The observation on infection structure differentiation of wheat stripe rust fungus in vitro.

The uredinial germination process of wheat stripe rust fungus Puccinia striiformis f. sp. tritici on leaf surface of the host plant, wheat, and non-host plant, rice, and on the surface of wheat spike and stem was observed by fluorescence microscope and scanning electron microscope. The observation shows that after urediospores germinated and formed germ tube, a series of infection structures such as substomatal vesicle, infection hypha and haustorial mother cells were formed on the wheat leaf surface. The differentiation of haustorial mother cells could be found on the surface of glume, lemma, palea and stem of wheat. On rice leaf surface, the infection structure differentiation of the rust fungus could also occur. The observation by fluorescence staining revealed that no obvious difference was found of the differentiation of infection structures of the wheat stripe rust fungus between in vitro and in plant tissue.