Brown-rot wood decay--insights gained from a low-decay isolate of Postia placenta

Mechanism of Brown-Rot Decay B r o w n r o t F u n g i r e p r e s e n t o n e o f t h e m o s t economically important groups of wood decay micmorganisms. Some accounts estimate that as high as 80% of all in-service wood decay is c a u s e d b y b r o w n r o t F u n g i . cur ran t wood preservatives protect wood by means of broad spectrum biocides. Understanding the precise mechanism of brown-ro t decay would permi t development of targeted wood preservatives. A non-degradative s t r a i n O f P o s t i a p l a c e n t a (ME-20) was studied to obtain information on defects in key decay mechanisms which prevent co loniza t ion . w e i g h t l o s s a n d h y d r o l y s i s o f wood components, e s p e c i a l l y c e l l u l o s e . T h e major defects of the monokaryon strain ME-20 are: 1 ) non-accumula t ion of oxa l ic ac id on ce l lu lose and wood; 2 ) n o n f i b r i l l a r h y p h a l s h e a t h : 3 ) F a i l u r e t o t r a n s l o c a t e i r o n i n t o wood in so i l b lock tes t s ; and 4) Inab i l i ty to degrade pit membranes. The Failure to produce o x a l i c a c i d i n t h e p r e s e n c e o f p e c t i n o r c e l l u l o s e o r t o d e g r a d e c e l l u l o s e ( w o o d o r c o t t o n ) a p p e a r t o b e k e y c h a r a c t e r i s t i c s o f this nondegradative isolate.