Fifty-one isolates of Discula destructiva obtained from various Cornus species were evaluated using arbitrary signatures from amplification profiles (ASAP). ASAP analysis is based on dual-step arbitrary primer-based amplification procedure that produces “fingerprints of fingerprints” and in many instances increases detection of polymorphic DNA. This novel technique was able to distinguish groups of isolates from the northeast, middle and southeast range of the disease as well as western United States and Canada. The data supports the contention of recent and independent introduction of the disease on both east and west coasts, a genetic “bottleneck” that has limited diversity of the pathogen, and directionality of introduction of disease from coastal ports-of-entry to interior populations of C. florida and C. nuttalli.
G. Caetano-Anollés, R.N. Trigiano, and M.T. Windham
Nicole A. Cardwell and Gary L. McDaniel
The pathogenesis-related protein, chitinase, is implicated in the resistance mechanisms involved in dogwood anthracnose, which is caused by Discula destructiva. Chitinase isozymes were isolated from Discula-inoculated Cornus mas, a highly resistant species, and from inoculated C. florida, a highly susceptible species. Chitinase activity was identified in C. mas on days 2-12 following inoculation, but was expressed only on day 8 following inoculation in C. florida. Both dogwood species expressed a constitutive chitinase level in noninoculated control leaves, but Discula-inoculated leaves of C. mas contained three chitinase isozymes, whereas C. florida leaves expressed only two. Molecular masses of isozymes were 21, 32, and 35 kDa for C. mas and 21 and 35 kDa for C. florida. Isoelectric focusing demonstrated three chitinase isozyme isoelectric points for C. mas (pI = 5.6, 6.8, and 8.9), but only two for C. florida (pI = 5.6 and 6.8). These differences in synthesized isozymes and rate of accumulation suggest that chitinase may have a role in the defense of dogwood against D. destructiva infection.
M.T. Windham, E.T. Graham, W.T. Witte, J.L. Knighten, and R.N. Trigiano
R. N. Trigiano, G. Caetano-Anollés, B. J. Bassam, and M. T. Windham
DNA Amplification Fingerprinting (DAF) was used to characterize ten isolates of Discula destructiva Redlin and three isolates of an undescribed species of Discula, the causal organisms of dogwood (Cornus species) anthracnose. Isolates were obtained throughout the disease range in the eastern United States and DAF profiles generated with ten arbitrary oligonucleotide primers. Very few polymorphic loci (27/298) were detected between isolates of D. destructiva; whereas, a greater number were observed between and among the isolates of Discula species. Relationships among and between the two fungal groups were analyzed using PAUP and UPGMA and indicate that the genome of D. destructiva is highly conserved throughout the distribution. In contrast, isolates of Discula species exhibited greater variability. This suggests that D. destructive was recently introduced to the eastern United States.
Diane Feliciano Cayanan, Mike Dixon, Youbin Zheng, and Jennifer Llewellyn
leaves of Weigela also exhibited curling. Fifteen percent of the leaves of Physocarpus displayed chlorosis as a light yellow color. All Cornus exposed to nonchlorinated water during this experiment displayed anthracnose ( Discula destructiva ), a
Robert N. Trigiano, Alan S. Windham, Mark T. Windham, and Phillip A. Wadl
United States ( Daughtrey et al., 1996 ) were ravaged by an epidemic of dogwood anthracnose caused by Discula destructiva ( Redlin, 1991 ), an introduced pathogen ( Trigiano et al., 1995 ). This disease can cause the death of seedlings in as little as
Phillip A. Wadl, John A. Skinner, John R. Dunlap, Sandra M. Reed, Timothy A. Rinehart, Vincent R. Pantalone, and Robert N. Trigiano
Discula destructiva sp. nov., cause of dogwood anthracnose Mycologia 83 633 642 Reed, S.M. 1999 Development of a labor-efficient hand pollination procedure for flowering dogwood J. Environ. Hort. 17 92 94 Reed, S.M. 2004 Self-incompatibility in Cornus
Phillip A. Wadl, Mark T. Windham, Richard Evans, and Robert N. Trigiano
urban and suburban landscapes. Across this range, flowering dogwoods have been severely affected by dogwood anthracnose [ Discula destructiva ( Redlin, 1991 )] and powdery mildew [ Erysiphe pulchra ( Li et al., 2009 )]. Because of the importance of
Virginia I. Lohr
problems that have spread through landscape plantings with low biodiversity. These pests, which attack more than one species within a commonly planted genus, include dogwood anthracnose ( Discula destructiva ), hemlock woolly adelgid ( Adelges tsugae ), and
Phillip A. Wadl, Xinwang Wang, Andrew N. Trigiano, John A. Skinner, Mark T. Windham, Robert N. Trigiano, Timothy A. Rinehart, Sandra M. Reed, and Vincent R. Pantalone
( Dirr, 1998 ). Additionally, kousa dogwoods are regarded as more resistant to dogwood anthracnose ( Discula destructiva ) and powdery mildew ( Erysiphe pulchra ) than flowering dogwood ( Hagan et al., 2001 ; Ranney et al., 1995 ). Kousa dogwood is