Differential Expression of Rice Lipid Transfer Protein Gene (LTP) Classes in Response to Abscisic Acid, Salt, Salicylic Acid, and the Fungal Pathogen Magnaporthe grisea

Rice lipid transfer protein (LTP) genes belong to a complex multigene family and are differentially regulated. The organ specificity of expression for the different classes of rice LTP gene Subfamily I was investigated here. LTPC1 (Class I) was highly expressed in flowers and stems, while LTPC2 (Class II) showed higher expression in leaves and stems. LTPC3 (Class III) showed higher expression in stems, whereas corresponding mRNA was barely detected in leaves. Treatment of 3-wk-old plants with ABA induced the expression of LTPC1 and LTPC3 after 1 d. Expression of all three LTP isoforms was induced in response to salicylic acid. Because some of these genes are reportedly induced by pathogens, we also investigated whether they might be responsive to infection by Magnaporthe grisea. Transcripts of LTPC1 started to accumulate in the leaves at 8 h after incompatible inoculation, reaching a maximum level at 48 h. In contrast, the response was much slower and weaker after compatible inoculation.