Uromyces appendiculatus
is a major pathogen on common bean. Like other rust fungi, it uses effectors to influence its host plant. Effectors are assumed to possess characteristic expression profiles, reflecting their activity during the infection process. In order to determine expression profiles using RT-qPCR, stably expressed reference genes are necessary for normalization. These reference genes need to be tested. Using samples representing seven different developmental stages of the urediospore-based infection process we employed RT-qPCR to measure the expression of 14 candidate reference genes and determined the most suitable ones based on the range of Cq values and comparative calculations using the geNorm and NormFinder algorithms. Among the tested genes
RPS14
had the smallest Cq range, followed by
Elf1a
and
Elf3
; geNorm rated
Tub
and
UbcE2
best with
CytB
as a third and NormFinder found
UbcE2
,
Tub
and
Elf3
as best reference genes. Combining these findings using equal weight for the rankings
UbcE2
,
Elf3
and
Tub
can be considered the best reference genes. A combination of either two reference genes,
UbcE2
and
Tub
or three reference genes,
UbcE2
,
Tub
, and
Elf3
is recommended for normalization. However, differences between most genes were relatively small, so all tested genes can be considered suitable for normalization with the exception of
RPS9
,
SDH
,
Ubc
and
PDK
.