Key Laboratory of Crop Gene Resources and Germplasm Enhancement on Loess Plateau, Center for Agricultural Genetic Resources Research, Shanxi Agricultural University, Taiyuan, 030031, China.
Sci Rep. 2021 Jan 13;11(1):1243. doi: 10.1038/s41598-020-80273-6.
Spikelet rot disease (SRD) is an emerging disease of the grain surface of naked oat in China that affects both grain yield and quality. The typical symptom is discoloration from the black structures of the causal fungi. Here, we investigated the fungal communities on the grain surfaces of cultivar Bayou 13 grown in ten ecological oat-producing regions of China, to identify the main pathogens of naked oat SRD. Our results showed that the growth of Alternaria spp. and Davidiella spp. exhibited a competitive relationship and was mainly affected by the elevations of all 10 ecological regions. The dominant pathogens were Davidiella spp. in Shannan Prefecture in Tibet and Haidong Prefecture in Qinghai Province and Alternaria spp. in the other eight regions. The ratios of black pathogens of interest to all pathogens in Shannan Prefecture and Haidong Prefecture were significantly lower than those of the other eight regions, thus indicating that SRD mainly occurred in regions below 2000 m (elevation). We isolated black fungal pathogens from grain surfaces and deduced that they were Alternaria spp. by sequence comparison. The blackened appearance of the grain surfaces was more evident under spray inoculation with a spore suspension of Alternaria than under the control in greenhouse experiments. The recovered pathogen was the same as the pathogen used for inoculation. We thus concluded that Alternaria alone causes naked oat SRD and mainly infects naked oat in regions below 2000 m, which provides a basis for the recognition and management of SRD of naked oat.
小穗腐病（SRD）是中国裸燕麦粒表的一种新兴病害，会影响裸燕麦的产量和品质。该病的典型症状是由病原菌的黑色结构导致的变色。本研究调查了中国 10 个生态燕麦产区种植的品种 Bayou 13 的燕麦粒表真菌群落，以鉴定裸燕麦 SRD 的主要病原菌。结果表明，链格孢属和戴维氏菌属的生长呈竞争关系，主要受 10 个生态区海拔的影响。主要病原菌是西藏山南地区和青海海东地区的戴维氏菌属，以及其他 8 个地区的链格孢属。山南地区和海东地区关注的黑色病原菌与所有病原菌的比例明显低于其他 8 个地区，表明 SRD 主要发生在海拔 2000 m 以下的地区。我们从燕麦粒表分离出黑色病原菌，并通过序列比对推断它们是链格孢属。在温室试验中，用链格孢孢子悬浮液喷雾接种比对照更明显地使燕麦粒表面变黑。回收的病原菌与接种用的病原菌相同。因此，我们得出结论，链格孢单独引起裸燕麦 SRD，主要感染海拔 2000 m 以下的裸燕麦，为裸燕麦 SRD 的识别和管理提供了依据。
