College of Resources and Environment, Huazhong Agricultural University / Hubei Provincial Engineering Laboratory for New-Type Fertilizer / Research Center of Trace Elements / Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Wuhan 430070, China.
College of Resources and Environment, Huazhong Agricultural University / Hubei Provincial Engineering Laboratory for New-Type Fertilizer / Research Center of Trace Elements / Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs, Wuhan 430070, China.
Ecotoxicol Environ Saf. 2019 Nov 15;183:109503. doi: 10.1016/j.ecoenv.2019.109503. Epub 2019 Aug 5.
Sclerotinia sclerotiorum (S. sclerotiorum) is a devastating fungal pathogen with worldwide distribution, and threatened the agro-ecological safety in the long term. To control the damage caused by Sclerotinia diseases, as well as consider the fungicide resistance and chemical residues, strategy of which plant nutritional regulation, as an eco-friendly approach, is gaining much significance. Selenium (Se), as a beneficial microelement for plant, has been manifested to be effective in inhibiting the mycelial growth of S.sclerotiorum in our previous study. In the present study, we observed that Se (both selenate and selenite) inhibited the formation of sclerotia, which is an important life form in the disease cycle of S. sclerotiorum. And the inhibition ratios of number of sclerotia in treatments of Se(VI) and Se(IV) were 54.55% and 43.84%, respectively; the inhibition ratios of weight of sclerotia in treatments of Se(VI) and Se(IV) were 42.29% and 25.67%, respectively. Results suggested that Se inhibited mycelial growth, severely damaged sclerotial ultrastructure, reduced the capacity of acid production, decreased superoxide dismutase (SOD) and catalase (CAT) activities, increased the content of hydrogen peroxide (HO) and superoxide anion (O) in mycelium, and all of these resulted in the reduction in sclerotial formation. Further studies revealed that Se application in medium increased Se concentration in sclerotia and thus inhibited sclerotial germination. Moreover, the pathogenicity of mycelia germinating from sclerotia that pretreated with Se, decreased significantly to rape leaves. These findings broadened our understanding of Se application in plant protection, as well as provided evidences for developing environment-friendly fungicide for S. sclerotiorum control.
核盘菌（Sclerotinia sclerotiorum）是一种具有全球分布的破坏性真菌病原体，长期以来威胁着农业生态安全。为了控制由核盘菌病造成的损害，同时考虑到杀菌剂抗性和化学残留问题，植物营养调控策略作为一种环保方法，正变得越来越重要。硒（Se）作为植物的有益微量元素，在我们之前的研究中已被证明能有效抑制核盘菌菌丝的生长。在本研究中，我们观察到硒（包括硒酸盐和亚硒酸盐）抑制了核盘菌菌核的形成，菌核是核盘菌病害循环中的一种重要生命形态。Se(VI)和 Se(IV)处理对菌核数量的抑制率分别为 54.55%和 43.84%；Se(VI)和 Se(IV)处理对菌核重量的抑制率分别为 42.29%和 25.67%。结果表明，硒抑制了菌丝的生长，严重破坏了菌核的超微结构，降低了产酸能力，降低了超氧化物歧化酶（SOD）和过氧化氢酶（CAT）的活性，增加了菌丝中过氧化氢（HO）和超氧阴离子（O）的含量，导致菌核形成减少。进一步的研究表明，硒在培养基中的应用增加了菌核中的硒浓度，从而抑制了菌核的萌发。此外，用硒预处理后的菌核萌发的菌丝对油菜叶片的致病性显著降低。这些发现拓宽了我们对硒在植物保护中应用的理解，为开发防治核盘菌的环保型杀菌剂提供了依据。
