Reference "Differential defense reactions in leaf tissues of barley in response to infection by Rhynchosporium secalis and to treatment with a fungal avirulence gene product"

Reference ID

8686

Title

Differential defense reactions in leaf tissues of barley in response to infection by Rhynchosporium secalis and to treatment with a fungal avirulence gene product

Source

Molecular plant-microbe interactions : MPMI, 2003, vol. 16, pp. 893-902

Authors (7)

Steiner-Lange-S	Fischer-A
Boettcher-A	Rouhara-I
Liedgens-H	Schmelzer-E
Knogge-W

Abstract

Expression of defense-associated genes was analyzed in leaf tissues of near-
isogenic resistant and susceptible barley cultivars upon infection by
Rhynchosporium secalis. The genes encoding pathogenesis-related (PR) proteins
PR-1, PR-5, and PR-9 are specifically expressed in the mesophyll of resistant
plants, whereas a germin-like protein (OxOLP) is synthesized in the epidermis
irrespective of the resistance genotype. Restriction-mediated differential
display was employed to identify additional epidermis-specific genes. This
resulted in the detection of another PR gene, PR-10, along with a lipoxygenase
gene, LoxA, and a gene of unknown function, pI2-4, which are specifically
induced in the epidermis of resistant plants. The gene encoding a putative
protease inhibitor, SD10, is preferentially but not exclusively expressed in the
epidermis. The fungal avirulence gene product NIP1 triggers the induction of the
four PR genes only. At least two additional elicitors, therefore, must be
postulated, one for the unspecific induction of OxOLP and one for the resistance-
specific induction of LoxA, pI2-4, and SD10. PR-10 expression can be assumed to
be the consequence of NIP1 perception by epidermis cells. In contrast, gene
expression in the mesophyll is likely to be triggered by an as yet unknown
signal that appears to originate in the epidermis and that is strongly amplified
in the mesophyll.