摘要:
本研究以贵阳秋季栽培的2个米苦荞(F.tataricum,贵米苦荞18-1号和贵黑米苦荞12号)、2个多苦荞(F.tatari-cymosum,贵多苦荞003C和贵多苦荞60)、2个甜荞(F.esculentum,贵红花甜荞2号和1412-1)、2个常规苦荞(F.tataricum,定苦荞1号和六苦2017)为材料。对其成熟期种子果壳和籽粒进行了黄曲霉分离鉴定,并采用高效液相色谱法对所有品种果壳和籽粒中分离出的黄曲霉菌株进行AFB1、AFB2、AFG1和AFG2毒素的检测。结果表明,所有品种果壳中均没有分离出黄曲霉菌落;4类荞麦籽粒中仅米苦荞分离出了黄曲霉菌落,共分离出4株黄曲霉菌株。其中贵米苦荞18-1号黄曲霉带菌率为1.56%,贵黑米苦荞12号黄曲霉带菌率为0.78%。分离菌株形态学和ITS序列扩增产物测序结果与已知黄曲霉菌序列完全一致。毒素检测结果表明不同品种之间产毒素差异显著,所有品种籽粒中只有米苦荞中检出4种毒素,贵米苦荞18-1号产AFB1最高为(5.861±0.055) μg/kg、AFB2最少为(1.605±0.052) μg/kg,贵黑米苦荞12号产AFB1最高为(14.475±0.533) μg/kg、AFG2最少为(3.393±0.151) μg/kg;籽粒产毒量远大于分离菌株产毒量;各分离出菌株之间产毒素能力差异显著,最大产AFT为(11.102±0.095) μg/kg、最小产AFT为(1.794±0.024) μg/kg。上述结果显示供试米苦荞籽粒带菌来源可能是由于果壳开裂籽粒外露后部分籽粒被直接侵染所致。所得结果可为米苦荞中黄曲霉抗性育种研究及荞麦种子的保存、运输、储藏等研究奠定基础。
Abstract:
In this study, two related rice tartary buckwheat lines (F.tataricum, Guimiku 18-1 and Guiheimi 12), two perennial tartary buckwheat lines (F.tatari-cymosum, Guiduoku 003C and Guiduoku 60), two common buckwheat lines (F.esculentum, Guihongtian 2 and 1412-1), two thick-shell conventional tartary buckwheat lines (F.tataricum, Dingku 1 and Liuku 2017) were cultivated in Guiyang in autumn of 2018. The A.flavus was isolated and identified from shell and rice grain at maturation stage, and high performance liquid chromatography (HPLC) was used to detect the aflatoxin of AFB1, AFB2, AFG1, AFG2 in all A. flavus strains isolates from shells and grains. The results showed that there were no A.flavus colonies from the shell of all varieties and the rice grains of common buckwheat, convention tartary buckwheat, and perennial tartary buckwheat. A. flavus colonies were isolated only from rice grains of rice tartary buckwheat, and there were a total of 4 strains of A. flavus isolated. There were the incidence of A. flavus of 1.56% and 0.78% in mature seeds of Guimiku 18-1 and Guiheimi 12 respectively. The isolated strains morphology and sequencing results of ITS sequence amplification products were identical with those of A. flavus. The results of toxin test showed that there were significant differences in toxin contents among different varieties and in toxin production ability among different strains. Only rice tartary buckwheat were detected four toxins in all varieties, the maximum production of Guimiku 18-1 was AFB1, (5.861±0.055) μg/kg, AFB2 was the minimum (1.605±0.052) μg/kg, the maximum production of Guiheimi 12 was AFB1 (14.475±0.533) μg/kg, AFB2 was the minimum (3.393±0.151) μg/kg;The toxin content of rice grains was much higher than that of isolated strains;there were significant differences in toxin-producing capacity among isolated strains, The maximum production of AFT was (11.102±0.095) μg/kg and the minimum production of AFT was (1.794±0.024) μg/kg. These results suggested that the A. flavus source in rice tartary buckwheat rice grains may be from the direct infection of some rice grain exposure resulting from shell partly dehiscence. The above results could lay a foundation for the study of resistance breeding of A. flavus in buckwheat and the preservation, transportation and storage of buckwheat seeds.
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