The fungus <i>Colletotrichum truncatum</i> (Schw.) Andrus and Moore causes lentil anthracnose, which is a major challenge to lentil production in Western Canada. The pathogen infects leaves and stems, resulting in defoliation, stem girdling, plant wilting, and possibly plant death. Two races, Ct0 and Ct1, have been identified in the pathogen population in Canada. However, the differences in the infection process between the two races have not been described in detail. Currently, several lentil cultivars, such as CDC Redberry, CDC Robin, CDC Rosetown, CDC Rouleau, and CDC Viceroy, have resistance against race Ct1, whereas there are no cultivars showing resistance to race Ct0. The objective of this study was to investigate differences in the infection process between race Ct0 and race Ct1 using the fully susceptible cultivar Eston and the race Ct1-resistant cultivar CDC Robin. Experiments on glass well slides showed that race Ct0 had no inherently different conidium germination rate compared to race Ct1, and that differences in conidium germination between the two races on lentil plants were the result of specific interactions between the two races and lentil resistance. Investigations of the infection process of the two races on detached and attached leaves of both lentil cultivars were conducted starting 12 h postinoculation (hpi) until 72 hpi, including conidium germination, appressorium formation, and leaf penetration. Results indicated that differences in virulence of the two races may be related to the ability of conidia to germinate and form appressoria, as well as the ability of primary infection hyphae to grow in response to cues from the lentil cultivars. Furthermore, resistance of lentil to isolates of race Ct1 appeared to involve an inhibition in and/or delay of the spread of primary infection hyphae inside the plant tissue. Results of infection studies of one isolate from each race on attached leaves did not completely agree with results of the same isolates on detached leaves. Based on this study, race Ct0 and race Ct1 do not appear to be classical physiological races, but may represent aggressive races or some intermediate forms.
| Identifer | oai:union.ndltd.org:USASK/oai:usask.ca:etd-05012009-131917 |
| Date | 05 May 2009 |
| Creators | Wang, Jinghe |
| Contributors | Rowland, Gordon, Peng, Gary, Coulman, Bruce E., Banniza, Sabine, Wei, Yangdou |
| Publisher | University of Saskatchewan |
| Source Sets | University of Saskatchewan Library |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-05012009-131917/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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