紫外线诱导小麦条锈菌毒性突变及突变体的RAPD分析

以夏孢子相对致死率90%左右作为紫外线处理最适时间,发现8min为小麦条锈菌条中29号单孢菌系(CY29-3)最适处理时间,其夏孢子相对致死率达88.97%。CY29-3的夏孢子经紫外线处理、扩繁、筛选品种筛选及4代的稳定选择后,获得了两个毒性变异的突变菌株。毒性突变产生的Jubi菌株对尤皮Ⅱ号的毒性增强,反应型由野生菌系的0型变为4型;非毒性突变产生的Funo菌株在阿夫上的反应型由野生菌系的4型变为2型。研究结果表明两突变菌株在鉴别寄主上的反应型和毒性范围也明显不同于野生菌系,说明紫外线诱导的小麦条锈菌变异是不定向和复杂的。对野生菌系和两个突变菌株进行RAPD分析后发现,两突变菌株与野生菌系之间的DNA多态性存在显著差异,多态率分别为10.58%和11.57%,说明紫外线可使小麦条锈菌基因组DNA发生较大的变化且突变位点比较复杂。

MUTATION OF PATHOGENICITY INDUCED BY ULTRVIOLET RADIATION IN PUCCINIA STRIIFORMIS F. SP. TRITICI AND RAPD ANALYSIS OF MUTANTS

The reasonable time of ultraviolet radiation treatment to urediospores of Chinese wheat yellow rust race 29 (CY29-3) is the time of 90% relative percentage of lethality of urediospores. The 88.97% relative percentage of lethality of urediospore was gotten after 8 minutes ultraviolet radiation treatment. After treating urediospores of CY29-3 by ultraviolet radiation for 8 minutes, propagating the treated urediospores on susceptible wheat cultivar, as well as screening on wheat cultivars, two mutants in pathogenicity, Jubi isolate and Funo isolate, were obtained through stability test for 4 generations. Reaction type of Jubi isolate on Jubilejina 2 host was 4, different from the original race with reaction type 0. Funo isolate showed reaction type 2 on Funo host, while the original race is 4. The results demonstrated that the pathogenicity of two mutant cultures were significantly different from the original race CY29-3. The virulence of two mutants on differential hosts and some novel cultivars were significantly different from the original race CY29-3 and all known races of yellow rust by greenhouse seedling tests, too. The results suggested that the pathogenicity variations of Puccinia striiformis f.sp. tritici after UV radiation treatment were non-directional and complicated. RAPD analysis was conducted to compare the genomic DNA of mutant cultures to original race. The polymorphic rates of Jubi isolate and Funo isolate are 10.58% and 11.57%, respectively. The results showed UV radiation could cause obvious variation of genome DNA of P. striiformis f.sp. tritici.