Department of Plant Pathology, University of Brasília, Brasília, DF, 70.910-900, Brazil; Agricultural Microbiology Laboratory, Embrapa Rice and Beans, Santo Antônio de Goiás, 75375-000, GO, Brazil.
Agronomy School, Federal University of Goiás, Goiânia, GO, 74.690-900, Brazil.
Microbiol Res. 2020 Jan;231:126353. doi: 10.1016/j.micres.2019.126353. Epub 2019 Oct 15.
Cladosporium spp. is a cosmopolitan fungal genus. In the literature, it has been reported as a biological agent for controlling several plant diseases, but its mechanism of action has never been clarified. The present study aims to identify Cladosporium spp. based on the DNA phylogeny of nine isolates obtained from the phylloplane of rice and their potential antagonistic activity against the main fungal pathogens that affect rice crop. Nine isolates of Cladosporium spp. were identified based on DNA phylogeny, molecular and morphological characterization, and their antagonistic effects with the rice pathogens C. miyabeanus, M. oryzae, M. albescens and S. oryzae. Four isolates were selected to study lytic enzymes such as β-1,3-glucanase, chitinase and protease, and only one isolate was selected for a conidial germination and appressoria formation assay. The nine isolates were identified as C. cladosporioides, C. tenuissimum and C. subuliforme. Four isolates, identified as C. cladosporioides, inhibited the mycelial growth of rice pathogens such as C1H (68.59%) of S. oryzae, C5 G (74.32%) of C. miyabeanus, C11 G (75.97%) of M. oryzae and C24 G (77.39%) of M. albescens. C24 G showed a high activity of lytic enzymes, was tested against C. miyabeanus and M. oryzae, and inhibited conidial germination and appressorium formation by more than 59.36%. The characterization of C. cladosporioides suggested this species as a potential bioagent for the management of several rice diseases, especially rice blast. This is the first time that a potential biological agent from the genus Cladosporium identified at the species level was isolated from the rice phylloplane, and some of its mechanisms of action were demonstrated, such as increasing lytic enzyme activity against rice pathogens.
茎点霉属是一种世界性的真菌属。在文献中，它已被报道为控制几种植物病害的生物制剂，但作用机制从未得到澄清。本研究旨在根据从水稻叶片上获得的 9 个分离物的 DNA 系统发育鉴定茎点霉属，并研究其对影响水稻作物的主要真菌病原体的潜在拮抗活性。根据 DNA 系统发育、分子和形态特征，从水稻叶片上分离到的 9 个茎点霉属分离物被鉴定为 C. cladosporioides、C. tenuissimum 和 C. subuliforme。选择 4 个分离物研究 β-1,3-葡聚糖酶、几丁质酶和蛋白酶等裂解酶，仅选择 1 个分离物进行分生孢子萌发和附着胞形成测定。从水稻叶片上分离到的 9 个茎点霉属分离物被鉴定为 C. cladosporioides、C. tenuissimum 和 C. subuliforme。4 个分离物，鉴定为 C. cladosporioides，抑制了水稻病原菌的菌丝生长，如 S. oryzae 的 C1H（68.59%）、C. miyabeanus 的 C5G（74.32%）、M. oryzae 的 C11G（75.97%）和 M. albescens 的 C24G（77.39%）。C24G 表现出较高的裂解酶活性，对 C. miyabeanus 和 M. oryzae 进行了测试，抑制了分生孢子的萌发和附着胞的形成，超过 59.36%。C. cladosporioides 的特征表明该物种可能是几种水稻病害，特别是稻瘟病的生物防治剂。这是首次从水稻叶片上分离到茎点霉属的潜在生物制剂，并在种水平上进行了鉴定，并且证明了一些作用机制，例如增加对水稻病原菌的裂解酶活性。
