作 者：
龚国淑;余霞;叶华智*;唐志燕;张敏;刘萍;陈希芹
关键词：
新月弯孢菌;玉米弯孢菌叶斑病;营养体亲和性;硝酸盐缺陷型(nit)突变体;菌落配对;菌丝融合
摘 要：
采用菌株直接配对、显微镜观察菌丝融合和硝酸盐缺陷型 ( nit)突变体互补测试法 ,对 44个来自不同地区的玉米弯孢菌叶斑病叶中的新月弯孢菌 ( Curvularia lunata)菌株进行了营养体亲和性分析。在野生型菌株的两两配对中 ,C.lunata菌株接触产生 4种反应类型 ,但无明显的抗衡反应产生。在菌丝融合显微观察中 ,光学显微镜下只见大多数菌丝反应为一菌丝向另一菌丝无限靠近 ,未见融合 ,但在电子显微镜下 ,发现两菌丝细胞已不再是独立的。这些结果表明 ,因两菌落间的抗衡反应和菌丝融合特征都不明显 ,故不宜采用直接配对和显微观察来划分 C. lunata的营养体亲和群。在 nit突变体互补测试中 ,菌株在 KCl O3 浓度 1 .5 %～ 3.0 %的 KPS中诱导表明 ,2 .0 %～ 3.0 % KCl O3 适宜于大多数菌株。抗氯酸盐突变体在 Czapek培养基中能鉴定出 nit突变体 ,但在 MM上却不能。全部 364 0抗氯酸盐突变体在 Czapek中共鉴定出 2 40个稳定的 nit突变体 ,其中 nit1占 5 9.2 % ,nit3占 39.2 % ,Nit M占 0 .8% ,nit D( 3种氮源都不能利用 )占 0 .8%。44个菌株中 ,2 4个 ( 5 5 % )获得了 nit突变体 ,2 0个 ( 45 % )还没有 ,仅 2个菌株 ( 1 2 4和 1 5 5 )各获得了 1个 Nit M突变体。各菌株突变体类型间只有 Nit M与 nit1或 nit3是异?
译 名：
Study on vegetative compatibility of Curvularia lunata isolated from corn in China
作 者：
GONG Guo shu, YU Xia, YE Hua zhi , TANG Zhi yan, ZHANG Min, LIU Ping, CHEN Xi qin (Agricultural College, Sichuan Agricultural University, Ya'an 625014, China)
关键词：
Curvularia lunata ; Corn Curvularia leaf spot disease; vegetative compatibility; nitrate non utilizing ( nit ) mutants; isolate pairing; hyphal anastomosis
摘 要：
Forty four isolates of Corn Curvularia leaf spot fungus ( Curvularia lunata ) were isolated from infected corn leaves collected from different regions in China. Vegetative compatibility of these isolates was assessed using different methods. By pairing isolates on potato dextrose agar (PDA) and observing contact reaction between expanding colonies, four reaction types were observed, but no clear barrage formations were found. Hyphal anastomosis patterns were examined by microscopy and electron microscopy. Of all pairing combinations, very few complete hyphal anastomosis was observed, but the anastomosis like types that one hyphae was infinitely close to another were commonly found under microscopy. However, under electron microscopy, a combination interaction could be observed where the two hyphal contacted. The results showed that no clear barrage formation and anastomosis signs occurred by isolate pairing. Nitrate non utilizing( nit ) mutants of C. lunata were used to study vegetativecompatibility of C. lunata . The isolates were cultured on potato sucrose agar(PSA) containing KClO 3(1.5%-3.0%) to generate chlorate resistant mutants(sectors). The result indicated that 2.0%- 3.0% chlorate in KPS was effective for most isolates. Nit mutants could be selected from chlorate reistant sectors on Czapek but not on minimal medium(MM). A total of 240 stable nit mutants were selec ted from 3640 sectors on Czapek, in which 59.2% were classed as nit 1, 39.2% as nit 3, 0.8% as NitM and 0.8% as nit D (unable to utilize nitrate, nitrite and hypoxanthine). Among the 44 tested isolates, 24(55%)generated nit mutants, and only two isolates(isolate 124 and 155) generated NitM mutants. The genetically different mutants from each isolate were complementally paired in all possible combinations. The results indicated that NitM was complementary with both nit 1 and nit 3 derived from the same parental isolate, and the remaining mutant combinations were unable to complement. Both isolate 124 and 155 were self compatible. Employing the two NitM mutants as tester, 5 isolates were classed to VCG1 while other 5 to VCG2.The remains did not belong to any VCG because of the absence of their nit or NitM mutants. These results suggest that complementation tests between nitrate non utilizing mutants may be more suitable to assign vegetative compatibility groups of C. lunata.
