Cellular and proteomic events associated with the localized formation of smut-gall during Zizania latifolia–Ustilago esculenta interaction

Mixed Transcriptome Analysis Revealed the Possible Interaction Mechanisms between Zizania latifolia and Ustilago esculenta Inducing Jiaobai Stem-Gall Formation

“…is a perennial aquatic plant that is an ancient cereal crop and has been cultivated for more than 2000 years in China [1]. However, after being parasitized by Ustilago esculenta, Z. latifolia no longer undergoes inflorescence and forms seeds but stimulates the upper parts of the stem expansion and becomes a vegetable, which is a common occurrence in China, India, and Japan in Southeast Asia [2,3]. In nature, U. esculenta is a number of smut fungi belonging to the basidiomycetes.…”

“…Smut fungi, such as U. maydis, Sporisorium reilianum, U. hordei, Urocystis tritici, and Thecaphora solani, consistently cause devastating effects on the host plant, preventing crop growth and causing huge economic losses; smut disease is sometimes the reason for famine in any particular area or place [4,5]. While during the long process of artificial selection and coevolution, U. esculenta and Z. latifolia reached a clever balance between plant's disease resistance and fungal infection [3,6], the infected stem was no longer a common disease tumor (full of black powder) but formed an edible, white swollen culm gall, which was found to be delicious and nutritious, was deeply loved by the people and was called "Jiaobai" in China [6,7]. Jiaobai cultivation has become a pillar industry in some areas of the Zhejiang and Jiangsu provinces and other regions in China, and has high economic value [1,8].…”

“…U. esculenta, as a living trophic fungus, specifically infects Z. latifolia plants, Even in winter, smut fungi still exist in the old roots and stolon buds of the host plant. U. esculenta usually infects the buds of underground stems through vascular tissues, parenchyma or vascular bundles, after which linear, branching, aggregate, and polymerized hyphae and other changes along the intercellular space or through the cells of the host plant are observed during the transition from the seedling stage to fleshy, stem-swelling stage [3,8]. This process is also accompanied by a series of physiological changes, such as an increase in plant hormones, carbohydrate accumulation, and an enhancement of leaf photosynthesis during the expansion of stem galls.…”

“…This process is also accompanied by a series of physiological changes, such as an increase in plant hormones, carbohydrate accumulation, and an enhancement of leaf photosynthesis during the expansion of stem galls. A large number of differentially expressed genes (DEGs) involved in material metabolism, signal transduction, plant-fungal interactions and other pathways have been found in transcriptome and proteome analyses during the different developmental stages of Z. latifolia [3,9,10].…”

Deeper Understanding of the Mechanism Promoting Gall Formation of Zizania latifolia under Fenaminosulf Treatment

“…The basidiomycetes fungus Ustilago esculenta could speci cally colonize Z. latifolia hosts by invading their meristems. There, the mycelium of U. esculenta grows in or between the cells in the meristem near the stem tip, which prevents the infected plant from owering and causes the formation of the localized, edible swelling structure [10][11][12][13][14] . The plant pathogen U. esculenta is unique among the smut fungi that are plant pathogens, which mainly parasitize grasses and cause 'smut disease' [15][16][17][18] , because it does not induce chlorosis symptoms in the host, or necrosis, but instead induces the formation of differentiated galls on the culm upon infection 12,[19][20][21][22][23] .…”