作者：
Chen, X. Z.;Yang, Q.;Wan, Z.;Zhou, G. Y.;Liu, J. A.
期刊：
PLANT DISEASE,2021年105(8):2255 ISSN：0191-2917
通讯作者：
Chen, Xing Zhou;Yang, Quan;Wan, Zhi;Zhou, Guo Ying;Liu, Jun Ang
作者机构：
[Chen, X. Z.; Liu, J. A.; Yang, Q.; Wan, Z.; Zhou, G. Y.] Cent South Univ Forestry & Technol, Hunan Prov Key Lab Control Forest Dis & Pests, Changsha 410004, Peoples R China.
通讯机构：
[J. A. Liu] H;Hunan Provincial Key Laboratory for Control of Forest Diseases and Pests, Central South University of Forestry and Technology, Changsha 410004, P.R. China
关键词：
fungi;trees;forest;epidemiology;disease development and spread
摘要：
Dalbergia odorifera T. Chen (family Fabaceae) is one of four prized species of mahogany plant in China. In June 2017, an investigation of the condition of anthracnose was carried out on apporximately 333 hectares of D. odorifera plantations in Haikou City, Hainan Province (110.19°E, 20.03°N). Approximately 40% of D. odorifera plants had disease symptoms. Lesions on leaves were brown to grayish-white containing black dots and dark-brown borders, occasionally surrounded by a yellowish-green halo. Leaf spots generally occurred along the edge of the leaf. Severely infected leaves became withered and died. Hyphal growth was recovered from symptomatic leaf tissue, surface-sterilized with a 75% ethanol solution for 30s, rinsed with sterile distilled water, plated on potato dextrose agar (PDA), and incubated at 26°C in the dark. The representative isolate JXHTC19 was recovered by transferring a hyphal tip to a fresh PDA plate to obtain a pure culture. Fungal colonies had white aerial mycelium initially, turning pale gray after 3 days. At 7 days, colonies had a cottony appearance ranging from white to dark gray with orange masses of conidia. The colony surface was slimy and aerial mycelium was sparse. Isolates displayed single-celled, cylindrical, hyaline conidia that were rounded at both ends, and were 9.7 - 16.4 μm long (avg. 13.5 μm) × 3.6 - 6.2 μm wide (vg. 4.8 μm) (n = 100). To further identify the fungus, genomic DNA was extracted from single conidial cultures of JXHTC19. The rDNA internal transcribed spacer (ITS) region, glutamine synthetase (GS) gene, partial sequence of glyceraldeyde-3-phosphate dehydrogenase-like (GAPDH) gene, actin (ACT) gene, and beta-tubulin (TUB2) gene were amplified using the primer pairs ITS4/ITS5, GS-F/GS-R, GDF1/GDR1, ACT-512F/ACT-783R, and TUB2-T1/Bt-2b (Weir et al 2012), respectively. The results showed that the ITS, GS, GAPDH, ACT and TUB2 genes of the target strain (JXHTC19) have 100%, 95%, 100%, 97% and 98% sequence homology with C. brevisporum, respectively. The sequences obtained were deposited in GenBank (MF993572, MN737615, MN737614, MG515612, and MG515615[LJ1]). All five sequences were analyzed together with representative sequences from type or ex-type specimens of the Colletotrichum genus (Yang et al. 2011, Weir et al. 2012) and a phylogenetic tree was generated via the neighbor-joining method using MEGA6. The tree placed the isolate in the same group as C. brevisporum. Thus, both morphological and molecular characteristics identified the pathogen as C. brevisporum. To verify Koch's postulates, two-year-old leaves of healthy potted D. odorifera plants (n = 6) were inoculated with a spore suspensions of JXHTC19 that contained 105 conidia/ml. Plants were sprayed with water to serve as mock-inoculated controls [LJ2](Garibaldi et al, 2020). Six plants per treatment were used in each test. The test was repeated once.Plants were incubated in moist chambers at 26°C and monitored daily for symptom development. After five days, eleven of twelve isolates [LJ3]caused lesions on all inoculated plants, whereas no symptoms developed on the mock-inoculated controls. Koch's postulates were fulfilled by reisolating the same fungus and verifying its colony and morphological characters as C. brevisporum. To our knowledge, this is the first report of this species causing anthracnose of D. odorifera in China. Corresponding measures must be adopted to manage this disease such as reducing the planting density of D. odorifera and increasing the species diversity of undergrowth vegetation. These results could help develop better monitoring and management practices for this disease.
作者机构：
[刘昌霖; 周国英; 肖柏; 刘君昂] Hunan Provincial Key Laboratory for Control of Forest Diseases and Pests, Key Laboratory for Non-Wood Forest Cultination and Conseration of Ministry of Education, Central South University of Forestry and Technology, Changsha, 410004, China
通讯机构：
Hunan Provincial Key Laboratory for Control of Forest Diseases and Pests, Key Laboratory for Non-Wood Forest Cultination and Conseration of Ministry of Education, Central South University of Forestry and Technology, Changsha, China
摘要：
Tea-oil tree (Camellia oleifera) is a unique edible-oil tree in China, and anthracnose occurs in wherever it is cultivated, causing great economic losses each year. We have previously identified the Ascomycete fungus Colletotrichum fructicola as the major pathogen of anthracnose in Ca. oleifera. The purpose of this study was to characterize the biological function of Snf1 protein, a key component of the AMPK (AMP-activated protein kinase) pathway, for the molecular pathogenic-mechanisms of C. fructicola. We characterized CfSnf1 as the homolog of Saccharomyces cerevisiae Snf1. Targeted CfSNF1 gene deletion revealed that CfSnf1 is involved in the utilization of specific carbon sources, conidiation, and stress responses. We further found that the ΔCfSnf1 mutant was not pathogenic to Ca. oleifera, resulting from its defect in appressorium formation. In addition, we provided evidence showing crosstalk between the AMPK and the cAMP/PKA pathways for the first time in filamentous fungi. This study indicate that CfSnf1 is a critical factor in the development and pathogenicity of C. fructicola and, therefore, a potential fungicide target for anthracnose control.
关键词：
fungal rust disease, plant crops, sua wood, annual ryegrass, maize, peanut, spring onion, biological control
摘要：
Larvae of a gall midge were found feeding on the fungal rust Maravalia pterocarpi (Pucciniomycetes: Pucciniales: Chaconiaceae) infesting the economically important sua tree Dalbergia tonkinensis (Fabaceae) on Hainan Island, China. The adults, pupae and larvae were collected, their morphology was studied and a segment of the Cytochrome Oxidase unit I (COI) mitochondrial gene was sequenced. The gall midge proved to be a species new to science that belongs to the genus Mycodiplosis (Diptera: Cecdiomyiidae). Comparison of the sequence to published Cecdiomyiidae sequences revealed that, despite being undescribed and unnamed, it was previously found in east and south-east Asia to feed on several rust species: Puccinia coronata (Pucciniomycetes: Pucciniales: Pucciniaceae) that develops on Lolium multiflorum (Poaceae), Puccinia sp. on Zea mays (Poaceae), Puccinia arachidis on Arachis hypogaea (Fabaceae) and Puccinia allii on Allium fistulosum (Amaryllidaceae). The new species is described and named here Mycodiplosis puccinivora Jiao, Bu & Kolesik. It occurs in China, Japan, Thailand, Bangladesh and possibly Malaysia and Australia. In Hainan it has four to five generations per year.
作者机构：
[李河; 李司政; 王悦辰; 刘君昂; 徐建平; 周国英] Key Laboratory for Non-Wood Forest Cultivation and Conservation of Ministry of Education, Central South University of Forestry and Technology, Changsha, 410004, China
通讯机构：
Key Laboratory for Non-Wood Forest Cultivation and Conservation of Ministry of Education, Central South University of Forestry and Technology, Changsha, China
摘要：
<jats:title>Abstract</jats:title><jats:p>The major facilitator superfamily (MFS) is one of the largest membrane‐protein families. To investigate the role of MFS proteins in the fungal plant anthracnose pathogen <jats:italic>Colletotrichum fructicola</jats:italic>, the <jats:italic>CfMFS1</jats:italic> gene was deleted. This resulted in reduced mycelial growth, conidial yield and decreased virulence on tea oil camellia leaves. In addition, ∆<jats:italic>Cfmfs1</jats:italic> showed increased sensitivity to osmotic stress and to a cell‐wall stressor. Further analysis revealed that CfMfs1 is required for conidial penetration and appressorial turgor pressure, both important for fungal pathogen invasion. Confocal fluorescence microscopy showed that CfMfs1 is localized to membranes of both hyphae and conidia, suggesting that it may be a membrane transporter. Our study provides evidence that CfMfs1 has a role in conidiation, sugar transport, stress response, conidial penetration, appressorial turgor pressure and virulence against tea oil camellia.</jats:p>
通讯机构：
Central South University of Forestry and Technology, Key Laboratory of Cultivation and Protection for Non-Wood Forest Trees of Ministry of Education, Hunan Provincial Key Laboratory for Control of Forest Diseases and Pests, Changsha, China
