The Preservation of Cauliflower Witches'-Broom Phytoplasma by Tissue Culture

Cauliflower (Brassica oleracea var.botrytis) witches'-broom phytoplasma diseased plants collected from Yuanmou County, Yunnan Province, were the source for tissue culture experiments. The tissue cultured seedlings were preserved in refrigerator at 4 ℃ to 8 ℃ and in light incubator at normal temperature, respectively. After a period of observation and subculture, the result showed that the stems of infected plants as explant material and the bud lure medium could be better used for cauliflower plantlets. Meanwhile, the low-temperature preservation could prolong the interval time of subculture (1 time per 2~3 months).In the preservation period, light supplement on seedlings for 3 to 7 days per month could be sustainable preserved and the cauliflower witches'-broom phytoplasma still appeared in the tissue culture seedling after 12 months confirmed by polymerase chain reaction detection. Thus, the purpose for long-term preservation of phytoplasma strain has been achieved.