At the maize/Agrobacterium interface: natural factors limiting host transformation.
At the maize/Agrobacterium interface: natural factors limiting host transformation.
复制标题
DOI：
10.1016/s1074-5521(00)00007-7
复制
发表时间：
2000-08
影响因子：
--
通讯作者：
Jin Zhang;Laural Boone;R. Kocz;Chuhan Zhang;A. Binns;David G. Lynn
中科院分区：
文献类型：
--
作者：
Jin Zhang;Laural Boone;R. Kocz;Chuhan Zhang;A. Binns;David G. Lynn
Background:Agrobacterium tumefacienshas been successfully harnessed as the only natural vector for the incorporation of foreign genes into higher plants, but its use in the grain crops is often limited. Low transformation efficiency has been partly attributed to a failure in the initial events in the transformation process, specifically in the capacity of the VirA/VirG two-component system to induce expression of the virulence genes.Results: Here we show that the root exudate ofZea maysseedlings specifically inhibits virulence gene expression, determine that 2-hydroxy-4,7-dimethoxybenzoxazin-3-one (MDIBOA), which constitutes >98% of the organic exudate of the roots of these seedlings, is the most potent and specific inhibitor of signal perception inA. tumefaciens-mediated gene transfer yet discovered, and develop a model that is able to predict the MDIBOA concentration at any distance from the root surface. Finally, variants ofA. tumefaciensresistant to MDIBOA-mediated inhibition ofvirgene expression have been selected and partially characterized.Conclusions: These results suggest a strategy in which a plant may resist pathogen invasion by specifically blocking virulence gene activation and yet ensure that the ‘resistance factor' does not accumulate to levels sufficient to impose toxicity and selection pressure on the pathogen. The data further establish that naturally occurring inhibitors directed against signal perception by the VirA/VirG two-component regulatory system can play an important role in host defense. Finally, selected variants resistant to specific MDIBOA inhibition may now be used to extend the transformation efficiency of maize and possibly other cereals.
