Pathogen‐inducible Ta‐Lr34res expression in heterologous barley confers disease resistance without negative pleiotropic effects
Year:2018
Bibliography
Boni R, Chauhan H, Hensel G, Roulin A, Sucher J, Kumlehn J, Brunner S, Krattinger SG† and Keller B† (2018) Pathogen-inducible Ta-Lr34res expression in heterologous barley confers disease resistance without negative pleiotropic effects. Plant Biotechnology Journal 16, 245-253.
Abstract
Plant diseases are a serious threat to crop production. The informed use
of naturally occurring disease resistance in plant breeding can greatly
contribute to sustainably reduce yield losses caused by plant
pathogens. The Ta‐Lr34res gene encodes an ABC transporter
protein and confers partial, durable, and broad spectrum resistance
against several fungal pathogens in wheat. Transgenic barley lines
expressing Ta‐Lr34res showed enhanced resistance against powdery mildew and leaf rust of barley. While Ta‐Lr34res is only active at adult stage in wheat, Ta‐Lr34res
was found to be highly expressed already at the seedling stage in
transgenic barley resulting in severe negative effects on growth. Here,
we expressed Ta‐Lr34res under the control of the pathogen‐inducible Hv‐Ger4c
promoter in barley. Sixteen independent barley transformants showed
strong resistance against leaf rust and powdery mildew. Infection assays
and growth parameter measurements were performed under standard
glasshouse and near‐field conditions using a convertible glasshouse. Two
Hv‐Ger4c::Ta‐Lr34res transgenic events were analysed in
detail. Plants of one transformation event had similar grain production
compared to wild‐type under glasshouse and near‐field conditions. Our
results showed that negative effects caused by constitutive high
expression of Ta‐Lr34res driven by the endogenous wheat
promoter in barley can be eliminated by inducible expression without
compromising disease resistance. These data demonstrate that Ta‐Lr34res
is agronomically useful in barley. We conclude that the generation of a
large number of transformants in different barley cultivars followed by
early field testing will allow identifying barley lines suitable for
breeding.