Abstract

Lysophosphatidyl acyltransferase (LPAAT) is a pivotal enzyme controlling the metabolic flow of lysophosphatidic acid into different phosphatidic acids in diverse tissues. The functions of LPAAT genes have been intensively studied in Arabidopsis, but not in peanut (Arachis hypogaea L.). In this study, conventional RT-PCR or RACE (rapid amplification of cDNA ends)-PCR were used to clone four AhLPAAT genes from peanut. Quantitative real-time RT-PCR analysis indicated that AhLPAAT2 transcript was more abundant in seeds, whereas the transcript abundances of other three genes were higher in flowers than in other tissues examined. During seed development, levels of AhLPAAT6 transcripts decreased, whereas levels of other three transcripts remained relatively high at the initial stages of seed development but dramatically decreased in abundance during later stages. Expression analysis of four genes under conditions of cold, salt, drought and ABA stresses indicated that AhLPAAT transcripts were differentially regulated during abiotic stresses. Transcripts of the four genes increased substantially in leaves exposed to drought stress. Levels of AhLPAAT2 transcript were distinctly enhanced after exposure to cold, salt and drought stresses, whereas AhLPAAT4 was obviously up-regulated after salt, drought and ABA treatments. The expressions of AhLPAAT6 increased in all materials after stress treatments except for salt-stressed leaves, whereas transcript levels of AhLPAAT5 only increased in cold- and drought-stressed leaves and ABA-treated roots. These insights into peanut LPAATs may facilitate modification of oil deposition and improvement of abiotic stress resistance in this important crop.