Infection process of Gaeumannomyces graminis var. graminis on the roots and culm of rice

• Ano de defesa: 2016
• Autor(a) principal: Hawerroth, Caroline
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Arroz - Doenças e pragas; Fungos fitopatogênicos; Gaeumannomyces graminis; Oryza sativa; Microscopia eletrônica de varredura; Fitopatologia
• Link de acesso: https://locus.ufv.br//handle/123456789/27454

Crown sheath rot, caused by the ascomycete Gaeumannomyces graminis var. graminis, infects the roots and the base of the culm of rice and causes early grains maturation, the death of the tillers and reduced yield. Considering the little information for the interaction rice-G. graminis var. graminis at the microscopical level, this study aimed to gain novel insights regarding the infection process of this important soilborne pathogen on the roots and culm of rice plants by using both light and scanning electron microscopy. In the roots, the fungus initially colonized the epidermal, exodermal and sclerenchyma cells. At 15 days after inoculation (dai), prominent fungal hyphae colonized the cortex as well as clusters of perithecia were noticed into the roots. At 20 dai, the fungus reached the central cylinder. There was intense fungal colonization in the culm-base of the plants that resulted in the formation of a mycelial mat on both adaxial and abaxial surfaces of the leaf sheaths. At 25 dai, fungal growth was noticed in the parenchyma cells, the vascular bundles and the air spaces. Perithecia emerged through the base of prophyllum and the first leaf sheath at 30 dai. The results of this study provide new insight into the infection process of G. graminis var. graminis on rice plants and may contribute to the development of more effective control measures to reduce the crown sheath rot in the field.