|
Gurney
A. L., Grimanelli D., Kanampiu F., Hoisington D., Scholes J. D.,
Press M. C. (2003) Novel sources of resistance to Striga
hermonthica in Tripsacum dactyloides, a wild relative
of maize. New Phytologist 160: 557-568
Summary
-
The
parasitic weed Striga hermonthica lowers cereal yield
in small-holder farms in Africa. Complete resistance in
maize to S. hermonthica infection has not been
identified. A valuable source of resistance to S.
hermonthica may lie in the genetic potential of wild
germplasm.
-
The
susceptibility of a wild relative of maize, Tripsacum
dactyloides, and a Zea mays-T.
dactyloides hybrid to S. hermonthica infection
was determined. S. hermonthica development was
arrested after attachment to T. dactyloides. Vascular
continuity was established between parasite and host but
there was poor primary haustorial tissue differentiation on T.
dactyloides compared with Z. mays. Partial
resistance was inherited in the hybrid.
-
Striga
hermonthica attached to Z. mays was manipulated
such that different secondary haustoria could attach to
different hosts. Secondary haustoria formation was inhibited
on T. dactyloides, moreover, subsequent haustoria
formation on Z. mays was also impaired.
-
Results suggested that T. dactyloides produced
a signal that inhibited haustorial development: this signal
may be mobile within the parasite haustorial root system.
Key
words: Tripsacum dactyloides, Striga hermonthica,
parasitic plants, wild relatives, plant resistance, haustorium.
|
