Competition between Related Strains of Nodule Bacteria and Its Influence on Infection of the Legume Host

H. Nicol, H. G. Thornton
1941 Proceedings of the Royal Society of London. Biological Sciences  
T h e w o r k d e a ls w i t h t h e b e h a v io u r o f m ix e d s t r a i n s o f n o d u le b a c te r ia t o w a r d s e a c h o t h e r a n d to w a r d s t h e i r le g u m e h o s t. I t in t r o d u c e s t h e c o n c e p t o f d o m in a n c e in c o m p e t it io n b e tw e e n s tr a in s . T h is d o m in a n c e is i n d e p e n d e n t o f d e g re e o f e ff e c tiv e n e s s a s r e g a r d s n itr o g e n f i x a tio n . W h e r e tw o s t r a i n s o f n o d u le b a c t e r
more » ... i a a r e b o t h p r e s e n t in t h e s u r r o u n d in g s o f t h e i r h o s t 's r o o t s y s te m , a c ti v e c o m p e t it io n b e tw e e n t h e m m a y c a u s e t h e s t r a i n h a v i n g t h e h ig h e r in i t i a l g r o w th r a t e a lm o s t c o m p le te ly t o c h e c k m u l t i p l i c a t i o n o f t h e o t h e r s t r a i n o u ts id e t h e p l a n t . T h is d o m i n a n t s t r a i n w ill t h e n b e r e s p o n s ib le f o r n e a r l y a ll t h e n o d u le s . I n p e a s a n d s o y b e a n s , w h e r e g r o w th o f t h e r o o t s y s te m is r a p i d a n d o f c o m p a r a t i v e l y s h o r t d u r a t i o n , t h e n o d u le -p r o d u c in g c a p a c i t y o f t h e p l a n t m a y b e p a r t i a l l y o r w h o lly s a tis f ie d b y t h e n o d u le s p r o d u c e d w ith i n t h e fir s t fe w w e e k s , so t h a t f u r t h e r in f e c tio n , w h e th e r b y t h e s a m e o r b y a d if fe re n t s t r a i n , is c h e c k e d o r in h i b it e d . I n c lo v e r , w h o s e r o o t s y s te m c o n tin u e s t o g ro w o v e r a lo n g p e rio d , t h e f ir s t -f o r m e d n o d u le s d o n o t s t o p f u r t h e r n o d u le s f r o m b e in g f o r m e d e ith e r b y t h e s a m e o r b y a d if f e r e n t s t r a i n . T h e r e a r e la r g e d iffe re n c e s in t h e r a t e s o f a p p e a r a n c e a n d fin a l n u m b e r s o f n o d u le s p r o d u c e d b y d if f e r e n t s t r a i n s s u p p lie d i n p u r e c u lt u r e , p a r t i c u la r ly w i t h c lo v e r . T h e r e l a t i v e n u m b e r s o f n o d u le s p r o d u c e d b y t h e tw o s t r a in s s im u l ta n e o u s l y a p p li e d t o t h e r o o t s is c o n d itio n e d b y t h e sp e c ific in f e c tiv ity p e c u li a r t o e a c h s t r a i n , u n le s s s o m e o t h e r f a c t o r , s u c h a s c o m p e t it io n o u ts id e t h e p l a n t , m a s k s t h i s e ffe c t.
doi:10.1098/rspb.1941.0003 fatcat:m7tdyi7y6bc5tasouaycbpzzd4