The efficient infection of plants by the bacteria Xanthomonas campestris pv. campestris (Xcc) depends on its type III effectors (T3Es). Although the functions of AvrE-family T3Es have been reported in some bacteria, the member (XopAM) in Xcc has not been studied. As XopAM has low sequence similarity to reported AvrE-T3Es, and different reports have shown that these T3Es have different targets in hosts, we investigated the functions of XopAM in the Xcc-plant interaction. Deletion of xopAM from Xcc reduced its virulence in cruciferous crops but increased virulence in Arabidopsis (Arabidopsis thaliana) Col-0, indicating that XopAM may perform opposite functions depending on the host species. We further found that XopAM is a lipase that may target the cytomembrane and that this activity might be enhanced by its membrane-targeted protein XOPAM-ACTIVATED RESISTANCE 1 (AMAR1) in Arabidopsis Col-0. The binding of XopAM to AMAR1 induced an intense hypersensitive response that restricted Xcc proliferation. Our results showed that the roles of XopAM in Xcc infection are not the same as those of other AvrE-T3Es, indicating that the functions of this type of T3E have differentiated during long-term bacterium‒host interactions.

Agrobacterium tumefaciens can cause crown gall tumors by transferring both an oncogenic piece of DNA (T-DNA) and several effector proteins into a wide range of host plants. For the translocated effector VirE3 multiple functions have been reported. It acts as a transcription factor in the nucleus binding to the Arabidopsis thaliana pBrp TFIIB-like protein to activate the expression of VBF, an F-box protein involved in degradation of the VirE2 and VIP1 proteins, facilitating Agrobacterium-mediated transformation. Also VirE3 has been found at the plasma membrane, where it could interact with VirE2. Here, we identified AtJAZ8 in a yeast two-hybrid screening with VirE3 as a bait and confirmed the interaction by pull-down and bimolecular fluorescence complementation assays. We also found that the deletion of virE3 reduced Agrobacterium virulence in a root tumor assay. Overexpression of virE3 in Arabidopsis enhanced tumorigenesis, whereas overexpression of AtJAZ8 in Arabidopsis significantly decreased the numbers of tumors formed. Further experiments demonstrated that AtJAZ8 inhibited the activity of VirE3 as a plant transcriptional regulator, and overexpression of AtJAZ8 in Arabidopsis activated AtPR1 gene expression while it repressed the expression of AtPDF1.2. Conversely, overexpression of virE3 in Arabidopsis suppressed the expression of AtPR1 whereas activated the expression of AtPDF1.2. Our results proposed a novel mechanism of counter defense signaling pathways used by Agrobacterium, suggesting that VirE3 and JAZ8 may antagonistically modulate the salicylic acid/jasmonic acid (SA/JA)-mediated plant defense signaling response during Agrobacterium infection.

Penicillium griseofulvum CF3 is a fungus isolated from healthy strawberry soil, with the potential to promote the growth of plants and enhance their resistance to diseases. However, the genome sequence of P. griseofulvum CF3 remains unclear. Therefore, we performed the whole-genome CCS sequencing of P. griseofulvum CF3 using the PacBio Sequel II platform. The assembled genome comprised 104 contigs, with a total length of 37,564,657 bp, encoding 13,252 protein-coding genes. Comprehensive functional annotation was performed using various BLAST databases, including the non-redundant (Nr) protein sequence database, Gene Ontology (GO), the Kyoto Encyclopedia of Genes and Genomes (KEGG), EuKaryotic Orthologous Groups (KOG), and the Carbohydrate-Active enZymes (CAZy) database, to identify and predict protein-coding genes, tRNAs, and rRNAs. The Antibiotics and Secondary Metabolites Analysis Shell (Antismash) analysis identified 50 biosynthetic gene clusters involved in secondary metabolite production within the P. griseofulvum CF3 genome. The whole-genome sequencing of P. griseofulvum CF3 helps us to understand its potential mechanisms in promoting plant growth and enhancing disease resistance, paving the way for the application of the CF3 strain in sustainable crop production.

Receptor-like cytoplasmic kinases (RLCKs), which belong to a large subgroup of receptor-like kinases in plants, play crucial roles in plant development and immunity. However, their functions and regulatory mechanisms in plants remain unclear. Here, we report functional characterization of OsRLCK118 from the OsRLCK34 subgroup in rice (Oryza sativa L.). Expression of OsRLCK118 could be induced by infections with Xanthomonas oryzae pv. oryzae (Xoo) strains PXO68 and PXO99. Silencing of OsRLCK118 altered plant height, flag-leaf angle and second-top-leaf angle. Silencing of OsRLCK118 also resulted in increasing susceptibility to Xoo and Magnaporthe oryzae (M. oryzae) in rice plants. OsRLCK118 knock-out plants were more sensitive to bacterial blight whereas OsRLCK118 overexpressor plants exhibited increased disease resistance. Expression levels of pathogenesis-related genes of OsPAL1, OsNH1, OsICS1, OsPR1a, OsPR5 and OsPR10 were reduced in the rlck118 mutant compared to wild-type rice (Dongjin) and knock-out of OsRLCK118 compromised the production of reactive oxygen species. These results suggest that OsRLCK118 may modulate basal resistance to Xoo and M. oryzae, possibly through regulation of ROS burst and hormone mediated defense signaling pathway.

This study aimed to determine the effects of different dosages of an organic amendment, consisting of a Chinese herbal compound, on cassava growth and rhizosphere microbial diversity. In this study, cassava SC8 growth was determined under four treatments. The growth was promoted with the application of an organic herbal compound amendment, biochar powder, and an agent, in the following groups: 900 kg/ha of organic amendment powder (topdressing) + agent (T1); 1200 kg/ha of organic amendment powder (topdressing) + agent (T2); 1500 kg/ha of organic amendment powder (topdressing) + agent (T3); and an unfertilized control (T4). After 240 days of treatment, the height, the diameter of the stem, the maximum perimeter of the cassava, the tuber number, the weight of a single tuber, the yield per hectare, the mineral elements in the cassava plant, the ash content in the starch and the microbial diversity in the soil were measured. Compared with the control group, the application of 1200 kg of the Chinese herbal compound amendment per ha (T2) had the strongest positive effect on cassava growth, while the height, diameter of the stem and yield per hectare all showed increases of 24.22%, 18.82% and 35.71%, respectively. As for the dry matter content of the tubers, that of T2 decreased by 5.96% compared with T4, while no substantial difference existed among the other groups. The Fe content in T2 decreased by 29.46%, and the Zn in T3 increased by 39.48%, while the contents of other metal ions in the four treatment groups showed no substantial difference. At the same time, the experiment also revealed that, in terms of the bacterial abundance in the soil, Streptophyta dominated in T2, and Fimbriimonas was the unique genera of T2. In addition, the abundances of Nocardioides and unclassfied_Spartobacteria in the T2 group were greatly considerable compared to the other treatment groups. In terms of the fungal abundance in the soil, after being treated with different concentrations, the composition of the soil’s fungi differed greatly among the groups, and the samples at different concentrations contained more than 20 species of unique bacteria. At the genus level, compared with the control group, the relative abundance of unclassfied_Chaetomiaceae in the treatment groups was considerably reduced, and the relative abundance of Psathyrella in T1 increased substantially. The results indicated that the organic amendment could improve the growth of cassava, as well as help to enhance the diversity and optimize the composition of the rhizosphere microbiome.

Soil salinization threatens global agriculture, reducing crop productivity and food security. Developing strategies to improve salt tolerance is crucial for sustainable agriculture. This study examines the role of organic fertilizer in mitigating salt stress in rice (Oryza sativa L.) by integrating NDVI and metabolomics. Using salt-sensitive (19X) and salt-tolerant (HHZ) cultivars, we aimed to (1) evaluate changes in NDVI and metabolite content under salt stress, (2) assess the regulatory effects of organic fertilizer, and (3) identify key metabolites involved in stress response and fertilizer-induced regulation. Under salt stress, survival rate of the 19X plants dropped to 6%, while HHZ maintained 38%, with organic fertilizer increasing survival rate to 25% in 19X and 66% in HHZ. NDVI values declined sharply in 19X (from 0.56 to <0.25) but remained stable in HHZ (~0.56), showing a strong correlation with survival rate (R² = 0.87, p < 0.01). NDVI provided a dynamic, non-destructive assessment of rice health, offering a faster and more precise evaluation of salt tolerance than survival rate analysis. Metabolomic analysis identified 12 key salt-tolerant metabolites, including citric acid, which is well recognized for regulating salt tolerance. HTPA, pipecolic acid, maleamic acid, and myristoleic acid have previously been reported but require further study. Additionally, seven novel salt-tolerant metabolites—tridecylic acid, propentofylline, octadeca penten-3-one, 14,16-dihydroxy-benzoxacyclotetradecine-dione, cyclopentadecanolide, HpODE, and (±)8,9-DiHETE—were discovered, warranting further investigation. Organic fertilizer alleviated salt stress through distinct metabolic mechanisms in each cultivar. In 19X, it enhanced antioxidant defenses and energy metabolism, mitigating oxidative damage and improving fatty acid metabolism. In contrast, HHZ primarily benefitted from improved membrane stability and ion homeostasis, reducing lipid peroxidation and oxidative stress. These findings primarily support the identification and screening of salt-tolerant rice cultivars while also highlighting the need for cultivar-specific fertilization strategies to optimize stress resilience and crop performance. Based on the correlation analysis, 26 out of 53 differential metabolites were significantly correlated with NDVI, confirming a strong association between NDVI shifts and key metabolic changes in response to salt stress and organic fertilizer application. By integrating NDVI and metabolomics, this study provides a refined method for evaluating salt stress responses, capturing early NDVI changes and key salinity stress biomarkers. This approach may prove valuable for application in salt-tolerant variety screening, precision agriculture, and sustainable farming, contributing to scientific strategies for future crop improvement and agricultural resilience.