淮稻5号的真菌多样性及其储藏过程中可培养的优势真菌

【目的】从传统形态学和分子生物学两方面对2013年的淮稻5号中分离的真菌进行鉴定，并研究淮稻5号在不同储藏条件下优势菌株的演变规律，为该品种稻谷储藏过程中的真菌种属研究及霉变防控提供参考。【方法】淮稻5号中的可培养真菌通过采用孟加拉红和马铃薯葡萄糖琼脂（PDA）两种培养基，按照国标GB 4789.15-2010的操作获得。将采自4个不同地区的淮稻5号混匀，分别调节其水分含量为14.5%和18.5%后放入25℃人工气候箱内模拟储藏，逐月取出模拟储藏的稻谷样品进行传统培养以确定可培养的优势真菌。真菌的种属分别通过菌落、菌丝及孢子的形态学观察，对照《中国真菌志》等参考文献确定；同时通过PCR分别扩增相应真菌的内转录间隔区（ITS）和28S rDNA的部分序列，连接T载体后测序，通过构建系统发育树进而确定真菌的种属。【结果】从4个地区的2013年淮稻5号稻谷中共分离得到33株真菌，主要为青霉（Penicillium）、曲霉（Aspergillus）和镰刀菌（Fusarium）等菌属，其中青霉属与曲霉属最多，分别为16株和15株，分别占分离所得菌株的48.5%和45.5%，表明青霉和曲霉是2013年淮稻5号稻谷中可培养真菌的优势菌属。而镰刀菌属的真菌仅2株，仅占分离所得菌株的6%。模拟储藏的结果表明，水分含量为14.5%的淮稻5号在25℃条件下储藏6个月时出现优势菌株，为橘灰青霉（Penicillium aurantiogriseum），并且该优势菌在模拟储藏的第7、8个月持续存在。水分含量为18.5%的淮稻5号在25℃条件下储藏7个月时出现优势菌株，为酵母菌，且该优势菌在模拟储藏8个月时依然存在。【结论】2013年淮稻5号中分离获得33株真菌，主要包括16株青霉、15株曲霉以及2株镰刀菌，表明青霉和曲霉是2013年淮稻5号稻谷中的优势菌属。不同水分含量的稻谷在储藏过程中可能出现不同的优势菌株。

Fungal Diversity of Huaidao No. 5 Rice and the Dominant Culturable Fungal Strains During Storage

【Objective】The objective of this study is to determine the fungal genus in 2013 Huaidao No. 5 rice by traditional morphological observation and molecular biology method, as well as to investigate the dominant fungal strains on Huaidao No.5 rice under different storage conditions. Results of this study could provide a scientific basis for the fungal genus identification and control of fungi growth in Huaidao No. 5 rice. 【Method】The culturable fungal strains were obtained by using both Rose Bengal and potato dextrose agar (PDA) media, following the instruction of GB 4789.15-2010. The Huaidao No. 5 rice collected from 4 different regions were mixed and then the moisture content were adjusted to 14.5% and 18.5% respectively. The samples were stored in the artificial climate equipment under 25℃. The culturable dominant fungi were determined by traditional culturing of the rice samples monthly removed from the simulated storage conditions. The fungal genus were identified by morphological observation of colonies, hyphae and spores by referencing to the . At the same time, the internal transcribed spacer (ITS) and 28S rDNA were amplified by PCR, and then ligated into T vector and sequenced. The fungal species were identified by constructing phylogenetic trees.【Result】In terms of fungal diversity in Huaidao No. 5 rice: 33 strains of fungi were isolated from four regions of the 2013 Huaidao No. 5 rice, mainly for Penicillium, Aspergillus and Fusarium, including 16 strains of Penicillium and 15 strains of Aspergillus, accounting for the separated strains of 48.5% and 45.5%, respectively, indicating that Penicillium and Aspergillus are the dominant fungi genus in 2013 Huaidao No. 5 rice. There are only 2 strains of Fusarium, which accounted for only 6% of the isolates. Simulation storage experiment results showed that Penicillium aurantiogriseum appeared to be the dominant strain from 6 month in moisture content of 14.5% for Huaidao No. 5 rice under 25℃ storage, and this strain persisted to be dominant in 7 and 8 months storage. While for the Huaidao No. 5 rice with a moisture content of 18.5%, a yeast strain appeared to be the dominant from 7 month and this strain persisted to be dominant at 8 month under 25℃ storage.【Conclusion】 33 strains of fungi were separated and identified from 2013 Huaidao No. 5 rice, including 16 strains of Penicillium and 15 strains of Aspergillus, respectively, indicating that Penicillium and Aspergillus are the dominant fungi genus in 2013 Huaidao No. 5 rice. And under different simulated storage conditions, different cultural fungal strains dominated the Huaidao No. 5 rice with different moisture content.