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Stem Cells International 2021Germ cells are capable of maintaining species continuity through passing genetic and epigenetic information across generations. Female germ cells mainly develop during... (Review)
Review
Germ cells are capable of maintaining species continuity through passing genetic and epigenetic information across generations. Female germ cells mainly develop during the embryonic stage and pass through subsequent developmental stages including primordial germ cells, oogonia, and oocyte. However, due to the limitation of using early human embryos as research model, research models are needed to reveal the early developmental process and related mechanisms of female germ cells. After birth, the number of follicles gradually decreases with age. Various conditions which damage ovarian functions would cause premature ovarian failure. Alternative treatments to solve these problems need to be investigated. Germ cell differentiation from pluripotent stem cells can simulate early embryonic development of female germ cells and clarify unresolved issues during the development process. In addition, pluripotent stem cells could potentially provide promising applications for female fertility preservation after proper differentiation. Mouse female germ cells have been successfully reconstructed and delivered to live offspring. However, the derivation of functional human female germ cells has not been fully achieved due to technical limitations and ethical issues. To provide an updated and comprehensive information, this review centers on the major studies on the differentiation of mouse and human female germ cells from pluripotent stem cells and provides references to further studies of developmental mechanisms and potential therapeutic applications of female germ cells.
PubMed: 33510796
DOI: 10.1155/2021/8849230 -
Plant Disease Jan 2021Camelina sativa, an herbaceous annual plant in the family Brassicaceae, is especially well known for its oilseed crop that produce camelina oil (Hovsepyan et al. 2008)....
Camelina sativa, an herbaceous annual plant in the family Brassicaceae, is especially well known for its oilseed crop that produce camelina oil (Hovsepyan et al. 2008). In April 2016, white blister rust disease on C. sativa were observed in a cultivated farmland with an incidence of about 60% in Xinyuan County (43°33'39.17"N, 83°14'54.04"E), Xinjiang, China. Symptoms appeared as light-yellow chlorotic spots on the upper surface of the leaves and white blister on the corresponding lower surface. Blister sori were white, oval to ellipsoidal, scattered or coalesce, and 1.8 to 4 mm in diameter. Two representative voucher specimens were deposited in the Mycological Herbarium of Tarim University (HMUT 2527 and HMUT 2528), Aral, China. Sporangiophores hyaline, clavate or cylindrical, straight to slightly curved, (23.7 to) 27.9 to 37.9 (to 42.1) (av. 31) × (7.9 to) 9.6 to 13.7 (to 15.1) (av. 11.4) μm (n = 30), thick-walled on their lower parts, bearing sporangia in chains. Primary sporangia were globose to subglobose, wall equal thickness, and (9.5 to) 10.6 to 13.2 (to 14.3) (av. 11.9) μm in diameter (n = 50). Secondary sporangia were mostly subglobose to ovoid, with a subtruncated base, and (12.1 to) 13.2 to 16.9 (to 18) (av. 15.1) μm × (11 to) 12.1 to 15 (to 16.1) (av. 13.4) μm in size (n = 50). Oogonia were globose to subglobose, (39.7 to) 42.7 to 51.7 (to 54.1) (av. 48.3) μm in diameter (n = 30), irregular. Oospores were globose to subglobose, brown, (34.5 to) 37 to 42.7 (to 45.2) (av. 41.1) μm in diameter (n = 30), 3 to 5 μm wall in thickness, with single warts, 1.5 to 4 × 2 to 3.5 μm (n = 30). The morphological characteristics of specimens were consistent with those of Albugo koreana (Choi et al. 2007). To confirm the identification, genomic DNA were extracted directly from sori on diseased leaves from isolates HMUT 2527 and HMUT 2528, respectively. The internal transcribed spacer (ITS) rDNA and cytochrome oxidase II (cox2) mtDNA were amplified with primers DC6/LR-0 described by Choi et al. (2006) and cox2-F/cox2-R described by Hudspeth et al. (2000), respectively. A BLASTn search revealed that the ITS rDNA sequences (GenBank accession Nos. MW135444 and MW135445) were 99% (838/844 nucleotides)identical to that of A. koreana from Capsella bursa-pastoris (AY929829), and the cox2 sequences (GenBank accession Nos. MW147150 and MW147151) were 100% (567/567 nucleotides) identical to that of A. koreana from C. bursa-pastoris (AY927048). Based on the concatenated ITS and cox2 sequences, Maximum Likelihood and Bayesian analysis showed that pathogen from C. sativa with the reference isolate of A. koreana (ex C. bursa-pastoris) with high bootstrap support values and maximum posterior probability (100 ML BS and 1.00 BPP, respectively). For pathogenicity, sporangia collected from the infected leaves were suspended in sterile water at 4°C for 2 hours to improve zoospore release, and the zoospore suspension obtained from sporangial suspension (1×105 sporangia/ml) was inoculated to the lower surface of six healthy potted plants. Three non-inoculated plants were served as controls. Each plant was kept in a separate plastic humid chamber in a greenhouse with 25°C and 80% humidity for 15 days. Typical symptoms of white rust pustules developed on the inoculated plants were identical to that observed on the originally infected leaves. Control plants remained symptomless.. Based on morphological characteristics, molecular data, as well as pathogenicity tests, the pathogen on C. sativa was identified as Albugo koreana. A. koreana aslo is reported only on C. bursa-pastoris in Korea (Choi et al. 2007; Farr and Rossman 2020). To our knowledge, this is the first record of white rust disease caused by A. koreana on C. sativa, and the species is new to China. This report represents a new host plant association and a new geographical expansion for this species, presenting a potential threat to camelina production in northwest China.
PubMed: 33496607
DOI: 10.1094/PDIS-11-20-2332-PDN -
Aging Cell Feb 2021Stem cell transplantation has been generally considered as promising therapeutics in preserving or recovering functions of lost, damaged, or aging tissues....
Stem cell transplantation has been generally considered as promising therapeutics in preserving or recovering functions of lost, damaged, or aging tissues. Transplantation of primordial germ cells (PGCs) or oogonia stem cells (OSCs) can reconstitute ovarian functions that yet sustain for only short period of time, limiting potential application of stem cells in preservation of fertility and endocrine function. Here, we show that mTOR inhibition by INK128 extends the follicular and endocrine functions of the reconstituted ovaries in aging and premature aging mice following transplantation of PGCs/OSCs. Follicular development and endocrine functions of the reconstituted ovaries by transplanting PGCs into kidney capsule of the recipient mice were maintained by INK128 treatment for more than 12 weeks, in contrast to the controls for only about 4 weeks without receiving the mTOR inhibitors. Comparatively, rapamycin also can prolong the ovarian functions but for limited time. Furthermore, our data reveal that INK128 promotes mitochondrial function in addition to its known function in suppression of immune response and inflammation. Taken together, germline stem cell transplantation in combination with mTOR inhibition by INK128 improves and extends the reconstituted ovarian and endocrine functions in reproductive aging and premature aging mice.
Topics: Aging; Aging, Premature; Animals; Benzoxazoles; Female; Germ Cells; Mice; Mice, Inbred C57BL; Mice, Inbred ICR; Mice, Inbred NOD; Mice, Knockout; Mice, SCID; Ovary; Pyrimidines; TOR Serine-Threonine Kinases
PubMed: 33448083
DOI: 10.1111/acel.13304 -
Ecotoxicology and Environmental Safety Mar 2021This study aimed to explore the toxicity of environmental residues of graphene oxide nanoparticles (GONPs) to reproduction of Lepidopteron insects using both ovary cell...
This study aimed to explore the toxicity of environmental residues of graphene oxide nanoparticles (GONPs) to reproduction of Lepidopteron insects using both ovary cell line (BmN) and individual female Bombyx mori as the research subjects. The results showed that GONPs dose dependently affect BmN cells. At higher concentrations (>25 mg/L), GONPs led to oxidative stress, ROS accumulation and DNA damage in BmN cells and significantly reduced their survival rate (p ≤ 0.05). Moreover, feeding female B. mori larvae with mulberry leaves treated with 25 mg/L GONPs significantly decreased their gonadosomatic index (GSI) by 40.84%, and increased oxidation levels and antioxidant enzyme activity in silkworm ovary tissues. Pathological analysis found that exposure to GONPs decreased the numbers of both oogonia and oocytes in ovarian tissues, increased the formation of peroxisome and vacuoles in follicle cells, reduced the transcription of genes (Vg, Ovo, Sxl-s, Sxl-l, and Otu) related to ovarian development in B. mori by 0.61, 0.65, 0.75, 0.72, and 0.42-fold, respectively, and lowered the amount of spawning by 52.25%. Overall, these results revealed that GONPs exposure is toxic to the reproduction of B. mori. The underlying mechanism is that oxidative stress due to GONPs causes oxidative damage to DNA, damages ovarian tissues, as well as hinders B. mori development and spawning. Thus, this study provides important experimental data for safety evaluation of reproductive toxicity due to GONPs exposure.
Topics: Animals; Bombyx; Cell Line; DNA Damage; Female; Graphite; Male; Nanoparticles; Oocytes; Oxidative Stress; Reactive Oxygen Species; Reproduction
PubMed: 33421719
DOI: 10.1016/j.ecoenv.2020.111888 -
Plant Disease Jan 2021Italian ryegrass ( Lam.) and perennial ryegrass ( L.) are important for hay fields and grazing lands across Japan, with nearly 70,000 ha production, the largest share in...
Italian ryegrass ( Lam.) and perennial ryegrass ( L.) are important for hay fields and grazing lands across Japan, with nearly 70,000 ha production, the largest share in forage grass cultivation. In August 2018, damping off of seedlings of both species was observed about 2wk after seeding in Tochigi Prefecture, central region of Japan. Roots were brown and decayed drastically with browning of basal stem. Nearly 90% of the row seedling stands were eradicated in some fields, especially ones seeded from August to early September, when the soil and air temperatures were around 25-30 ˚C. Six Pythium-like isolates were obtained by isolation from surface-sterilized diseased hypocotyls (1-2cm) placed on water agar. Six isolates were purified as single hyphal tips and deposited at the NARO genebank (https://www.gene.affrc.go.jp/index_en.php), with accession no. MAFF101946-101951. Two of them, MAFF101946 and 101948 were used for detailed study. The isolates were grown in the dark on clarified V8 juice agar for 10 days to produce oogonia. The oogonia of MAFF101946 were globose, colorless, smooth, 21 to 30 µm in size, and had 1(- 2) antheridia. Oospores were mostly aplerotic, and oogonia walls were 1.1 to 2.3 µm thick. The oogonia of MAFF101948 were globose, colorless, smooth, 19 to 27 µm in size, and had 2-5 antheridia. Oospores were mostly plerotic, and oogonia walls were 1.7 to 4.2 µm thick. The morphology of the MAFF101946 matched that of (Edson) Fitzp.(abbr. PA) and the MAFF101948 matched Drechsler (abbr. PP) (Van der Plaats-Niterink, 1981). DNA sequences of (Robideau et al, 2011) and rDNA-ITS regions (White et al,1990) of each isolate were analyzed. The sequences of the MAFF101946 and 101948 (GenBank Accession No. LC548774 and LC548775) matched 100% (680/680 bp) with that of PA (HQ708486) and PP (HQ708781), respectively. The rDNA-ITS sequence of the MAFF101946, LC592700, matched PA (772/777 bp; HQ643439), and the MAFF101948 (LC592701) matched PP (HQ643740), with 99% similarity (764/773 bp). The optimal growth temperature was 35 ˚C for both. Their pathogenicity was confirmed by seeding two Italian (cv. Inazuma and Minamiaoba) and perennial (cv. Yatsuyutaka and Natsugoshi-pere) ryegrasses cultivars in cell trays containing commercial potting mixture inoculated with the isolates. Barley grains autoclaved with a half volume of water and incubated with each isolate at 25 ˚C for about 2 wk were added to inoculate the potting mixture (5%, v/v). Separate trays were used for each isolate to avoid cross-contamination, sown with 60 seeds were sown per cv. and the trays were placed in a light thermostat chamber under the daily cycle of 16 hr light at 30 ˚C and 8 hr dark at 25 ˚C. About 3 wk later, seedlings on the inoculated soil exhibited the symptoms, but not in control (no inoculum) plots. Both inoculated organisms were re-isolated from the diseased plants to confirm their pathogenicity. PA was more aggressive with grater percent damping off compared to PP. Both species are known as pathogens of diverse plants including grasses and legumes (Abad et al, 1994; Ao et al, 2018), but to our knowledge, this is the first report of seedling damping off caused by these Pythium species in forage ryegrass in Japan. With the increased duration of hot, humid condition across temperate regions due to global warming, the damping off may become a problem in hay fields and pasture and resistance breeding for these pathogens may be needed.
PubMed: 33393358
DOI: 10.1094/PDIS-09-20-1986-PDN -
Genes, Chromosomes & Cancer Jun 2021Teratomas are the most common tumors in the ovary during childhood. Previous studies suggested that they may be derived from germ cells at any developmental stage from...
Teratomas are the most common tumors in the ovary during childhood. Previous studies suggested that they may be derived from germ cells at any developmental stage from premeiotic oogonia through meiotic oocytes to post-meiotic ova. The majority of mature teratomas reveal normal karyotypes and immature teratomas show higher frequency of chromosomal abnormalities. We analyzed fresh tissue samples from 25 primary ovarian teratomas and three extraovarian deposits using whole genome single nucleotide polymorphism (SNP) array and karyotype. SNP array detected five patterns of copy neutral loss of heterozygosity (CN-LOH): failure of meiosis I (type I) in 12 tumors, failure of meiosis II (type II) in six tumors, endoreduplication of a haploid ovum (type III) in two tumors, premeiotic error (type IV) in four tumors, and both meiotic I and meiotic II errors in one tumor (type V). Three tumors with type I error had a single chromosome showing meiotic II error, and two tumors with type II error had a single chromosome showing premature sister-chromatid separation in meiosis I. Lack of recombination in multiple chromosomes in meiosis I were common, chromosomes 17, 7, 8, 21, and 22 were most commonly involved. Abnormal karyotypes were observed in four teratomas including +3, del(3q), +7, +8, +12, and i(18q). The extraovarian deposits revealed the same CN-LOH pattern as the primary teratoma. In summary, SNP array reveals the origin of ovarian teratoma and we propose a new mechanism that consecutive meiotic I and II errors occur frequently in ovarian teratomas.
Topics: Abnormal Karyotype; Adolescent; Child; Chromosomes; Female; Humans; Loss of Heterozygosity; Meiosis; Ovarian Neoplasms; Polymorphism, Single Nucleotide; Recombination, Genetic; Teratoma
PubMed: 33377559
DOI: 10.1002/gcc.22934 -
Zoological Studies 2020Sex differentiation during gonadal development is diversified among anuran amphibian species. In this study, the anuran experimental species was examined. The pattern...
Sex differentiation during gonadal development is diversified among anuran amphibian species. In this study, the anuran experimental species was examined. The pattern of gonadal sex differentiation was observed by morphological and histological approaches. The gonad was observed morphologically at Gosner stage 33, while distinct testis and ovary were evident from 3-4 weeks after metamorphosis ended. Histological analysis showed that genital ridge formation began at stage 25 and ovarian differentiation began at stage 36. The developing ovary appeared with numerous primary oogonia, which developed into oocytes, while the medulla regressed to form an ovarian cavity. During metamorphosis, only an ovary was observed. Testicular differentiation seemed to begin later, during the first week after metamorphosis, and occurred via an intersex condition. The intersex gonads contained developing testicular tissue with both normal and atretic oocytes. The fully developed testis was first identified at 6 weeks after metamorphosis. Comparing the times of gonadal differentiation and somatic development revealed that the ovary exhibited a basic rate of differentiation while the testis exhibited a retarded one. These results establish that males of this species develop later than do females, and the testis develops through an intersex gonad, as is evident from its seminiferous cord formation, the presence of testis-ova, and atretic oocytes in the tissue. Thus, the pattern of gonadal sex differentiation in is an undifferentiated type, in which only female gonads are observed during metamorphosis and intersex and male gonads are observed later. These results are crucial for further research on the sexual development of anurans.
PubMed: 33363623
DOI: 10.6620/ZS.2020.59-51 -
Biochemical and Biophysical Research... Jan 2021No effective cryopreservation technique exists for fish eggs and embryos; thus, the cryopreservation of germ cells (spermatogonia or oogonia) and subsequent generation...
Production of juvenile masu salmon (Oncorhynchus masou) from spermatogonia-derived sperm and oogonia-derived eggs via intraperitoneal transplantation of immature germ cells.
No effective cryopreservation technique exists for fish eggs and embryos; thus, the cryopreservation of germ cells (spermatogonia or oogonia) and subsequent generation of eggs and sperm would be an alternative solution for the long-term preservation of piscine genetic resources. Nevertheless, in our previous study using rainbow trout, we showed that recipients transplanted with XY spermatogonia or XX oogonia produced unnatural sex-biased F1 offspring. To overcome these obstacles, we transplanted immature germ cells (XX oogonia or XY spermatogonia; frozen for 33 days) into the body cavities of triploid hatchlings, and the transplanted germ cells possessed a high capacity for differentiating into eggs and sperm in the ovaries and testes of recipients. Approximately 30% of triploid recipients receiving frozen germ cells generated normal salmon that displayed the donor-derived black body color phenotype, although all triploid salmon not receiving transplants were functionally sterile. Furthermore, F1 offspring obtained from insemination of the oogonia-derived eggs and spermatogonia-derived sperm show a normal sex ratio of 1:1 (female:male). Thus, this method presented a critical technique for practical conservation projects for other teleost fish species and masu salmon.
Topics: Aging; Animals; Cell Differentiation; Conservation of Natural Resources; Cryopreservation; Female; Germ Cells; Male; Oncorhynchus; Oogonia; Ovum; Sex Ratio; Spermatogonia; Spermatozoa; Triploidy
PubMed: 33340766
DOI: 10.1016/j.bbrc.2020.12.021 -
Plant Disease Dec 2020During a 2019-2020 survey for plant pathogenic oomycetes in Nanjing, China, severe foliage blight and dieback were observed on approximately 20 Rhododendron pulchrum...
During a 2019-2020 survey for plant pathogenic oomycetes in Nanjing, China, severe foliage blight and dieback were observed on approximately 20 Rhododendron pulchrum plants at three public parks and gardens. Approximately 25% of leaves and shoots were affected. Symptoms included brown to black lesions on leaves and stems, dieback of shoot tips, and wilting. Diseased tissues were collected from a five-year-old shrub with typical disease symptoms at Xuanwuhu Park. They were cut into 10×10 mm2 squares, immersed in 70% ethanol for 30 sec, and placed onto fresh clarified V8 juice agar (cV8A) containing pimaricin, ampicillin, rifampicin, and pentachloronitrobenzene. Phytophthora-like hypae were transferred to new cV8A plates daily. A total of five isolates were obtained after five days of incubation at 25°C. After approximately 20 days, all isolates were identical in morphological traits including semi-papillate sporangia and gametangia (homothallic). Thirty sporangia of a representative isolate Ppi were randomly selected and examined. They were mostly ovoid and sometimes obpyriform, averaging 41.0 ± 3.9 × 24.8 ± 3.2 µm. Antheridia of 30 randomly selected gametangia were paragynous, averaging 16.7 ± 0.7 × 12.4 ± 1.5 µm. Average diameters of oogonia and plerotic oospores were 29.2 ± 0.3 µm and 26.4 ± 1.6 µm, respectively. Chlamydospores were not observed. The above morphological traits suggested the causal agent belonging to the "P. citricola-complex". Isolate Ppi was subjected to sequencing of the rDNA internal transcribed spacer (ITS) region and the ras-related GTP-binding protein 1 (Ypt1) gene. ITS sequence of Ppi (GenBank ACN. MT672594) has 100% identity to that of P. pini (MG865565). It has a 3-nt difference from the ITS sequences of P. acerina (MG518642) and P. citricola (MG865475) and a 4-nt difference from that of P. plurivora (FJ665225). Ypt1 sequence of Ppi (MT680000) has 100% identity to that of P. pini (MK058416). Pathogenicity of Ppi on R. pulchrum was tested using both detached-leaf and whole-plant assays. In the former assay, each of six asymptomatic leaves was symmetrically wounded at both sides using a sterile inoculation needle. A 5×5 mm2 Ppi-colonized cV8A plug was placed on each wound of five leaves. Sterile agar plugs were used for a control leaf. All six leaves were placed on a wet filter paper in a closed container at 25°C. This assay was repeated twice. On the fifth day, all inoculated leaves had necrotic tissues around the wounds, while the control leaves remained asymptomatic. In the whole-plant assay, 20-inch-tall plants were used. Five attached leaves and the twig base of each plant were wounded. A control plant was inoculated in the same manner above, while sterile agar plugs were used. Each plant was covered with a plastic bag and maintained at 25°C. Wet cotton balls were placed in the bags to maintain humidity. After two days, the bag containing cotton balls was removed. This assay was repeated three times. After two weeks, all three inoculated plants in the three replicated trials had severe foliage blight and dieback, whereas control plants remained healthy. Phytophthora isolates recovered from artificially inoculated tissues were identical to isolate Ppi in morphological characters. Rhododendron diseases caused by P. pini were reported in the USA and Finland . This is the first report of P. pini causing foliage blight and dieback on R. pulchrum, an important nursery and landscape plant in China. Additional surveys are ongoing to determine the distribution of this pathogen in Nanjing. Management programs are under development to contain the spread of P. pini and treat diseased plants.
PubMed: 33267642
DOI: 10.1094/PDIS-07-20-1422-PDN -
Plant Disease Nov 2020Sugar beet (Beta vulgaris L.) is a globally important crop for sugar. In May 2019, sugar beet seedlings were observed with wilting, lodging and a few were dead in...
Sugar beet (Beta vulgaris L.) is a globally important crop for sugar. In May 2019, sugar beet seedlings were observed with wilting, lodging and a few were dead in Glendive (46.970170, -104.838204), Montana. Symptoms appeared near the soil line as the stem (hypocotyl) turned dark brown to black with characteristic thread-like infections which resembled Pythium damping-off. It affected approximately 10% of the growing seedlings. Diseased sugar beet root tissues were excised with a sterile scalpel and small pieces (10 mm²) were surface sterilized with 70 % ethanol for 30 seconds, rinsed twice with autoclaved water, air-dried and transferred to potato dextrose agar (PDA) media amended with pimaricin-vancomycin-PCNB (Conway, 1985). Four plates were incubated at 25° C in the dark (Masago et al., 1977) and two weeks later white, dense colony was observed (Zhang et al., 2018). The terminal smooth, globose oogonia (average 18.5 µm in diameter) and antheridia (average 14.5 × 9.5 µm) extended below the oogonium were observed via VWR N. A. 0.30 microscope. The morphological features of the four isolates were consistent with Pythium ultimum Trow (Watanabe, 2002). Genomic DNAs (NORGEN BIOTEK CORP, Fungi DNA Isolation Kit #26200) of four isolates were used for polymerase chain reaction (PCR) with the ITS6-ITS7 primers (Taheri et al., 2017). Subsequently, PCR products were flushed by E.Z.N.A ®Cycle Pure Kit, OMEGA and four samples were sent for Sanger sequencing to GenScript (GenScript, Piscataway, NJ). The sequences were identical and submitted to GenBank, NCBI (accession no. MN398593). The NCBI Blast analysis showed 100% sequence homology to Pythium ultimum with the following GenBank accessions; KF181451.1, KF181449.1 and AY598657.2. Pathogenicity test was done on sugar beet with the same isolates in the greenhouse. Two week old, pythium culture was mixed with vermiculite and perlite mixer (PRO-MIX FLX) in the plastic trays (24´´ x 15´´× 3˝), (22 °C, 75% Relaive Humidity). Sterile water (500 ml/each tray) was added in the mixer to provide sufficient moisture. Twenty seeds of cv. Hilleshog 4302 were sown in the tray, and the trays were replicated thrice with inoculated and mock treatments. Plants were watered as needed to maintain adequate soil moisture conducive for plant growth and disease development. Seven days after sowing, 50% and 100% germination was observed in the inoculated and control treatments, respectively. At the beginning of the second week, 30% post-emergence damping-off was observed in the inoculated treatments. Diseased seedlings were gently pulled out from the pots where similar symptoms were observed in the sugar beet seedlings as described previously. No incidence of disease was observed in mock-treated seedlings. Consistent reisolation of Pythium ultimum was morphologically and molecularly confirmed from the diseased seedlings, thus fulfilling Koch's postulates. Pythium spp identification is prerequisite to develop effective management of pre and post-emergence damping-off. Pythium ultimum was previously reported in Nebraska to cause sugar beet seed rot and pre-emergence damping-off (Harvenson 2006). To our knowledge, this is the first report of Pythium ultimum causing damping-off on sugar beet in the Sidney factory district in Montana.
PubMed: 33225812
DOI: 10.1094/PDIS-10-20-2108-PDN