RICE LIPID TRANSFER PROTEIN (LTP) GENES BELONG TO A COMPLEX MULTIGENEFAMILY AND ARE DIFFERENTIALLY REGULATED

Several cDNA clones encoding three different lipid transfer proteins ( LTPs) have been isolated from rice (Oryza sativa L.) in order to analy se the complexity, the evolution and the expression of the LTP gene fa mily. The mature proteins deduced from three clones exhibited a molecu lar mass of 9 kDa, in agreement with the molecular mass of other LTPs from plants. The clones were shown to be homologous in the coding regi on, while the 3' non-coding regions diverged strongly between the clon es. The occurrence of at least three small multigene families encoding these proteins in rice was confirmed by Southern blot analysis. When compared with each other and with LTPs from other plants, the cluster including rice LTPs and other cereal LTPs indicated that these genes d uplicated rather recently and independently in the different plant phy la. The expression pattern of each gene family was also investigated. Northern blot experiments demonstrated that they are differentially re gulated in the different tissues analysed. Components such as salt, sa licylic acid and abscisic acid were shown to modulate Ltp gene express ion, depending on tissues and gene classes, suggesting a complex regul ation of these genes. (C) 1997 Elsevier Science B.V.