABA) mediated stomatal closure is a highly effective mode of active stomatal regulation under drought stress. Previous studies on stomatal regulation have primarily focused on the leaves of vascular plants, while research on the stomatal behavior of bulbous plants remains unknown. In addition, ABA-induced stomatal regulation in bulbs has yet to be explored. Therefore, we aim to investigate the ABA-induced active regulation in the bulb of the Lanzhou lily (Lilium davidii var. unicolor). The morphological characteristics of epidermal strips were analyzed along with a stomatal aperture assay to investigate the bulb's stomatal response to ABA. Moreover, the mechanism of ABA signaling was explored using treatments with ABA signaling chemicals and corresponding scavengers. This study revealed that stomata are mainly distributed on the upper part and outer surface of the bulb. The guard cells of the lily bulb are inflated, and the stomata have a nearly circular shape with relatively low stomatal density. Exogenous ABA was found to induce varying degrees of stomatal closure in a dose-dependent manner, with significant stomatal aperture reduction observed after treatment with 10 µM ABA. Overall, the study indicated that both hydrogen peroxide (H₂O₂) and nitric oxide (NO) are involved in the ABA-induced stomatal closure process, with H₂O₂ functioning as an upstream component of NO.

Fungal endophytes were recovered from Tamarix nilotica (Tamaricaceae) roots and stems collected in Taif, Saudi Arabia. A total of 49 different taxa were identified. The overall colonization rate of root and stem segments was 30.6%. A total of 49 isolates were collected and categorized into 21 operational taxonomic units using the rRNA gene's internal transcribed spacer region. The most prevalent species were Penicillium chrysogenum (16 isolates), Fungal sp. (12), and Alternaria alternata (10). Forty-nine isolates were investigated for antifungal activity against Fusarium solani and Rhizoctonia solani; all tested isolates showed antifungal activity against Fusarium solani, while 43 isolates showed antifungal activity against Rhizoctonia solani. The most potent antifungal agents against Fusarium solani and Rhizoctonia solani are Aspergillus ochraceus (2 isolates) and Penicillium chrysogenum (16 isolates). Endophytic isolates collected during this experiment were evaluated to produce amylase, cellulase, lipase, and protease enzymes. Among the strains examined for enzymatic potentials (4 enzymes), 26 strains (53% of the total strains) produce only one enzyme. Penicillium chrysogenum (TUPc2, 3, and 4) produced the highest amount of the four enzymes that were examined.