Molina Fernández, Antonio and García Olmedo, Francisco
Expression of genes encoding thionins and lipid-transfer proteins. A combinatorial model for the responses of defense genes to pathogens..
In: "VIIth NATO Advanced Study Institute on Molecular Biology. Molecular Genetic Analysis of Plant Development and Metabolism", 09/05/1993-19/05/1993, Mallorca, España. ISBN 978-3540577331.
Seeds normally accumulate high levels of proteins that are either toxic or inhibitory towards heterologous systems, including pathogens, pests and predators. This is the case of cereal kernels, where a substantial fraction of the non-storage proteins is represented by different families of these proteins (for reviews, see Garcia-Olmedo et al.1989, 1992). The same types of proteins are often present in other tissues, either under normal development or under stress, including infection by pathogens. The thionins (THs) and the so-called non-specific lipid transfer proteins (LTPs) are two such families. Thionins were first reported in wheat endosperm (Balls et al., 1942) and their in vitro antipathogenic properties have been known for over 2 0 years (Fernadez de Caleya et al. 1972), while cereal LTPs were first reported in barley aleurone (Mundy and Rogers 1986) and we have recently shown that different members of this family can be isolated from other barley tissues and that they are potent growth inhibitors of bacterial and fungal plant pathogens (Molina and Garcia-Olmedo, 1991; Molina et al.1993; Molina and Garcia- Olmedo, submitted). In this report, we will update our knowledge of the molecular biology and inhibitory properties of barley THs and LTPs, and will describe the developmental and pathogeninduced expression of the different genes encoding these proteins. Also, a working model for the response of defense genes against infection by different pathogens will be proposed.