Transcriptomic study of Suaeda salsa in response to salt and drought stress
Zhijie Ding, Zhiyou Liu, Jinbo Bao, Yuwei Wang, Jialei Li, Qiuyan Wang, Xinmin Tian - Volume 50(10)
Gibbsiella quercinecans, a pathogen with an increasing prevalence: A study on the causative agents of bacterial canker of Persian walnut and oak trees in central provinces of Iran
The emerging pathogen Gibbsiella quercinecans was found in walnut and oak trees, posing a threat to Persian walnut cultivation in central provinces of Iran.
Abstract
The cultivation of Persian walnuts in Iran is concentrated in the mountainous regions of Zagros and Alborz, encompassing Kohgiluyeh and Boyer-Ahmad, Isfahan and Fars provinces. Historically, these areas were renowned for their abundant growth of oak trees. However, due to environmental stressors, oak populations in the Zagros region have been declining, leading to an increased risk of diseases caused by new and aggressive pathogens, exacerbated by climate change. Understanding the distribution and association of pathogenic bacteria in the environment, especially for less common or uncommon species, has become crucial. In this study, 80 bacterial strains were isolated from 84 symptomatic walnut and 16 symptomatic oak trees to investigate bacterial canker agents in primary walnut cultivation regions of Iran. Following the hypersensitivity test and pathogenicity assays, 21 strains were classed as ‘Brenneria nigrifluens’ or ‘Brenneria-like’, based on their similarities to the reference strain B. nigrifluens ICMP 20120 using phenotypic techniques and specific primers (F1/C3, B. nigrifluens). Varying biochemical characteristics were exhibited by the ‘Brenneria-like’ group in comparison to the ‘B. nigrifluens’ group. Multilocus sequence analysis was performed using the gyrB, rpoB, infB and atpD genes to determine the taxonomic classification of this group, revealing that it belonged to Gibbsiella quercinecans. The increasing reports of this bacterium from different woodland tree hosts suggest its opportunistic role as an individual causative agent, necessitating monitoring of its host expansion and morbidity.
Evaluation of native isolates of Trichoderma spp. for controlling potato late blight caused by Phytophthora infestans in Nepal
Abstract
Late blight, caused by Phytophthora infestans, is the most devastating disease of potato worldwide that can cause up to 100% crop loss under disease conducive conditions. The present study was carried out to evaluate and identify effective Trichoderma isolates against the disease. Thirty-nine isolates of Trichoderma spp. isolated at Nepal Plant Disease and Agro Associates (NPDA), Kathmandu from Likhu areas of Nuwakot, Nepal were screened against P. infestans in detached leaf assay for their efficacy in reducing the lesion size of late blight. Fifteen isolates significantly reduced lesion size by 19%–46% compared with the control (water spray). Of them, top 10 isolates along with Sanjeevni (T. viride), a commercial product were tested in field experiments under natural epiphytotic conditions at Thansing and Dhikure of Likhu Rural Municipality in 2020–2021 and 2022–2023 crop years, respectively. The Trichoderma isolates significantly (p < .001) increased plant growth, tuber yield and reduced disease severity in both years. In 2020–2021, isolates, TL1-2A, TL4-81A and TL5-21A reduced disease severity by 37.3%, 37.2% and 30.4%, respectively. The isolate TL1-2A also significantly increased plant height, ground coverage and tuber yield by 41.2%, 30.3% and 72.3%, respectively compared with the control (water spray). In 2022–2023, TL1-2A reduced disease severity by 40.2% and increased tuber yield by 46.4%. Other isolates, though significantly different from control, did not have satisfactory effect on disease control and tuber yield. In both years, the isolate TL1-2A significantly reduced the disease, and increased plant growth and tuber yield. Thus, TL1-2A isolate can be a potential candidate as a biocontrol agent for the integrated management of potato late blight in Nepal.
Approaching 25 years of progress towards Fusarium head blight resistance in southern soft red winter wheat (Triticum aestivum L.)
Abstract
Tremendous progress has been made in variety development and host plant resistance to mitigate the impact of Fusarium head blight (FHB) since the disease manifested in the southeastern United States in the early 2000s. Much of this improvement was made possible through the establishment of and recurring support from the US Wheat & Barley Scab Initiative (USWBSI). Since its inception in 1997, the USWBSI has enabled land-grant institutions to make advances in reducing the annual threat of devastating FHB epidemics. A coordinated field phenotyping effort for annual germplasm screening has become a staple tool for selection in public and private soft red winter wheat (SRWW) breeding programmes. Dedicated efforts of many SRWW breeders to identify and utilize resistance genes from both native and exotic sources provided a strong foundation for improvement. In recent years, implementation of genomics-enabled breeding has further accelerated genetic gains in FHB resistance. This article reflects on the improvement of FHB resistance in southern SRWW and contextualizes the monumental progress made by collaborative, persistent, and good old-fashioned cultivar development.
Genotypic stability in root system architecture and aboveground biomass revealed diverse adaptability of peanut (Arachis hypogaea L.) to moderate water deficit
Abstract
Many crop species, including cultivated peanut (Arachis hypogaea L.), modify their above- and below-ground growth to cope with water deficit stress. This acclimation to water deficit often triggers a biomass partitioning shift—allocating more biomass to the roots, to increase the accessibility of roots to water resources. However, additional carbon partitioning to roots may not always translate into increased water use and maintenance of aboveground biomass (ABM) and yield. Therefore, selecting an efficient root system architecture (RSA) should aim to sustain a high ABM production under a water deficit scenario. To better understand the associations of above and belowground biomass partitioning under moderate water deficit, this study evaluated the genotypic stability of 40 peanut genotypes in ABM and RSA in greenhouse experiments and further assessed genotypic differences in 4 site-year field experiments. Our results suggested that higher ABM-producing genotypes generally had high plasticity when subjected to water deficit whereas the low ABM-producing genotypes had relatively high stability. Hierarchical clustering analysis further revealed that genotypes with a high root-to-shoot ratio potentially had increased genotypic stability in ABM underwater deficit. Interestingly, genotypes that maintained the highest ABM underwater deficit did not have the highest total root biomass and length. Instead, these genotypes had the highest root length in the top layer of soil (0–0.3 m) and relatively fewer roots in the deeper layer of soil (0.3–1 m). Greenhouse-screened stable genotypes exhibited minimal yield reduction when subjected to mid-season water deficit in some of the field validation experiments, but it also happened to some plastic genotypes, indicating that further validation of controlled environment screenings for genotypic water-deficit tolerance in the field is necessary.
The role of P450 enzymes in malaria and other vector‐borne infectious diseases
We review published research data on P450 enzymes from all players in vector-borne infections, that is, pathogens, vectors, and hosts, regarding the potential role of CYPs in disease. We discuss strategies on how to exploit cytochromes P450 in vector-borne disease control.
Abstract
Vector-borne infectious diseases are still an important global health problem. Malaria is the most important among them, mainly pediatric, life-threatening disease. Malaria and other vector-borne disorders caused by parasites, bacteria, and viruses have a strong impact on public health and significant economic costs. Most vector-borne diseases could be prevented by vector control, with attention to the ecological and biodiversity conservation aspects. Chemical control with pesticides and insecticides is widely used as a measure of prevention although increasing resistance to insecticides is a serious issue in vector control. Metabolic resistance is the most common mechanism and poses a big challenge. Insect enzyme systems, including monooxygenase CYP P450 enzymes, are employed by vectors mainly to metabolize insecticides thus causing resistance. The discovery and application of natural specific inhibitors/blockers of vector P450 enzymes as synergists for commonly used pesticides will contribute to the “greening” of insecticides. Besides vector CYPs, host CYP enzymes could also be exploited to fight against vector-borne diseases: using mostly their detoxifying properties and involvement in the immune response. Here, we review published research data on P450 enzymes from all players in vector-borne infections, that is, pathogens, vectors, and hosts, regarding the potential role of CYPs in disease. We discuss strategies on how to exploit cytochromes P450 in vector-borne disease control.
Caffeic acid phenethyl ester surmounts acquired resistance of AZD9291 in non‐small cell lung cancer cells
We developed and characterized a new tyrosine kinase inhibitor resistant non-small cell lung cancer (NSCLC) line, HCC827GR, which (1) was significantly resistant to both gefitinib and AZD9291; (2) had more in vitro tumorigenic potential as evident by a larger colony size from the anchorage-independent growth assay; and (3) exhibited a total of 26 differentially expressed genes (≥two fold-change) as compared to HCC827. These genes were involved in regulating cell growth, transcription, phase 1 metabolism, cell cycle, and apoptosis. Additionally, AZD9291 in combination with CAPE partially reverted the AZD9291 resistance in HCC827GR cells. This was exhibited by (1) synergistically suppressed cell viability; (2) cell cycle arrest and apoptosis induced through suppressing EGFR activation and modulating p53, p21, cyclin D1, and survivin protein expressions; and (3) differentially regulating genes involved in cancer drug resistance pathways.
Abstract
Epithelial growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are the first-line therapy for EGFR mutated non-small cell lung cancer (NSCLC); however, resistance rapidly develops. The objective of this study was therefore to establish and characterize a gefitinib resistant NSCLC line (HCC827GR) and evaluate the therapeutic effects of natural products in combination with third-generation EGFR-TKI, AZD9291. The IC50 of gefitinib and AZD9291 in HCC827GR were significantly higher than those of HCC827 (p < 0.05). Furthermore, anchorage-independent colony assay indicated that HCC827GR cells were more aggressive than their predecessors. This was reflected by the gene/protein expression changes observed in HCC827GR versus HCC827 profiled by cancer drug resistance real-time polymerase chain reaction (RT-PCR) array and Western blot. Three natural products were screened and caffeic acid phenethyl ester (CAPE) exhibited the most significant combinative cytotoxic effect with AZD9291. Specifically, flow cytometry revealed that AZD9291 + CAPE considerably increased the fraction of cell in pre-G1 of the cell cycle and caspase-Glo3/7 assay showed a dramatic increase in apoptosis when compared to AZD9291 alone. Furthermore, Western blot showed significant downregulation of p-EGFR/p-AKT in HCC827GR cells treated with AZD9291 + CAPE as compared to AZD9291. Moreover, it is evident that AZD9291 + CAPE specifically resulted in a marked reduction in the protein expressions of the cell-proliferation-related genes p21, cyclin D1, and survivin. Finally, refined RT-PCR/Western blot data indicated that AZD9291 + CAPE may at least partially exert its synergistic effects via the PLK2 pathway. Together, these results suggest that CAPE is a clinically relevant compound to aid AZD9291 in treating EGFR-TKI resistant cells through modulating critical genes/proteins involved in cancer resistance/therapy.
Soybean red crown rot: Current knowledge and future challenges
Soybean red crown rot caused by the soilborne fungus Calonectria ilicicola is emerging as a significant constraint to soybean production worldwide, requiring prompt action.
Abstract
Soybean red crown rot (RCR) is caused by the soilborne fungal pathogen Calonectria ilicicola. It causes root rot, leaf senescence, early defoliation, plant wilting and even death, often resulting in a severe reduction in seed yield and quality. C. ilicicola is an extremely difficult pathogen to control owing to its wide host range and long survival in soil and plant debris. Currently, no practically effective fungicide for this pathogen is available. Breeding for resistance is considered the most effective and environmentally acceptable means of disease management, but no C. ilicicola-resistant soybean variety has yet been identified. Given this situation, it is necessary to promote our understanding of the mechanism of RCR incidence and the development of a comprehensive and sustainable RCR management strategy urgently.
Effects of sulfate on the photosynthetic physiology characteristics of Hydrocotyle vulgaris under zinc stress
Xiaoyan He, Shiling Liu, Xiaoqian Huang, Fangming Yu, Yi Li, Furong Li, Kehui Liu - Volume 50(9)
RALF‐like peptide improves the colonization of endophytic Colletotrichum tofieldiae through interacting with plant receptor‐like kinase
Endophytic Colletotrichum tofieldiae harbours RALF homologues to regulate symbiotic signals and promote hyphae colonization through interacting with FERONIA encoded by plant.
Abstract
Endophytes can colonize a host plant without inducing obvious disease symptoms. Elicitors from endophytes may play important roles in balancing endophyte colonization. We identified a novel endophytic elicitor from Colletotrichum tofieldiae, CtRALF, that has structural and functional characteristics similar to those of rapid alkalinization factor (RALF) peptides in Arabidopsis thaliana. We found that CtRALF can directly interact with the host plant receptor-like kinase FERONIA (FER). The colonization of FER mutant plants by hyphae of C. tofieldiae was obviously reduced compared with that on wild-type plants. Furthermore, the interaction of CtRALF with FER regulated symbiotic signals by triggering calcium waves, inhibiting reactive oxygen species bursts, increasing mitogen-activated protein kinase phosphorylation and reducing the stabilization of MYC2. Collectively, these results suggested that the RALF homologue of endophytes may improve their symbiosis by interacting with host plant-encoded FER.