Submitted to: Book Chapter
Publication Type: Book / chapter
Publication Acceptance Date: 12/15/2003
Publication Date: 4/20/2004
Citation: Barrow, J.R., Aaltonen, R.E. 2004. A staining method for systemic endophytic fungi in plants. In: Lartey, R.T., Caesar A.J., editors. Emerging Concepts in Plant Health Management. Kerala, India: Research Signpost p. 61-67. Interpretive Summary: Fungi are microscopically distinguished from plant cells by their distinct, thread-like form and by specific components of their walls that specifically stain with biological stains. We developed an analytical method for identifying unique symbiotic fungal structures in native plant tissues. This method reveals atypical fungal structures that have escaped detection using conventional fungus staining methods. A histochemical stain revealed that these fungi assimilate extensive quantities of host carbon. Their potential ecological role is to assimilate, transport, store and utilize plant carbon for enhanced drought tolerance in arid environments.
Technical Abstract: Native desert plants are extensively colonized by dark septate fungal endophytes (DSE). These are characterized by stained or pigmented hyphae and microsclerotia growing inter- and intra-cellularly within the root cortex. A dual-staining method was developed using trypan blue that targets fungal chitin and sudan IV that targets internal fungal lipid bodies. Roots and leaves of dominant grasses and shrubs of arid southwestern rangeland were dual-stained to determine the nature and extent of colonization by DSE fungi. Fungal structures ranged from lipid bearing protoplasts, hyaline, stained and melanized hyphae and microsclerotia. They inhabit the apoplastic spaces of roots and shoots. Predominant fungal structures are protoplasts in physiologically active tissues that are identified with stained, associated lipid bodies. This method shows colonization by DSE fungi is more extensive than was previouisly throught.