12 research outputs found
Naturally occurring broad-spectrum powdery mildew resistance in a Central American tomato accession is caused by loss of mlo function
The resistant cherry tomato (Solanum lycopersicum var.
cerasiforme) line LC-95, derived from an accession collected
in Ecuador, harbors a natural allele (ol-2) that confers
broad-spectrum and recessively inherited resistance to
powdery mildew (Oidium neolycopersici). As both the genetic
and phytopathological characteristics of ol-2–mediated
resistance are reminiscent of powdery mildew immunity
conferred by loss-of-function mlo alleles in barley and Arabidopsis,
we initiated a candidate-gene approach to clone Ol-
2. A tomato Mlo gene (SlMlo1) with high sequence-relatedness
to barley Mlo and Arabidopsis AtMLO2 mapped to the
chromosomal region harboring the Ol-2 locus. Complementation
experiments using transgenic tomato lines as
well as virus-induced gene silencing assays suggested that
loss of SlMlo1 function is responsible for powdery mildew
resistance conferred by ol-2. In progeny of a cross between
a resistant line bearing ol-2 and the susceptible tomato cultivar
Moneymaker, a 19-bp deletion disrupting the SlMlo1
coding region cosegregated with resistance. This polymorphism
results in a frameshift and, thus, a truncated nonfunctional
SlMlo1 protein. Our findings reveal the second
example of a natural mlo mutant that possibly arose postdomestication,
suggesting that natural mlo alleles might be
evolutionarily short-lived due to fitness costs related to loss
of mlo function
Naturally occurring powdery mildew resistance in a tomato accession is caused by loss of MLO function.
Homology-based cloning of the recessive gene ol-2 conferring broad-spectrum resistance to tomato powdery mildew
Naturally occurring broad-spectrum powdery mildew resistance in a central American tomato accession is caused by loss of Le MLO1 function.
The resistant cherry tomato (Solanum lycopersicum var.
cerasiforme) line LC-95, derived from an accession collected
in Ecuador, harbors a natural allele (ol-2) that confers
broad-spectrum and recessively inherited resistance to
powdery mildew (Oidium neolycopersici). As both the genetic
and phytopathological characteristics of ol-2–mediated
resistance are reminiscent of powdery mildew immunity
conferred by loss-of-function mlo alleles in barley and Arabidopsis,
we initiated a candidate-gene approach to clone Ol-
2. A tomato Mlo gene (SlMlo1) with high sequence-relatedness
to barley Mlo and Arabidopsis AtMLO2 mapped to the
chromosomal region harboring the Ol-2 locus. Complementation
experiments using transgenic tomato lines as
well as virus-induced gene silencing assays suggested that
loss of SlMlo1 function is responsible for powdery mildew
resistance conferred by ol-2. In progeny of a cross between
a resistant line bearing ol-2 and the susceptible tomato cultivar
Moneymaker, a 19-bp deletion disrupting the SlMlo1
coding region cosegregated with resistance. This polymorphism
results in a frameshift and, thus, a truncated nonfunctional
SlMlo1 protein. Our findings reveal the second
example of a natural mlo mutant that possibly arose postdomestication,
suggesting that natural mlo alleles might be
evolutionarily short-lived due to fitness costs related to loss
of mlo function