title: Effects of Temperature on Systemic Infection and Symptom Expression of Turnip mosaic virus in Chinese cabbage (Brassica campestris).
abstract: Using the Chinese cabbage (Brassica campestris) cultivar 'Chun-goang' as a host and turnip mosaic virus (TuMV) as a pathogen, we studied the effects of ambient temperature (13°C, 18°C, 23°C, 28°C and 33°C) on disease intensity and the speed of systemic infection. The optimal temperature for symptom expression of TuMV was 18-28°C. However, symptoms of viral infection were initiated at 23-28°C and 6 days post infection (dpi). Plants maintained at 33°C were systemically infected as early as 6 dpi and remained symptomless until 12 or 22 dpi, depending on growth stage at the time of inoculation. It took 45 days for infection of plants grown at 13°C. Quantitative real-time polymerase chain reaction (q-PCR) results showed that the accumulation of virus coat protein was greater in plants grown at 23-28°C. The speed of systemic infection increased linearly with rising ambient temperature, up to 23°C. The zero-infection temperature was 10.1°C. To study the effects of abruptly elevated temperatures on systemic infection, plants inoculated with TuMV were maintained at 10°C for 20 d; transferred to a growth chamber at temperatures of 13°C, 18°C, 23°C, 28°C, or 33°C for 1, 2, or 3 d; and then moved back to 10°C. The numbers of plants infected increased as duration of exposure to higher temperatures and dpi increased.
authors.affiliation: National Institute of Horticultural & Herbal Science, RDA, Jeju 690-150, Korea.
authors.forename: Bong Nam
authors.initials: BN
authors.lastname: Chung
authors.affiliation: National Institute of Horticultural & Herbal Science, RDA, Jeju 690-150, Korea.
authors.forename: Kyung San
authors.initials: KS
authors.lastname: Choi
authors.affiliation: National Institute of Horticultural & Herbal Science, RDA, Jeju 690-150, Korea.
authors.forename: Jeong Joon
authors.initials: JJ
authors.lastname: Ahn
authors.affiliation: National Institute of Horticultural & Herbal Science, RDA, Jeju 690-150, Korea.
authors.forename: Jae Ho
authors.initials: JH
authors.lastname: Joa
authors.affiliation: National Institute of Horticultural & Herbal Science, RDA, Jeju 690-150, Korea.
authors.forename: Ki Seck
authors.initials: KS
authors.lastname: Do
authors.affiliation: National Institute of Horticultural & Herbal Science, RDA, Jeju 690-150, Korea.
authors.forename: Kyo-Sun
authors.initials: KS
authors.lastname: Park
keywords: TuMV; chinese cabbage; disease symptoms; temperature