Publications

4859

ABSTRACT Citrus Huanglongbing (HLB), caused by ‘ Candidatus Liberibacter asiaticus’ ( Ca Las), is the most devastating disease affecting the global citrus industry. Here, we reported that the Ca Las effector SDE70 promotes HLB pathogenicity by targeting the citrus ubiquitination pathway. Transgenic expression of SDE70 in Wanjincheng orange ( Citrus sinensis Osbeck) accelerated early Ca Las proliferation, aggravated HLB symptoms, and increased susceptibility to citrus canker induced by Xanthomonas citri subsp. citri ( Xcc ). These results demonstrate that SDE70 functions as a broad‐spectrum suppressor of citrus immunity. Mechanistically, SDE70 physically interacts with CsRUB2, a citrus ubiquitin‐related protein. Furthermore, CsRUB2 overexpression in Wanjincheng oranges reduced resistance to HLB but enhanced resistance to citrus canker. Both SDE70 and CsRUB2 elevated salicylic acid (SA) and hydrogen peroxide (H 2 O 2 ) levels in transgenic plants while lowering methyl salicylate (MeSA) levels. CsRUB2 also decreased jasmonic acid (JA). In contrast to the suppressive effect of SDE70, CsRUB2 enhanced the transcription of citrus immunity genes. Transient expression assays further demonstrated that the SDE70–CsRUB2 interaction dysregulates citrus immunity by perturbing SA, MeSA, JA, and H 2 O 2 signals. These findings provide a theoretical basis for understanding citrus– Ca Las interactions and breeding citrus varieties with broad‐spectrum resistance to both HLB and citrus canker.

Persian lime (Citrus latifolia Tan.) is a crop of high economic and social relevance in Mexico due to its nutritional properties, associated health benefits, and particularly the foreign exchange generated through exportation. In recent years, the state of Veracruz has become the leading production region for this species at the national level. However, this crop is susceptible to several vascular diseases that cause significant economic losses in the citrus industry. Among these, Huanglongbing (HLB) is considered the most destructive disease, exerting the greatest impact on Persian lime production. This study involved the collection of Persian lime leaf tissues from different sources: field-grown plants, certified nursery plants, and plants previously sanitized through micrografting and thermotherapy processes. Genomic DNA was extracted from the collected samples. DNA integrity was verified by agarose gel electrophoresis and quantified using a NanoDrop One-C spectrophotometer. Quantitative Real-Time Polymerase PCR (qPCR) was performed using a QuantStudio One thermocycler and SYBR Green Master Mix as the fluorescent detection system. Samples were considered HLB-positive when the cycle threshold (Ct) value was below 35 during the quantification of Candidatus Liberibacter asiaticus. The results support the early, precise, and efficient detection of CLas by qPCR in Persian lime plants, thereby contributing to improved diagnostic and phytosanitary management strategies for this crop.

Strain IMCC14736, isolated from Korean coastal seawater by dilution-to-extinction culturing, represents a novel member of the OM43 clade within Methylophilaceae. The complete genome consists of a single contig of 1,286,469 bp with a DNA G + C content of 34.3% and encodes 1,358 predicted proteins. Genomic analysis revealed lanthanide-dependent methanol dehydrogenase genes and related C1 metabolism pathways. Based on phylogenetic evidence, the authors propose the name "Candidatus Methylolitoribacter marinus" for this strain.

Abstract Deception Island fumaroles in Antarctica represent rare environments where extreme heat intersects with cryospheric and marine conditions, creating remarkable environmental gradients. From the near-boiling sediments, we reconstructed a high-quality metagenome-assembled genome (MAG) affiliated with the Pyrodictiaceae. Phylogenomic analyses revealed that this genome, proposed to represent Ca. Pyroantarcticum pellizari, forms a distinct lineage separated from known genera in the family. Functional annotation uncovered a versatile metabolic repertoire, including pathways for sulfur and nitrogen cycling, peptide and amino acid transport, and mixotrophic energy conservation. Stress-response systems such as reverse gyrase, thermosome, and small heat-shock proteins were complemented by lineage-specific genes related to membrane stability, metal detoxification, and Pyrodictiaceae-specific cannulae. These adaptations likely support survival under sharp temperature gradients, hydrogen sulfide emissions, and high metal concentrations at the volcanic–cryosphere–marine interface. Our findings expand the phylogenetic and ecological scope of Pyrodictiaceae, highlighting Antarctic marine volcanoes as unique refuges for hyperthermophiles and as valuable models for investigating life’s habitability under extreme temperatures.