Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Echinobase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
Echinobase
ECB-ART-39646
Appl Environ Microbiol 1992 Mar 01;583:809-14. doi: 10.1128/aem.58.3.809-814.1992.
Show Gene links Show Anatomy links

Genetic Analysis of the Role of Phytoalexin Detoxification in Virulence of the Fungus Nectria haematococca on Chickpea (Cicer arietinum).

Miao VP , Vanetten HD .


Abstract
Chickpea (Cicer arietium L.) produces the antimicrobial compounds (phytoalexins) medicarpin and maackiain in response to infection by microorganisms. Nectria haematococca mating population (MP) VI, a fungus pathogenic on chickpea, can metabolize maackiain and medicarpin to less toxic products. These reactions are thought to be detoxification mechanisms in N. haematococca MP VI and required for pathogenesis by this fungus on chickpea. In the present study, these hypotheses were tested by examining the phenotypes of progeny from crosses of the fungus that segregated for genes (Mak genes) controlling phytoalexin metabolism. Mak1 and Mak2, two genes that individually confer the ability to convert maackiain to its 1a-hydroxydienone derivative, were linked to higher tolerance of the phytoalexins and high virulence on chickpea. These results indicate that this metabolic reaction is a mechanism for increased phytoalexin tolerance in the fungus, which thereby allows a higher virulence on chickpea. Mak3, a gene conferring the ability to convert maackiain to its 6a-hydroxypterocarpan derivative, also increased tolerance to maackiain in strains which carried it; however, the contribution of Mak3 to the overall level of pathogenesis could not be evaluated because most progeny from the cross segregating for this gene were low in virulence. Thus, metabolic detoxification of phytoalexins appeared to be necessary, as demonstrated in the Mak1 and Mak2 crosses, but not sufficient by itself, as in the Mak3 cross, for high virulence of N. haematococca MP VI on chickpea.

PubMed ID: 16348672
PMC ID: PMC195338
Article link: Appl Environ Microbiol


Genes referenced: LOC591372

References [+] :
Gardner, Construction & architects survey. 1989, Pubmed