He Peixin, Wang Ke, Cai Yingli, Liu Wei
School of Food and Biological Engineering, Zhengzhou University of Light Industry, Zhengzhou 450002, China.
Institute of Applied Mycology, Huazhong Agricultural University, Wuhan 430070, China.
Micron. 2017 Oct;101:108-113. doi: 10.1016/j.micron.2017.06.012. Epub 2017 Jun 29.
The commercial production of Morchella mushrooms, especially M. importuna, has been realized since 2012 in China, which facilitates the fundamental studies of Morchella spp. In this paper, the cytological characteristics at three stages of ascocarpic development and the nuclear behavior during meiosis and ascosporogenesis in cultivated strain M. importuna 1 was visualized by confocal laser scanning microscopy. The results suggested that the strain sporulated at sporulation stage of ascocarpic development. A total of six nuclear divisions typically took place during ascosporogenesis. The first and second divisions were meiotic in which the single diploid nucleus divided into four haploid nuclei. The subsequent mitosis gave rise to eight nuclei, and eight incipient ascospores with one nucleus in each spore were formed after spore delimitation in the clavate ascus. Then, the nucleus in most of the young ascospore underwent three successive mitoses producing 6-8 haploid nuclei in each mature spore, and thus the multinucleate ascospores in each ascus were all homokaryons. To the best of our knowledge, this is the first dynamic tracing study of nuclear behavior during meiosis and ascosporogenesis in cultivated morels, and the spore delimitation time is also the first report. The study will be beneficial for the genetics study and strain breeding of Morchella mushrooms.
自2012年以来，中国已实现了羊肚菌的商业化生产，特别是黑脉羊肚菌，这促进了羊肚菌属的基础研究。本文利用共聚焦激光扫描显微镜观察了栽培菌株黑脉羊肚菌1子囊果发育三个阶段的细胞学特征以及减数分裂和子囊孢子发生过程中的核行为。结果表明，该菌株在子囊果发育的产孢阶段形成孢子。在子囊孢子发生过程中通常共发生六次核分裂。第一次和第二次分裂是减数分裂，其中单个二倍体核分裂为四个单倍体核。随后的有丝分裂产生八个核，在棒状子囊中进行孢子界定后形成八个初始子囊孢子，每个孢子中有一个核。然后，大多数年轻子囊孢子中的核经历三次连续有丝分裂，每个成熟孢子中产生6-8个单倍体核，因此每个子囊中的多核子囊孢子均为同核体。据我们所知，这是首次对栽培羊肚菌减数分裂和子囊孢子发生过程中的核行为进行动态追踪研究，孢子界定时间也是首次报道。该研究将有助于羊肚菌的遗传学研究和菌株选育。
