Nanodosimetric quantity-weighted dose optimization for carbon-ion treatment planning.

Dose verification of treatment plans is an essential step in radiotherapy workflows. In this work, we propose a novel method of treatment planning based on nanodosimetric quantity-weighted dose (NQWD), which could realize biological representation using pure physical quantities for biological-oriented carbon ion-beam treatment plans and their direct verification. The relationship between nanodosimetric quantities and relative biological effectiveness (RBE) was studied with the linear least-squares method for carbon-ion radiation fields. Next, under the framework of the matRad treatment planning platform, NQWD was optimized using the existing RBE-weighted dose (RWD) optimization algorithm. The schemes of NQWD-based treatment planning were compared with the RWD treatment plans in term of the microdosimetric kinetic model (MKM). The results showed that the nanodosimetric quantity F3 - 10 had a good correlation with the radiobiological effect reflected by the relationship between RBE and F3 - 10. Moreover, the NQWD-based treatment plans reproduced the RWD plans generally. Therefore, F3 - 10 could be adopted as a radiation quality descriptor for carbon-ion treatment planning. The novel method proposed herein not only might be helpful for rapid physical verification of biological-oriented ion-beam treatment plans with the development of experimental nanodosimetry, but also makes the direct comparison of ion-beam treatment plans in different institutions possible. Thus, our proposed method might be potentially developed to be a new strategy for carbon-ion treatment planning and improve patient safety for carbon-ion radiotherapy.

Bacillus subtilis YZ-1 surfactins are involved in effective toxicity against agricultural pests.

BACKGROUND: Insect pests negatively affect crop quality and yield. The excessive use of chemical pesticides has serious impacts on the environment and food safety. Therefore, development of effective management strategies in the form of bio-agents have important agricultural applications. Tenebrio molitor, a storage pest, causes losses of grains, medicinal materials, and various agricultural and related products in the warehouse. Bacillus subtilis YZ-1 isolated from naturally deceased Pieris rapae has been found to exhibit significant toxicity against T. molitor. RESULTS: Treatment with B. subtilis YZ-1 fermentation broth resulted in a 90-95% mortality rate of T. molitor within 36 h post-treatment, indicating some active substances may have insecticidal activity in the bacterial supernatant. A bioactivity-guided fractionation method was used to isolate the insecticidal compounds from YZ-1, which led to the identification of surfactins. Additionally, a surfactin deletion mutant YZ-1△srfAA was constructed and the surfactin production by the mutant YZ-1△srfAA was verified through liquid chromatography-mass spectrometry (LC-MS). Further, YZ-1△srfAA exhibited loss of insecticidal activity against T. molitor, Plutella xylostella and Achelura yunnanensis. The insecticidal activity and surfactins contents of several strains of Bacillus sp. were also tested and correlation was found between varying surfactins yield and insecticidal activity exhibited by different strains. CONCLUSION: Conclusively, our results suggest that B. subtilis YZ-1 may provide a novel approach for plant protection against agricultural pests. © 2023 Society of Chemical Industry.

Bacillus amyloliquefaciens AK-12 Helps Rapeseed Establish a Protection against Brevicoryne brassicae.

Aphids are a serious threat to rapeseed (Brassica napus L.) production, and cause unmanageable loss. Therefore, effective prevention and management strategies are urgently required to avoid losses. Bacillus amyloliquefaciens AK-12 isolated from a dead aphid with aphicidal activity was tagged with a green fluorescent protein through a natural transformation. The transformed strains were checked for stability and growth, and the best-performing strain was tested for its colonization inside and outside the rapeseed plant. The stability of AK-12-GFP reached more than 95%, and the growth curve was consistent with that of AK-12. After 30 days of treatment, the colonization of 1 × 106 CFU/g was recorded in rapeseed leaves. Interestingly, AK-12 reduced the aphid transmission rate compared with the control and improved the growth of the rapeseed seedlings. Meanwhile, the AK-12 strain also exhibited phosphorus, potassium-solubilizing, and nitrogen-fixing activity, and produced 2.61 µg/mL of IAA at 24 h. Regulation in the activity of four enzymes was detected after the AK-12 treatment. Phenylalanine ammonia lyase (PAL) was recorded at a maximum of 86.84 U/g after 36 h, and catalase (CAT) decreased after 48 h; however, peroxidase (POD) and polyphenol oxidase (PPO) reached the maximum within 12 h of AK-12 application. Additionally, important resistance genes related to these enzymes were upregulated, indicating the activation of a defense response in the rapeseed against aphids. In conclusion, defense enzymes and defense-related gene activation could improve the pest resistance in rapeseed, which has good application prospects for the future to be developed into biopesticide.

Biodistributions and Imaging of Poly(ethylene glycol)-Conjugated Silicon Quantum Dot Nanoparticles in Osteosarcoma Models via Intravenous and Intratumoral Injections.

Osteosarcoma is a malignant tumor with relatively high mortality rates in children and adolescents. While nanoparticles have been widely used in assisting the diagnosis and treatment of cancers, the biodistributions of nanoparticles in osteosarcoma models have not been well studied. Herein, we synthesize biocompatible and highly photoluminescent silicon quantum dot nanoparticles (SiQDNPs) and investigate their biodistributions in osteosarcoma mouse models after intravenous and intratumoral injections by fluorescence imaging. The bovine serum albumin (BSA)-coated and poly(ethylene glycol) (PEG)-conjugated SiQDNPs, when dispersed in phosphate-buffered saline (PBS), can emit red photoluminescence with the photoluminescence quantum yield more than 30% and have very low in vitro and in vivo toxicity. The biodistributions after intravenous injections reveal that the SiQDNPs are mainly metabolized through the livers in mice, while only slight accumulation in the osteosarcoma tumor is observed. Furthermore, the PEG conjugation can effectively extend the circulation time. Finally, a mixture of SiQDNPs and indocyanine green (ICG), which complement each other in the spectral range and diffusion length, is directly injected into the tumor for imaging. After the injection, the SiQDNPs with relatively large particle sizes stay around the injection site, while the ICG molecules diffuse over a broad range, especially in the muscular tissue. By taking advantage of this property, the difference between the osteosarcoma tumor and normal muscular tissue is demonstrated.

Deep learning-based fast denoising of Monte Carlo dose calculation in carbon ion radiotherapy.

BACKGROUND: Plan verification is one of the important steps of quality assurance (QA) in carbon ion radiotherapy. Conventional methods of plan verification are based on phantom measurement, which is labor-intensive and time-consuming. Although the plan verification method based on Monte Carlo (MC) simulation provides a more accurate modeling of the physics, it is also time-consuming when simulating with a large number of particles. Therefore, how to ensure the accuracy of simulation results while reducing simulation time is the current difficulty and focus. PURPOSE: The purpose of this work was to evaluate the feasibility of using deep learning-based MC denoising method to accelerate carbon-ion radiotherapy plan verification. METHODS: Three models, including CycleGAN, 3DUNet and GhostUNet with Ghost module, were used to denoise the 1 × 106 carbon ions-based MC dose distribution to the accuracy of 1 × 108 carbon ions-based dose distribution. The CycleGAN's generator, 3DUNet and GhostUNet were all derived from the 3DUNet network. A total of 59 cases including 29 patients with head-and-neck cancers and 30 patients with lung cancers were collected, and 48 cases were randomly selected as the training set of the CycleGAN network and six cases as the test set. For the 3DUNet and GhostUNet models, the numbers of training set, validation set, and test set were 47, 6, and 6, respectively. Finally, the three models were evaluated qualitatively and quantitatively using RMSE and three-dimensional gamma analysis (3 mm, 3%). RESULTS: The three end-to-end trained models could be used for denoising the 1 × 106 carbon ions-based dose distribution, and their generalization was proved. The GhostUNet obtained the lowest RMSE value of 0.075, indicating the smallest difference between its denoised and 1 × 108 carbon ions-based dose distributions. The average gamma passing rate (GPR) between the GhostUNet denoising-based versus 1 × 108 carbon ions-based dose distributions was 99.1%, higher than that of the CycleGAN at 94.3% and the 3DUNet at 96.2%. Among the three models, the GhostUNet model had the fewest parameters (4.27 million) and the shortest training time (99 s per epoch) but achieved the best denoising results. CONCLUSION: The end-to-end deep network GhostUNet outperforms the CycleGAN, 3DUNet models in denoising MC dose distributions for carbon ion radiotherapy. The network requires less than 5 s to denoise a sample of MC simulation with few particles to obtain a qualitative and quantitative result comparable to the dose distribution simulated by MC with relatively large number particles, offering a significant reduction in computation time.

First report of Colletotrichum siamense as a causal agent of anthracnose on wax apple (Syzygium samarangense) in China.

Wax apple (Syzygium samarangense) is an important fruit tree widely cultivated in China. Yield losses are usually serious due to different diseases among which anthracnose (Colletotrichum spp.) is one of the most damaging (He et al, 2019). This disease was found in Yunnan, China and an average incidence of 56.7% diseased leaves was recorded in21 orchards surveyed in July2021. The disease lesions on leaves were circular, angular or oval (7.2-15.6 mm), with whitish center and brown outer area surrounded by a yellow halo; irregular spots or blight areas formed later. It can also infect fruits forming pale-brown, circular and sunken spots before harvest and rot of stored fruits. Diseased leaves were sampled from orchards in Ximeng (N117.78oE39.89o) and Ninger (E101.04oN23.05o) counties of Yunnan for fungal isolation; three and five pure isolates were recovered from Ximeng (LWTJ1-LWTJ3) and Ninger (LB4-LB8) samples, respectively, by plating disinfested tissue (surface-sterilized with 2% NaClO3) on potato dextrose agar (PDA) followed by hyphal tip purification and incubation at 25oC. Two repeated tests following Koch's postulates were conducted to verify pathogenicity of the eight isolates. In each test, three healthy seedlings per isolate were sprayed with conidia suspenson (2.26×105cfu/mL) until runoff from leaves while control plants were sprayed with sterile water. The plants were kept in the dark at RH100 for 24 h in a black box and then in a growth chamber (28oC, RH>90% and lighting 12h/d). Detached fruits were inoculated with mycelial discs on the puncture-wound surface. Anthracnose symptoms developed on all seedlings and fruits inoculated with LWTJ2 or LB4 isolates, which were re-isolated from lesions of inoculated leaf/fruit, completing Koch's postulates. Control plants were healthy and symptomless. LWTJ2 and LB4 isolates were morphologically the same: the colonies on PDA were circular, pale-white, with cottony surface and readily forming orange conidium masses. The hyphae were hyaline, septate, branched mostly in near right angles. The conidia were hyaline, one-celled, smooth-walled, cylindrical with round ends, 9.8-17.5 (av.13.8) µm×4.4-6.5 (5.6) µm. The teleomorph was not observed in culture or on orchard trees. The morphological characters were consistent with those of C. siamense described by Weir et al (2012). The internal transcribed spacer region (ITS) was amplified from the two isolates by PCR and sequenced (1990) and were 545 bp in length (OL963924 & OL413460). BLAST analysis showed that both were 100% identical and they shared 99.08% identity with C. siamense WZ-365 from the ITS region (MN856443).The Tub2 (788 bp, ON637119) and Cal (768 bp, ON622249) genes (Weir et al, 2012) of LB4 were also obtained and they shared closest identity (99.45% & 100%) with those of C. siamense WZ-365 as well. Phylogenetic tree (neighbor-joining) analysis of the concatenated sequence of ITS, Tub2 and Cal genes of LB4 and those of related Colletotrichum spp. showed that LB4 clustered IN the same end-branch with C. siamense ICMP18578 (Bootstrap sup. = 98%). Thus, C. siamense was identified as the pathogen of wax apple anthracnose in Yunnan. It caused anthracnose on other crops as oranges and cacao (Azad et al, 2020). Also, C. fructicola and C. syzygicola were identified as pathogens of wax apple anthracnose in Thailand (Al-Obaidi et al, 2017). To our knowledge, this is the first report of C. siamense causing wax apple anthracnose in China.

Biodegradable germanium nanoparticles as contrast agents for near-infrared-II photoacoustic imaging.

Photoacoustic (PA) imaging using contrast agents with strong near-infrared-II (NIR-II, 1000-1700 nm) absorption enables deep penetration into biological tissue. Besides, biocompatibility and biodegradability are essential for clinical translation. Herein, we developed biocompatible and biodegradable germanium nanoparticles (GeNPs) with high photothermal stability as well as strong and broad absorption for NIR-II PA imaging. We first demonstrate the excellent biocompatibility of the GeNPs through experiments, including the zebrafish embryo survival rates, nude mouse body weight curves, and histological images of the major organs. Then, comprehensive PA imaging demonstrations are presented to showcase the versatile imaging capabilities and excellent biodegradability, including in vitro PA imaging which can bypass blood absorption, in vivo dual-wavelength PA imaging which can clearly distinguish the injected GeNPs from the background blood vessels, in vivo and ex vivo PA imaging with deep penetration, in vivo time-lapse PA imaging of a mouse ear for observing biodegradation, ex vivo time-lapse PA imaging of the major organs of a mouse model for observing the biodistribution after intravenous injection, and notably in vivo dual-modality fluorescence and PA imaging of osteosarcoma tumors. The in vivo biodegradation of GeNPs is observed not only in the normal tissue but also in the tumor, making the GeNPs a promising candidate for clinical NIR-II PA imaging applications.

First report of Aloe root and stem rot caused by Phytophthora palmivora in Yunnan Province, China.

Aloe genus plants are perennial evergreen herb belonging to Liliaceae family which is widely used in food, medicine, beauty, and health care (Kumar et al. 2019). In August 2021, symptoms of root and stem rot was observed in approximately 20% of Aloe vera plantings in Yuanjiang County, Yunnan Province, China (23° 64' 53" N, 101° 99' 84" E). The most typical symptoms were stem and root rot, browning and necrosis of vascular tissues, gradual greening, and reddish-browning of leaves from bottom to top, abscission, and eventual plant death (Fig. S1). Therefore, to isolate and identify the pathogen, the plants showing the above symptoms were collected. The plant tissues were cut from the edges of root and stem lesions, followed by disinfection with 75% ethanol for 1 min, rinsed three times with sterilized distilled water, and cut into 3 × 3 mm small squares after excision of marginal tissues. The tissues were transferred to the oomycetes selective medium (Liu et al. 2022) and incubated at 28 °C in the dark for 3~5 days, and suspected colonies were purified. The colonies were then inoculated onto potato dextrose agar (PDA), V8-juice agar (V8), and oatmeal agar (OA) medium plates for morphological characteristics. Finally, 18 isolates with the same colonial and morphological characteristics were obtained from 30 lesioned tissue and one of them was named as ARP1. On PDA, V8 and OA medium plates, the ARP1 colonies were white. On PDA plate, the mycelia were dense and the colonies were petal-like; on V8 plate, the mycelia were cashmere and the colonies were radial or star-like. Whereas, on OA plate, the mycelia were cotton-like and the colonies were fluffy and radial (Fig. S2 A~C). Mycelium did not have septum with high branching and swelling. Sporangia were abundant, semi-papillate, varying in shape from ovoid-ellipsoid to long-ellipsoid, 18-26 × 45-63 µm (average: 22 × 54 µm, n = 30), sporangia released numerous zoospores from the papillate after maturation. The chlamydospores were spherical, 20-35 µm in diameter (average: 27.5 µm, n = 30) (Fig. S2 D~F). These morphological features were like those of the pathogenic species of the oomycetes (Chen et al. 2022). For the molecular characterization, the genomic DNA of the isolate was extracted using the cetyl trimethyl ammonium bromide method, and the translation elongation factor 1α (tef-1α) (Stielow et al. 2015), ß-tubulin (ß-tub) (Kroon et al. 2004) and internal transcribed spacer (ITS) (White et al. 1990) of isolated strain ARP1 were amplified using primer pairs EF1-1018F/EF1-1620R, TUBUF2/TUBUR1 and ITS1/ITS4, respectively. The tef-1α, ß-tub genes and ITS region of ARP1 were directly sequenced and their sequence information was deposited in GenBank under accession numbers OQ506129, OQ506127 and OQ449628. ARP1 was clustered on the same evolutionary branch with Phytophthora palmivora (Fig. S3). To confirm the pathogenicity of ARP1, the main root of A. vera was wounded to 1 cm long and 2 mm deep with a scalpel blade followed by inoculation with 50 ml suspension of ARP1 zoospores at a concentration of 1 × 106 spores / ml per potted plant, and an equal volume of water as control. All inoculated plants were placed in the greenhouse at 28°C, 12 h / 12 h light / dark. After 15 dpi, the inoculated plants showed typical symptoms of wilted and drooping leaves and stem and root rot, same as observed in the field condition (Fig. S4). After inoculation with ARP1, a strain with the same morphological and molecular characteristics as the original isolate was re-isolated, confirming Koch's postulates. To our knowledge, this is the first report of P. palmivora causing root and stem rot of A. vera in the study region. This disease could be a potential risk for aloe production and therefore appropriate management measures should be taken.

Implantable QR code subcutaneous microchip using photoacoustic and ultrasound microscopy for secure and convenient individual identification and authentication.

Individual identification and authentication techniques are merged into many aspects of human life with various applications, including access control, payment or banking transfer, and healthcare. Yet conventional identification and authentication methods such as passwords, biometrics, tokens, and smart cards suffer from inconvenience and/or insecurity. Here, inspired by quick response (QR) code and implantable microdevices, implantable and minimally-invasive QR code subcutaneous microchips (QRC-SMs) are proposed to be an effective approach to carry useful and private information, thus enabling individual identification and authentication. Two types of QRC-SMs, QRC-SMs with "hole" and "flat" elements and QRC-SMs with "titanium-coated" and "non-coated" elements, are designed and fabricated to store personal information. Corresponding ultrasound microscopy and photoacoustic microscopy are used for imaging the QR code pattern underneath skin, and open-source artificial intelligence algorithm is applied for QR code detection and recognition. Ex vivo experiments under tissue and in vivo experiments with QRC-SMs implanted in live mice have been performed, demonstrating successful information retrieval from implanted QRC-SMs. QRC-SMs are hidden subcutaneously and invisible to the eyes. They cannot be forgotten, misplaced or lost, and can always be ready for timely medical identification, access control, and payment or banking transfer. Hence, QRC-SMs provide promising routes towards private, secure, and convenient individual identification and authentication.

Biocontrol of plant pathogens in omics era-with special focus on endophytic bacilli.

Nearly all plants and their organs are inhabited by endophytic microbes which play a crucial role in plant fitness and stress resilience. Harnessing endophytic services can provide effective solutions for a sustainable increase in agriculture productivity and can be used as a complement or alternative to agrochemicals. Shifting agriculture practices toward the use of nature-based solutions can contribute directly to the global challenges of food security and environmental sustainability. However, microbial inoculants have been used in agriculture for several decades with inconsistent efficacy. Key reasons of this inconsistent efficacy are linked to competition with indigenous soil microflora and inability to colonize plants. Endophytic microbes provide solutions to both of these issues which potentially make them better candidates for microbial inoculants. This article outlines the current advancements in endophytic research with special focus on endophytic bacilli. A better understanding of diverse mechanisms of disease control by bacilli is essential to achieve maximum biocontrol efficacy against multiple phytopathogens. Furthermore, we argue that integration of emerging technologies with strong theoretical frameworks have the potential to revolutionize biocontrol approaches based on endophytic microbes.

Fengycin produced by Bacillus subtilis XF-1 plays a major role in the biocontrol of Chinese cabbage clubroot via direct effect and defense stimulation.

Bacillus subtilis XF-1 is a well-investigated biocontrol agent against the biotrophic Plasmodiophora brassicae Woron., the causal agent of clubroot disease of cruciferous crops. The present study demonstrates that XF-1 could efficiently control clubroot disease via leaf spraying and provides an understanding of the biocontrol mechanisms. High-performance thin-layer chromatography (HTPLC) analysis indicated the presence of fengycin-type cyclopeptides in the supernatant. A ppsB deletion mutant of XF-1 resulted in no fengycin production, significantly reduced the lysis rate of testing spores in vitro and the primary infection rate of root hair in vivo, and decreased the protection value against clubroot disease under the greenhouse conditions. Confocal laser scanning microscopy proved that fengycin was not required for leaf internalization and root colonization. Moreover, the expression level of the ppsB gene in XF-1 was regulated by its cell density in root during interaction with P. brassicae. In addition, the ΔppsB mutant of XF-1 could not efficiently control disease because it led to a lower activation level of the jasmonic acid and salicylic acid signaling pathways in roots, which are necessary for the plant defense reaction upon pathogen invasion. Altogether, the present study provides a new understanding of specific cues in the interaction between B. subtilis and P. brassicae as well as insights into the application of B. subtilis in agriculture.

Environmental effect of agriculture-related manufactured nano-objects on soil microbial communities.

Agriculture-related manufactured nano-objects (MNOs) can revolutionize the crop production and help to achieve sustainable development goals. MNOs with diverse physico-chemical properties and ability to encapsulate and deliver active ingredients in controlled, targeted and stimuli responsive manner can enhance the efficiency while minimizing collateral damage to non-target organisms and environment. Application of MNOs in the form of nanopesticides and nanofertilizers is known to affect soil microbial communities both positively and negatively, but detailed studies with varying dose, type and environmental conditions are scarce. Therefore, it is imperative to understand the complex mechanisms and factors which shape the MNOs-microbial interactions through integrating state of the art technologies including omics (transcriptomics, metabolomics, and proteomics), artificial intelligence, and statistical frameworks. Lastly, we propose the idea of MNOs-mediated manipulation of soil microbiome to modify the soil microbial communities for improved microbial services. These microbial services, if harnessed appropriately, can revolutionize modern agriculture and help in achieving sustainable development goals.

Uniting the Role of Endophytic Fungi against Plant Pathogens and Their Interaction.

Endophytic fungi are used as the most common microbial biological control agents (MBCAs) against phytopathogens and are ubiquitous in all plant parts. Most of the fungal species have roles against a variety of plant pathogens. Fungal endophytes provide different services to be used as pathogen control agents, using an important aspect in the form of enhanced plant growth and induced systemic resistance, produce a variety of antifungal secondary metabolites (lipopeptides, antibiotics and enzymes) through colonization, and compete with other pathogenic microorganisms for growth factors (space and nutrients). The purpose of this review is to highlight the biological control potential of fungal species with antifungal properties against different fungal plant pathogens. We focused on the introduction, biology, isolation, identification of endophytic fungi, and their antifungal activity against fungal plant pathogens. The endosymbionts have developed specific genes that exhibited endophytic behavior and demonstrated defensive responses against pathogens such as antibiosis, parasitism, lytic enzyme and competition, siderophore production, and indirect responses by induced systemic resistance (ISR) in the host plant. Finally, different microscopic detection techniques to study microbial interactions (endophytic and pathogenic fungal interactions) in host plants are briefly discussed.

Novel Virulence Factors Deciphering Klebsiella pneumoniae KpC4 Infect Maize as a Crossing-Kingdom Pathogen: An Emerging Environmental Threat.

Klebsiella pneumoniae is not only a human and animal opportunistic pathogen, but a food-borne pathogen. Cross-kingdom infection has been focused on since K. pneumoniae was identified as the pathogen of maize, banana, and pomegranate. Although the pathogenicity of K. pneumoniae strains (from ditch water, maize, and human) on plant and mice has been confirmed, there are no reports to explain the molecular mechanisms of the pathogen. This study uncovered the K. pneumoniae KpC4 isolated from maize top rot for the determination of various virulence genes and resistance genes. At least thirteen plant disease-causing genes are found to be involved in the disruption of plant defense. Among them, rcsB is responsible for causing disease in both plants and animals. The novel sequence types provide solid evidence that the pathogen invades plant and has robust ecological adaptability. It is imperative to perform further studies on the verification of these KpC4 genes' functions to understand the molecular mechanisms involved in plant−pathogen interactions.

In vivo evaluation of a lipopolysaccharide-induced ear vascular leakage model in mice using photoacoustic microscopy.

Sepsis is caused by dysregulated host inflammatory response to infection. During sepsis, early identification and monitoring of vascular leakage are pivotal for improved diagnosis, treatment, and prognosis. However, there is a lack of research on noninvasive observation of inflammation-related vascular leakage. Here, we investigate the use of photoacoustic microscopy (PAM) for in vivo visualization of lipopolysaccharide (LPS)-induced ear vascular leakage in mice using Evans blue (EB) as an indicator. A model combining needle pricking on the mouse ear, topical smearing of LPS on the mouse ear, and intravenous tail injection of EB is developed. Topical application of LPS is expected to induce local vascular leakage in skin. Inflammatory response is first validated by ex vivo histology and enzyme-linked immunosorbent assay. Then, local ear vascular leakage is confirmed by ex vivo measurement of swelling, thickening, and EB leakage. Finally, PAM for in vivo identification and evaluation of early vascular leakage using the model is demonstrated. For PAM, common excitation wavelength of 532 nm is used, and an algorithm is developed to extract quantitative metrics for EB leakage. The results show potential of PAM for noninvasive longitudinal monitoring of peripheral skin vascular leakage, which holds promise for clinical sepsis diagnosis and management.

Potential of citrus endophyte Bacillus subtilis L1-21 in the control of Candidatus Liberibacter asiaticus in Asian citrus psyllid, Diaphorina citri.

BACKGROUND: Asian citrus psyllid (ACP), also known as Diaphorina citri, is the natural vector of Candidatus Liberibacter asiaticus (CLas), which is responsible for Huanglongbing (HLB), a devastating citrus disease. Previously, the pathogen was successfully excluded from diseased citrus plants by using the indigenous endophyte Bacillus subtilis L1-21. However, the pathogen elimination and colonization potential of B. subtilis L1-21 in the carrier vector ACP, as well as the recruitment of native microbial communities of psyllid in the presence of endophytes, are still unknown. RESULTS: Initially, we suggested that endophyte L1-21 reduced the CLas copies in ACP from 6.58 × 106 to 5.04 × 104 per insect after 48 h, however, the pathogen copies remained stable in the negative control. The endophyte was stable for 48 h after application. Among the bacterial genera those highlighted in ACP were Candidatus Liberibacter, Pseudomonas, Candidatus Profftella, Methylobacterium-Methylorubrum, Pantoea, Curtobacterium, Wolbachia, Actinomycetospora, and Bacillus. Interestingly, B. subtilis L1-21 easily colonizes the midgut of ACP but cannot be detected in eggs. When ACP with endophyte L1-21 was allowed to feed on new citrus leaves, the highest colonization was observed. We also found that psyllids carrying endophyte L1-21 after feeding on citrus leaves reduced the CLas copies in leaves on the 0, 3rd and 5th day from 8.18 × 10,4 2.6 × 10,3 and 0 pathogen copies/g fresh midvein, respectively. CONCLUSIONS: We propose that B. subtilis L1-21 is a native endophyte in citrus and psyllid, which efficiently reduces the CLas pathogen in both citrus and psyllids, provides a more protective effect by increasing the number of cultivable endophytes, and successfully colonizes the midgut of ACP. © 2022 Society of Chemical Industry.

Potential biocontrol efficiency of Trichoderma species against oomycete pathogens.

Plant health is of utmost importance for optimal agricultural production and sustainability. Unfortunately, biotic and abiotic factors put a major constraint on crop safety and productivity. Plant diseases caused by oomycetes inflict serious damage to various crops. Moreover, the injudicious use of chemical pesticides poses threats related to pesticide resistance development in pathogens and environmental pollution. Biocontrol offers an effective solution for disease control; however, research on biocontrol of oomycete-related diseases is scarce. Thus, this study undertakes the screening of biocontrol resources for the effective management of oomycete-related plant diseases. In this regard, 86 isolates of Trichoderma spp. were assessed against Phytophthora nicotianae, P. capsici, Pythium vexans, P. ultimum, and P. dissotocum through dual culture assay. Furthermore, the antagonistic effect of selected isolates was studied against tobacco black shank disease and damping-off of cucumber seedlings in the greenhouse. The relative control effect of the three antagonistic Trichoderma strains AR-4, Tv-1, and ST4-1 on tobacco black shank was more than 60%, which was not significantly different from 6.88 gl-1 fluopicolide-propamocarb. Whereas, the relative control effect of Trichoderma AR-4 and ST4-1 on damping-off of cucumber seedlings was 80.33% and 82.67%, respectively, which were significantly higher than Trichoderma Tv-1 (35.49%) and fluopicolide-propamocarb (47.82%). According to the morphological and molecular characterization, the fungal strains AR-4, Tv-1, and ST4-1 were identified as Trichoderma koningiopsis, T. asperellum, and T. gamsii, respectively. In conclusion, the strains exhibited a strong antagonistic effect against oomycete pathogens and can be integrated into disease management strategies.

DR-only Carbon-ion radiotherapy treatment planning via deep learning.

PURPOSE: To evaluate the feasibility of patient-specific digital radiography (DR)-only treatment planning for carbon ion radiotherapy in anthropomorphic thorax-and-abdomen phantom and head-and-neck patients. METHODS: The study was conducted on the anthropomorphic phantom and head-and-neck patients. We collected computed tomography (CT) and DR images of the phantom and cone beam CT (CBCT) and DR images of the patients, respectively. Two different deep neural networks were established to correlate the relationships between DR and digitally reconstructed radiograph (DRR) images, as well as DRR and CT images. The similarity between CT and predicted CT images was evaluated by computing the mean absolute error (MAE), root mean square error (RMSE), peak signal-to-noise ratio (PSNR) and structural similarity (SSIM), respectively. Dose calculations on the predicted CT images were compared against the true CT-based dose distributions for carbon-ion radiotherapy treatment planning with intensity-modulated pencil-beam spot scanning. Relative dose differences in the target volumes and organ-at-risks were computed and three-dimensional gamma analyses (3 mm, 3%) were performed. RESULTS: The average MAE, RMSE, PSNR and SSIM of the framework were 0.007, 0.144, 37.496 and 0.973, respectively. The average relative dose differences between the predicted CT- and CT-based dose distributions at the same carbon-ion irradiation settings for the phantom and the patients were <2% and ≤4%, respectively. The average gamma pass-rates were >98% for the predicted CT-based versus CT-based carbon ion plans of the phantom and the patients. CONCLUSION: We have demonstrated the feasibility of a patient-specific DR-only treatment planning workflow for heavy ion radiotherapy by using deep learning approach.

First report of a new leaf blight disease of bletilla (Bletilla striata) caused by Curvularia reesii in China.

Bletilla striata is an important Chinese herbal plant grown widely in southwest China (Qian et al. 2021). Leaf blight was found on cultivated bletilla crops in Yunnan in 2021. The disease infected bletilla leaves and it was present in the field from April to November with the highest incidence (86% plants diseased) recorded in early September in Puer area. Foliar lesions were circular (Φ0.5-1.8 cm) or oval, with pale-gray center and narrow gray-brown outer area surrounded by a yellow halo. The lesions coalesced later to form large irregular spots or blighted areas on leaves. Symptomatic bletilla leaves were sampled from fields in Jiangcheng (E101.8672o, N22.5803o) and Simao (E109.7816o, N22.7891o) counties, Yunnan in July 2021. Seven fungal isolates were obtained from (BJ01-BJ04) and Simao samples (HBJ05-HBJ07) via lesion-tissue culture and hypha-tip purification on PDA medium. A pathogenicity test following Koch's Postulates (Grimms et al. 2006) was conducted using each isolate by inoculating 45-day old bletilla plant (n=30, Zihua cultivar) in a greenhouse through spraying hypha-spore suspension (3.25×104 CFU/mL) prepared with 14 d fresh DNA culture. Non-inoculated plants (n=30) were used as controls. The experiment was repeated once. The isolates BJ02 and HBJ06 (deposited in Yunnan Agric. Univ. Microbes Herbarium) were shown pathogenic to bletilla since similar lesions formed on seedlings 7 d post inoculation and pure fungal cultures with the same colony morphology as those of BJ02 and HBJ06 were re-isolated from leaf lesions 14 dpi. Isolates BJ02 and HBJ06 produced identical colony and conidium morphology after they were incubated at 25oC for 7 d on PDA. Colonies were circular, pale brown, Φ5.5-7.5cm, with villous surface and abundant aerial hyphae. Mycelia were septate, colorless, Φ3-4 µm and with acute-angled branches. Conidiophores developed from hyphae were erect, septate, pale-brown colored and 60-200 µm long. Conidia (produced scarcely and ripened slowly) were long-oval or petaloid, straight or slightly curved, brown, sized 28-45×10-14 µm. Most conidia were divided into 4 cells by 3 septa; the middle two were bigger than the basal and apex cells. Both BJ02 and HBJ06 were identified as Curvularia sp. based on their morphological characters (Tan et al. 2018). The rDNA-ITS, TEF1α and GAPDH genes (Tan et al. 2018) were amplified from these isolates with PCR (White et al. 1990) and sequenced. ITS sequences of the two isolates were both 574 bp (acc. no. OL587997 & OL336480) and 100% (574/574 bp) identical shown by blast comparison. Further blast analyses of ITS (574 bp, OL587997), TEF1α (532 bp, ON637120) and GAPDH (881 bp, ON637121) from isolate BJ02 showed that they were 99.27% (547/551 bp), 100% (842/842 bp) and 99.8% (507/508 bp) identical respectively with those of Curvularia reesii BRIP4358 (MH414907). The 3 genes of BJ02 were concatenated and phylogenic analysis (Tamura et al, 2013) of the concatenated sequence with those of Curvularia spp. showed that BJ02 was clustered with C. reesii BRIP4358 on the same end-branch of the tree with 100% confidence. Therefore, BJ02 and HBJ06 are the same species identified as Curvularia reesii and it is the pathogen causing bletilla leaf blight. C. reesii was first isolated from the air in Australia in 1963 and was named by Tan et al. in 2018. It has not been reported as a plant pathogen elsewhere. This is the first record of this fungus causing bletilla leaf blight in China. Keywords: Bletilla striata; leaf blight; Curvularia reesii; disease symptoms; pathogen morphology; multigene identification References (1) D.J. Grimes. Microbes, 1(5): 223-228, 2006. (2) L.H. Qian et al. Jiangshu Agric. Sci. 49(19): 64-71, 2021. (3) K. Tamura et al. Mol. Bio. & Evol. 30 (12): 2725- 2729, 2013. (4) Y. P. Tan et al. MycoKeys, 35: 1-25. 2018. (5) T.J. White et al. In: PCR Protocols: A Guide to Methods and Applications (eds. M.A. Innis et al.), Acad. Press, Inc. New York. 315-322, 1990.

Phytophthora cinnamomi causing root rot on Rhododendron lapponicum and control it using potential biocontrol agents.

Rhododendron lapponicum (R. lapponicum) is a dwarf Rhododendron species, which is severely infected with root rot and wilt in Yunnan province, China. However, the causal agent causing these symptoms was unknown. An isolate, Pci-1 was identified as Phytophthora cinnamomi, based on its morphology and the sequences of ß-tubulin, internal transcribed spacer, and Ypt1 genes and verified according to the Koch's postulate. We found that this pathogen could infect 14 species of plants, including Althaea rosea, Viburnum cylindricum, and Brassica napus. Strain Pci-1 could cause R. lapponicum to wither and die; and it grows best in an oat medium with pH 7.0 - 8.0 and an optimum temperature of 27°C. We suggest that the rhizosphere of R. lapponicum treated with biocontrol strains Paenibacillus polymyxoides P2-5 and Trichoderma asperellum Tv-1 showed a significant inhibitory effect on pathogen Pci-1. The inhibitory effect of 70% dimethomorph + cymoxanil was significantly higher with EC50 and EC90 values of 0.1894 and 0.3618 a.i. µg/ml, respectively. Greenhouse experiments revealed that the pathogen load is decreased in the presence of potential antagonists. This study provides fundamentals on risk assessment and theoretical support for the management of P. cinnamomi pathogen and contributes significantly to the planting of forest and horticultural crops in a disease-free environment.