ToxA - Tsn1 Interaction for Spot Blotch Susceptibility in Indian Wheat: An Example of Inverse Gene-for-Gene Relationship
The - system is an example of an inverse gene-for-gene relationship. The gene encodes a host-selective toxin (HST) which functions as a necrotrophic effector and is often responsible for the virulence of the pathogen. The genomes of several fungal pathogens (e.g., and ) have been shown to carry the...
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Published in | Plant disease Vol. 104; no. 1; p. 71 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
01.01.2020
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Subjects | |
Online Access | Get more information |
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Summary: | The
-
system is an example of an inverse gene-for-gene relationship. The gene
encodes a host-selective toxin (HST) which functions as a necrotrophic effector and is often responsible for the virulence of the pathogen. The genomes of several fungal pathogens (e.g.,
and
) have been shown to carry the
gene.
is a sensitivity gene in the host, whose presence generally helps a
-positive pathogen to cause spot blotch in wheat. Cultivars lacking
are generally resistant to spot blotch; this resistance is attributed to a number of other known genes which impart resistance in the absence of
. In the present study, 110 isolates of
strains, collected from the ME
A and ME
C megaenvironments of India, were screened for the presence of the
gene; 77 (70%) were found to be
positive. Similarly, 220 Indian wheat cultivars were screened for the presence of the
gene; 81 (36.8%) were found to be
positive. When 20 wheat cultivars (11 with
and 9 with
) were inoculated with
-positive isolates, seedlings of only those carrying the
allele (not
) developed necrotic spots surrounded by a chlorotic halo. No such distinction between
and
carriers was observed when adult plants were inoculated. This study suggests that the absence of
facilitated resistance against spot blotch of wheat. Therefore, the selection of wheat genotypes for the absence of the
allele can improve resistance to spot blotch. |
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ISSN: | 0191-2917 1943-7692 |
DOI: | 10.1094/PDIS-05-19-1066-RE |