蓝光诱导的胶孢炭疽菌(Colletotrichum gloeosporioides)类胡萝卜素积累

胶孢炭疽菌(Colletotrichumgloeosporioides)为一种丝状真菌,蓝光照射可诱导类胡萝卜素的积累。光镜下观察表明,蓝光可诱导胶孢炭疽菌菌丝积累色素颗粒,而黑暗和红光处理却无此现象。类胡萝卜素的积累受蓝光光照强度的影响。28℃且蓝光为6.5μmol.m-2.s-1时,类胡萝卜素积累量可随光照时间延长呈增长趋势,在第5天达到最高峰为71.8μg/g FW,随后含量下降。此外,胶孢炭疽菌在黑暗中预培养的时间也影响蓝光的诱导反应。     

Colletotrichum fructicola and C. siamense are involved in chilli anthracnose in India

Chilli anthracnose is a major problem in India and worldwide. In this study, we investigated the phylogenetic relationships of 52 fungal isolates associated with chilli anthracnose in southern India. All the 52 isolates were sequenced for partial ITS/5.8S rRNA and glyceraldehyde-3-phosphate dehydrogenase (gapdh) genes and showed affinities with Colletotrichum siamense and C. fructicola within Colletotrichum. gloeosporioides species complex. Further, a reduced subset of 17 selected isolates was made and in a maximum parsimony analysis of a multigene data-set including partial ITS/5.8S rRNA, actin (act), calmodulin (cal), chitin synthase (chs1), gapdh and β-tubulin (tub2) gene sequence data, these fungal isolates clustered with the type strain of C. fructicola, except for strain MTCC 3439 that showed phylogenetic affinities with C. siamense. The pathogenicity tests involving two representative isolates: UASB-Cg-14 and MTCC 3439, confirmed the involvement of C. fructicola and C. siamense in the development of disease symptoms on fresh chilli fruits. This is the first report of the association of C. fructicola and C. siamense in causing chilli anthracnose in India.     

Assessment of potential antagonists for anthracnose (Colletotrichum gloeosporioides) disease of mango (Mangifera indica L.) in North Western Ethiopia (Pawe)

Mango (Mangifera indica L.) is considered as one of the most popular fruits among millions of people in the tropical area and increasingly in the developed countries. Anthracnose, caused by the fungus Colletotrichum gloeosporioides, is the most important pre- and post-harvest disease of mango. The objective of this research was to evaluate the prevalence of different promising antagonistic Trichoderma and Bacillus spp. on phyloplane of mango in Ethiopia and to evaluate their antagonistic potential against the pathogen. A total of 19 mango fields were surveyed and anthracnose affected all fields. Culture studies on potato dextrose agar for evaluation of antibiosis activity of Trichoderma spp. and Bacillus spp. revealed that they have inhibitory and lytic effect on C. gloeosporioides, which is an indication of their potential biocontrol agent for management of mango anthracnose as an alternative to chemical control. Significant differences (p?<?0.05) were observed among Bacillus isolates in causing lysis of pathogen mycelium, when inoculated on actively growing colony of C. gloeosporioides. Maximum reduction in growth rate of pathogen was observed with Bacillus spp. (B50), which restricted the growth to 2.7?mm compared to 8.3?mm in the control with 67.5% efficacies. There were similar effects (p?<?0.05) among Trichoderma spp. in formation of inhibition zones and lysis by varying degrees up to 59.7% efficacies in reducing linear growth of the pathogen in dual culture.     

Inheritance of resistance in water yam (Dioscorea alata) to anthracnose (Colletotrichum gloeosporioides)

Colletotrichum gloeosporioides causes anthracnose, the most severe foliar disease of field-grown water yam (Dioscorea alata). The inheritance of resistance to a moderately virulent (FGS) strain of the pathogen was investigated in crosses between tetraploid D. alata genotypes: TDa 95/00328 (resistant)×TDa 95–310 (susceptible) (cross A), and TDa 85/00257 (resistant)×TDa 92–2 (susceptible) (cross B). Segregation of F₁ progeny fitted genetic ratios of 3:1, 5:1 (crosses A and B) and 7:1 (cross A) resistant:susceptible when inoculated with the FGS strain, indicating that resistance is dominantly inherited and suggesting that more than one gene controls the inheritance of resistance to this strain in the accessions studied. When parental and progeny lines of cross A were inoculated with an aggressive (SGG) strain of the pathogen, all plants expressed a susceptible phenotype, indicating strain-specific resistance in TDa 95/00328. Screening of 20 cultivars/landraces confirmed the high susceptibility of D. alata accessions to the SGG strain and revealed the presence of apparent strain non-specific resistance in TDa 85/00257. TDa 85/00257 and TDa 87/01091 which were resistant to the SGG strain, will be useful both as sources of resistance and in the development of a host differential series for D. alata. Received: 15 May 2000 / Accepted: 18 October 2000     

Detection and differentiation of Colletotrichum gloeosporioides isolates using PCR

An oligonucleotide primer (CgInt), synthesised from the variable internally transcribed spacer (ITS) 1 region of ribosomal DNA (rDNA) of Collectotrichum gloeosporioides was used for PCR with primer ITS4 (from a conserved sequence of the rDNA) to amplify a 450-bp fragment from the 25 C. gloeosporioides isolates tested. This specific fragment was amplified from as little as 10 fg of fungal DNA. A similar sized fragment was amplified from DNA extracted from C. gloeosporioides-infected tomato tissue. RAPD analysis divided 39 C. gloeosporioides isolates into more than 12 groups linked to host source and geographic origin. Based on the results obtained, the potential of PCR for detection and differentiation of C. gloeosporioides is discussed.     

Purification and characterization of an endochitinase produced by Colletotrichum gloeosporioides

The phytopathogenic fungus Colletotrichum gloeosporioides was analyzed for chitinase activity, the best production occurring at the fourth day. A 43 kDa endochitinase with specific activity of 413 U microg(-1) protein was purified corresponding to a 75% yield. The optima of temperature and pH for the enzyme were 50 degrees C and pH 7.0, respectively. The enzyme showed a high stability at 50 degrees C and pH 7.0. Values of pH from 5.0 up to 7.0 gave, at least, 50% of maximum activity, suggesting a biotechnological application. Further studies are in progress to determine the possible use of this endochitinase in biological control.     

Biological control of anthracnose (Colletotrichum gloeosporioides) in yam by Streptomyces sp.MJM5763

Aim: To find a suitable biocontrol agent for yam anthracnose caused by Colletotrichum gloeosporioides. Methods and Results: An actinobacterial strain, MJM5763, showing strong antifungal activity, multiple biocontrol and plant growth‐promoting traits was isolated from a yam cultivation field in Yeoju, South Korea. Based on morphological and physiological characteristics and analysis of the 16S rDNA sequence, strain MJM5763 was identified as a novel strain of Streptomyces and was designated as Streptomyces sp. MJM5763. Treatment with MJM5763 and the crude culture filtrate extract (CCFE) was effective in suppressing anthracnose in detached yam leaves in vitro and reduced incidence and severity of anthracnose in yam plants under greenhouse conditions. The CCFE treatment was the most effective of all the treatments and reduced the anthracnose severity by 85–88% and the incidence by 79–81%, 90 days after inoculation with the pathogen. CCFE treatment was also effective under field conditions and showed a reduction of 86 and 75% of anthracnose severity and incidence, respectively. Conclusion: Streptomyces sp. strain MJM5763 was effective in biocontrolling anthracnose in yam caused by C. gloeosporioides. Significance and Impact of the Study: Streptomyces sp. MJM5763 is a potential alternative to chemical fungicides for reducing yield losses to anthracnose in yam.     

海南和两广地区柱花草炭疽菌遗传多态性的RAPD分析

利用8个随机引物对来自海南、广东和广西的114个柱花草胶孢炭疽菌（Colletotrichum gloeosporioides）的菌株进行了随机扩增多态性DNA（RAPD）分析,扩增谱带大小0．2-3．0kb。8个随机引物中以CW38114扩增的谱带重现性和稳定性最好,共扩增出786条谱带,其中多态性谱带558条。供试菌株扩增图谱在260-650bp处有3条明显的共同特征谱带,在650—3000bp之间的谱带显示较大的多态性差异。聚类结果表明：供试菌株主要分为四大遗传类型。其中第Ⅰ类和第Ⅲ类有两个亚类;三省区的菌株遗传多态性丰富程度依次为海南〉广西〉广东,并表现出地区性分布差异。研究结果还表明柱花草炭疽菌株表现出一定程度的专化寄生性。     

Rapid Screening Method of Cassava Cultivars for Resistance to Colletotrichum gloeosporioides f.sp. manihotis

An in vitro method for assessing cassava anthracnose disease (CAD) resistance was developed as a preliminary screen to a CAD-resistant breeding programme. Potato dextrose agar (PDA) media was amended by extracts from the stem cortex of 10 cassava cultivars (30001; 30572, 30211, 88/02549, 88/00695, 88/01336, 91/00344, 91/00313, 91/00684 and 91/00475), and assayed for efficacy of inhibition of the growth of Colletotrichum gloeosporioides f. sp. manihotis isolates (05FCN, 10FCN, 12FCN, and 18FCN). Morphological and physiological data indicated that there was a significant difference (P ≤ 0.05), in mycelial growth, spore germination and sporulation among the four isolates on PDA amended with cassava stem extracts. Extracts from cassava cultivars 30211, 91/00684 and 91/00313 showed higher inhibition of germ tube development, mycelial growth and sporulation of the fungal isolates, whereas cultivars 88/02549 and 88/01336 showed the least inhibition. The 10 cultivars were further tested in both greenhouse and field conditions, under disease pressure for two planting seasons, to corroborate resistance to the fungus as observed in vitro . Greenhouse and field trials with the 10 cassava cultivars showed a significant difference ( P  ≤ 0.05) in CAD resistance. Cultivars 88/02549 and 88/01336 were highly CAD-susceptible, as shown in the in vitro assays and confirmed in the greenhouse and field tests. The other eight cultivars were either resistant (30211, 91/00684), or moderately resistant (30572, 88/00695, 91/00475, 91/00344, 30001 and 91/00313) to CAD. The study shows that an in vitro screening assay of cassava for resistance to CAD could serve as a convenient preliminary screening technique to discriminate CAD-resistant from CAD-susceptible cassava cultivars. The in vitro screening method considerably reduces time and labour in comparison with the current screening techniques of cassava, which involve field planting, inoculation and evaluation.     

Integrated control of Colletotrichum gloeosporioides on mango fruit in Taiwan by the combination of Bacillus subtilis and fruit bagging

Anthracnose disease caused by Colletotrichum gloeosporioides in Jingkwang mango grown in Taiwan was significantly reduced by the integration of fruit bagging with either B. subtilis strain LB5 or fungicides. The combined treatments were most effective in reducing early infection during the 2004 season, leading to 56.4 and 58.3% reduction, respectively, while in 2003 reduction accounted for 51 and 52.3%, respectively. Post-harvest application of B. subtilis strain LB5 cell suspensions on fruits already treated by bagging, bagging+LB5 and baggingfungicides in the field reduced anthracnose incidence significantly at all tested concentrations. These results indicate that biocontrol efficacy of B. subtilis LB5 may be due to the prevention of early fruit infection, thereby reducing significantly anthracnose incidence in ripening fruits to much lower levels than those obtained by using a conventional single post-harvest treatment.     

The distinctive population structure of Colletotrichum species associated with olive anthracnose in the Algarve region of Portugal reflects a host–pathogen diversity hot spot

Anthracnose ( Colletotrichum spp.) is an important disease of olive fruits. Diversity and biogeographic relationships of the olive anthracnose pathogens in the Algarve (Portugal) were investigated, along with host association patterns and disease levels during 2004–2007, to test the hypothesis that this region is a host–pathogen diversity hot spot. Diverse Colletotrichum acutatum and Colletotrichum gloeosporioides populations were identified based on rRNA-internal transcribed spacer and partial β-tubulin 2 gene sequences of 95 isolates. Spatial and temporal variations in the occurrence of the eight genetic entities of the pathogens were linked to olive biogeography. Disease occurrence patterns suggest that C. acutatum populations are more stable pathogens, while C. gloeosporioides populations appear to be more influenced by favourable conditions. Three unique C. acutatum populations were identified, but none of the eight populations were dominant, with the most frequent type representing only 27%. Thus, the population structure of olive anthracnose pathogens in the Algarve is distinct from other parts of Portugal and other world locations, where only one or two genetic entities are dominant. This pattern and level of genetic diversity in a restricted area, where oleaster (wild olive tree), ancient landraces and modern cultivars of olive occur in close proximity, suggests the Algarve as a centre of diversity of the anthracnose pathogens and corroborates recent work suggesting western Mediterranean as an important centre of olive diversity and domestication.     

Management of postharvest disease of mango anthracnose incited by Colletotrichum gleosporioides

Abstract

Among the seven fungal (Gliocladium virens, Trichoderma hamatum, T. harzianum, T. koningii, T. longibrachiatum, T. pseudokoningii and T. viride) and two bacterial (Bacillus subtilis and Pseudomonas fluorescens) antagonists screened against C. gloeosporioides under in vitro conditions, T. harzianum exhibited maximum inhibition followed by Pseudomonas fluorescens at 5 days after incubation. These fungal and bacterial antagonists were selected for application to fruits infected with pathogens. Fruits inoculated with C. gloeosporioides were dipped in spore/cell suspensions of fungal/bacterial antagonists and kept for different durations. The fungal antagonists T. harzianum and P. fluorescens were effective in checking the spread of pathogens on fruits compared with the pathogen-inoculated control.     

胶孢炭疽菌婆婆纳专化型侵染波斯婆婆纳的影响因子的研究

通过盆栽试验,研究了真菌自身生物学特性、杂草生长状况和环境因素等对胶孢炭疽菌婆婆纳专化型菌株QZ－97a侵染波斯婆婆纳的影响。结果表明,子叶期和衰老斯波斯婆婆纳感病性最强;培养7－14d后的孢子侵染力最强;病害发生的最佳温度范围是15－25℃;在保湿2－3d的条件下,露期中间的光照时间越短,病害发生越严重;保湿也可通过添加玉米粉和黄粉等介质来解决;达到理想致病效果的该菌株孢子悬浮液浓度必须在10^7个.ml^-1以上,由此可见,菌株QZ－97a在波斯婆婆纳发生时期的环境条件下可有效控制该杂草。     

Effect of Cuticular Wax Layers of Green and Red Pepper Fruits on Infection by Colletotrichum gloeosporioides

Colletotrichum gloeosporioides isolate KG13 caused necrotic, sunken anthracnose symptoms on unwounded, wax-removed, and wounded green pepper fruits and on wounded red fruits 7 days after inoculation. Hypersensitive reactions with small brownish discolorations, on some occasions, were found on unwounded red fruits. The isolate produced whitish symptoms with brown margins, but not the typical anthracnose on red fruits wax-removed by chloroform treatment. Generally, wax-removed red fruits, but not green ones, produced larger lesions and more conidia than untreated controls. Wounded pepper fruits had larger lesions than those with other treatments. More germinated conidia, appressoria, and infection hyphae were found on wax-removed fruits than on controls; however, differences between green and red fruits were not found. Cuticular wax layers of fruits were dissolved partially by chloroform and the outer epidermal cells were disrupted slightly. Anthracnose development was negatively related with fruit developmental stage. Well-developed fruits had more cuticular wax than less developed fruits. These results suggest that the cuticular wax layers of pepper fruits may play a significant role in fruit infection by C. gloeosporioides isolate KG13, and mainly determine the incompatibility of red fruits to the isolate. Biochemical differences may also play a role.     

Coexpression of a defensin gene and a thionin-like gene via different signal transduction pathways in pepper and Colletotrichum gloeosporioides interactions

The anthracnose fungus, Colletotrichum gloeosporioides, interacts incompatibly with the ripe fruit of pepper (Capsicum annuum). It interacts compatibly with the unripe-mature fruit. We isolated a defensin gene, j1-1, and a thionin-like gene, PepThi, expressed in the incompatible interaction by using an mRNA differential display method. Both genes were developmentally regulated during fruit ripening, organ-specifically regulated, and differentially induced during the compatible and incompatible interactions. Expression of the PepThi gene was rapidly induced in the incompatible-ripe fruit upon fungal infection. The fungus-inducible PepThi gene is highly inducible only in the unripe fruit by salicylic acid. In both ripe and unripe fruit, it was induced by wounding, but not by jasmonic acid. Expression of the j1-1 gene is enhanced by jasmonic acid in the unripe fruit but suppressed in the ripe fruit. These results suggest that both small and cysteine-rich protein genes are induced via different signal transduction pathways during fruit ripening to protect the reproductive organs against biotic and abiotic stresses.     

Irradiation induced physiological and morphological variation in Colletotrichum capsici,incitant of anthracnose of chillies

With the aid of radioactive phosphorus and gamma rays, a number of morphological and biochemical mutants ofColletotrichum capsici have been induced and these showed wide range of variability. Biochemical mutants mostly induced by means of p³² irradiation showed deficiency of amino acids or vitamins. Specific deficiency analysis of some of the biochemical mutants revealed requirements for lysine, methionine, glycine or serine and biotin. These biochemical mutants could not be distinguisbed from the wild type in morphological characters when grown on complete or otherwise suitable supplemented media.     

PCR-based detection and characterization of the fungal pathogens Colletotrichum gloeosporioides and Colletotrichum capsici causing anthracnose in papaya (Carica papaya l.) in the Yucatan peninsula

Colletotrichum gloeosporioides is the common causal agent of anthracnose in papaya (Carica papaya L.) fruits, and infection by this fungal pathogen results in severe post-harvest losses. In the Yucatán peninsula (Mexico) a different Colletotrichum species was isolated from papaya fruits with atypical anthracnose lesions. The DNAs from a variety of Colletotrichum isolates producing typical and atypical lesions, respectively, were amplified by PCR with C.gloeosporioides-specific primers. All isolates from typical anthracnose lesions yielded a 450 bp PCR product, but DNAs from isolates with atypical lesions failed to produce an amplification product. For further characterization, the rDNA 5.8S-ITS region was amplified by PCR and processed for sequencing and RFLP analysis, respectively, to verify the identity of the papaya anthracnose pathogens. The results revealed unequivocally the existence of two Colletotrichum species causing anthracnose lesions on papaya fruits: C. gloeosporioides and C. capsici. PCR-RFLP using the restriction endonuclease MspI reliably reproduced restriction patterns specific for C. capsici or C. gloeosporioides. The generation of RFLP patterns by MspI (or AluI or RsaI) is a rapid, accurate, and unequivocal method for the detection and differentiation of these two Colletotrichum species.     

Surface Ultrastructural Studies on Penetration and Infection Process of Colletotrichum gloeosporioides on Mulberry Leaf Causing Black Spot Disease

Unicelled conidia of Colletotrichum gloeosporioides germinated 3 h after inoculation producing single germ tubes. The orientation of the germ tubes and their lateral branches as they grew was towards the open stomata and away from closed stomata. By 24 h post-inoculation, the lateral branches had developed specialized infection vesicles either over the stomata or within the stomatal cavities. The infection vesicles produced primary infection hyphae which entered the leaves through stomatal openings. The disease symptoms became apparent by 6 days post-inoculation when clusters of abundant conidiophores emerged by rupturing the leaf epidermal layer, forming acervuli mostly near the base of idioblasts. The pressure exerted by the emerging conidiophores caused stretching of epidermal layer leading to the widening of the acervuli. The conidia are borne on the tips of the erect conidiophores.     

Sensitivity of mango anthracnose pathogen, Colletotrichum gloeosporioides, to the fungicide prochloraz in Taiwan

In order to monitor the sensitivity of the mango anthracnose fungus, Colletotricthum gloeosporioides, to the eradicative imidazole fungicide prochloraz, a total of 43 mango orchards were surveyed throughout the Tainan area, covering a 4000 ha region of mango plantations. These orchards were recognized as having undergone higher prochloraz application. A subpopulation, 55 isolates in total, collected from Wufeng, Taichung, served as a baseline population since no fungicide was ever used in this mango plantation. A total of 545 isolates were surveyed, and it was found that the IC50s (50% inhibitory concentration) fell within a range of 0.009-0.1554 microg/ml. No significant resistance was found in the field even with higher frequency of prochloraz application. One orchard (Yujing (Wu)) located in the Yujing area known had a higher frequency of prochloraz application, the IC50s were between 0.0204 - 0.1554 microg/ml. The average IC50 was 0. 0766 microg/ml, which was about five times higher than the baseline population (0.015 microg/ml). A significant t test indicated that these two sub-populations were different at p = 0.01. The results indicated that the dose-response of C. gloeosporioides to prochloraz shifted slightly toward higher IC50 over time. A further survey using 10 microg/ml as the threshold dosage was conducted, and the results of 1375 isolates collected throughout this region showed that no isolate could survive at this dosage. Knowing that the registered dosage for field use is 83.3 microg/ml, based on above results, the author concluded that there was no sign of prochloraz resistance in mango plantations 13 years after prochloraz registration in Taiwan.     

In vitro,greenhouse and field assessments of cassava lines for resistance to anthracnose disease caused by Colletotrichum gloeosporioides f.sp. manihotis

Fifty-three cassava lines were selected from breeding populations at the International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria and screened in vitro for resistance to cassava anthracnose disease (CAD). The in vitro inoculation of stem cuttings with the fungus Colletotrichum gloeosporioides f.sp. manihotis showed significant differences (p ± 0.05) in acervuli production and in the sensitivity of the cassava lines to the fungal infection after 7 days of incubation at 25 °C. Cassava lines 88/01084, 91/00595, 91/00475, 91/00344, 91/00684, 91/00313, 91/00422, and 91/00344 were highly resistant, with necrotic lesion sizes less than 7 mm. In contrast pedigree lines 88/02549, 89/0008, 91/00390 and 91/00402 were highly susceptible with the largest necrotic lesion size being greater than 20 mm. Ten cassava lines from the in vitro screening that showed varying levels of resistance to CAD were selected, based on their flowering abilities for diallel hydridization trials, and were further screened in greenhouse and field trials for CAD resistance. The greenhouse and field screening showed significant varietal differences (p ± 0.05) in sensitivity to the fungus. In all cases, the progeny lines showed correlated levels of resistance irrespective of the type of screening or assessments. Correlation analysis of the in vitro, greenhouse and field assessments showed that there was a good correspondence among all three methods of evaluating for CAD. This revised version was published online in June 2006 with corrections to the Cover Date.