Fluorescence Labelling Of Bipolaris Sorokiniana And The Study Of Interaction Between Fungus And Wheat

Bipolaris sorokiniana (Sacc. in Sorok.) Shoem. that can infect wheat, barlay andoat and so on cereal crops is a soil-born fungus. Besides Bipolaris sorokiniana cancause common rot in root, it also can cause leaf spot which makes upperground partsof crops wither and so on. In recent years, Fluorescence protein getted a very widelyapplication in animal, plant and fungal. It can directly observe fungus infection andcolonization in plant tissues via fluorescence protein labeled strain Bipolarissorokiniana, and study the interaction between plant and pathogenic bacteria.Gene gfp was transferred into B. sorokiniana strain Bs-1via Agrobacteriumtumefaciens-mediated transformation (ATMT). Based on analyses of fluorescenceexpression, PCR verification, genetic stability, growth parameters, and metabolism ofextra cellular enzymes, a transformed strain Bs-GFP that resembled its wild-typestrain, was chosen to investigate infection of B. sorokiniana on roots and leaves of thewheat cultivar Aikang58. Bright green fluorescence was observed in hyphae andconidia of the transformant Bs-GFP. The amplification of the diagnostic bands withthe gene-specific markers indicated that gfp was integrated into the genome of B.sorokiniana. Analyses of genetic stability and growth parameters demonstrated thatgfp was inherited normally, and the growth rate and metabolism of extracellularenzymes were comparable to the wild type strain. The GFP-labeled strain Bs-GFPwas able to incite symptoms on both underground and upperground parts of wheatplants, and the quantities of colonization (in terms of colony forming unit) in rootsand basal stem tissues of wheat plants by Bs-GFP was similar as those by Bs-1. At theinocation of fungus, the colonization of fungus at apex and meri-region in root waslittle. As the time of inoculation going, spores and hyphae were emerged inside root.The fungus inside root mainly concentrated in intercellular space and also less amountof the gungus ran across some cells by breaking into them. There was no colonizationof hyphae in some lesion which color was heavy; however, a great quantity of gunguswere observed on the lesions of leaf, interfelting reticulation.The results of transmission electron microscope (TEM) showed thatmitochondria in root were of degradation largely at the early stage of fungus infection.At the same time, when the gungus grown fast, the mitochondria were produced at alarge amount, providing energy for pathogenic bacteria. In the tissues of leaf, thestructure of chloroplast were varied and unnormal, and the plasmolysis phenomenonwere happened severely. A many qualities of mitochondria and chloroplast weredegradation and cells being to dead. The B. sorokiniana strain expressing GFPobtained via ATMT can be used to directly monitoring infection and colonization ofthe fungus on wheat. The results from this study will facilitate better understandinteractions between B. sorokiniana and wheat, as well other cereal crops.