Differential expression of distinct soybean resistance genes interacting with Argentinean isolates of Diaporthe phaseolorum var. meridionalis

• Published in: European journal of plant pathology Vol. 135; no. 2; pp. 351 - 362
• Main Authors: Chiesa, María A., Pioli, Rosanna N., Cambursano, Mariana V., Morandi, Eligio N.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-02-2013; Springer Nature B.V
• Subjects: Agriculture; Biomedical and Life Sciences; Diaporthe phaseolorum; Ecology; Fungi; Gene expression; Genotypes; Life Sciences; Physiology; Plant diseases; Plant Pathology; Plant resistance; Plant Sciences; Soybeans; resistance genes; Incomplete penetrance
• ISSN: 0929-1873; 1573-8469
• DOI: 10.1007/s10658-012-0091-5

Soybean Stem Canker (SSC), caused by
Diaporthe phaseolorum
var.
meridionalis
(
Dpm
), is an important disease of soybean in Argentina. There are five known dominant genes that confer resistance to SSC,
Rdm1
to
Rdm5
. Particularly,
Rdm2
was identified in cv. Tracy-M and then it was stabilized in the breeding line T2. The
Rdm4
gene was first identified in cv. Hutcheson. More recently it was found that this gene was linked to the
Rdm5
gene, defining the
Rdm4-5
resistance region in Hutcheson. The objective of this work was to analyze the behaviour of the dominant
Rdm2, Rdm4
and
Rdm5
genes interacting with the CE109 and CE112 local physiological races of
Dpm
, in different susceptible backgrounds (genotypes RA702 and J77-339).
Rdm4
and
Rdm5
segregated phenotypically as completely dominant genes in the specific interactions with the CE109 and CE112 isolates, respectively, in both susceptible backgrounds. Similarly,
Rdm2
segregated as expected for a complete dominant gene in the specific interaction with the CE109 isolate, in both susceptible backgrounds. However, when interacting with the CE112 isolate, the
Rdm2
gene did not segregate as expected for a completely dominant gene, neither in RA702 nor in J77-339 susceptible background. The distorted segregation of the
Rdm2
gene was due to incomplete penetrance. To the best of our knowledge this is the first report documenting changes in the degree of penetrance of a soybean resistance gene (
Rdm2
) depending upon the physiological race of
Dpm
which interacts with and the genetic background in which the
Rdm
gene is being expressed.