The Haustoria of Certain Rusts and the Relation Between Host and Pathogene

Development of Haustorium in <i>Taphrina maculans</i> Butler

“…The nuclear deformity suggests furtherance of food absorption as the purpose of contact with the nucleus. This observation is at variance with those by Rice (1927) reporting healthy condition of the host nuclei attacked by Puccinia sorghi.…”

“…The infected cells become discolored after some time, but the chlorophyll in the cells around the spot is retained longer forming a green island. Similar green islands have been reported in several rust infections (Rice 1927) and are considered an illustration of longer life imparted to infected host cells under adverse conditions. Their development in turmeric leaves indicates tendencies of T. maculans towards mutualism rather than complete parasitism.…”

“…The haustorium is hyaline in the beginning but changes to pale amber yellow with maturity. Members of Peronosporales (Fraymouth 1956), Erysiphales (Smith 1900) and Uredinales (Rice 1927) develop branched haustoria, but none is reported to possess a multiple dichotomously branched haustorium as in T. maculans. Morphologically it has attained a new form not duplicated in any other fungus species.…”

“…27, 28). Rice (1927) stated that the host nucleus did not show any abnormality due to the haustorial contact in Puccinia sorghi Schw. ; abnormalities observed by her in few of the nuclei were not due to the fungal attack as they occurred in healthy condition also.…”

“…Allen (1928) observing as many as 82% haustorium: host nucleus contacts in Puccinia striiformis West . suggested a definite affinity between the 2 organelles, although Rice (1935) believed it a variable phenomenon . The question as to which of these members initiated such a contact has remained controversial .…”