The non-specific lipid transfer protein GmLtpI.3 is involved in drought and salt tolerance in soybean

Plant non-specific lipid transfer proteins (nsLTPs/LTPs) play important roles in plant growth, development and abiotic stress responses. However, little is known about LTPs in soybean. In this study, 131 LTPs were identified and divided into ten types (I, II, III, IV, V, VI, VII, VIII, IX, and Y), and each GmLtp has the characteristic eight-cysteine motif (8 CM) of plant LTPs. RNA-seq data showed that most GmLtps responded to a variety of abiotic stresses. Among the GmLtp members, GmLtpI.3 was significantly induced under drought and salt treatments. Overexpressing GmLtpI.3 improved tolerance to drought and salt stresses in transgenic Arabidopsis and soybean. The results showed that the accumulation of reactive oxygen species (ROS) in the roots of GmLtpI.3-over-expressing (OE-GmLtpI.3) plants decreased significantly, compare with GmLtpI.3 RNA interference (RNAi-GmLtpI.3) and empty vector (EV-Control) plants. Furthermore, compared with EV-Control, the expression level of GmSOD1 and GmSOD2 increased in OE-GmLtpI.3. Contrarily, the expression of GmRBOHA and GmRBOHB decreased in OE-GmLtpI.3. The results of this study provide the basis for further comprehensive analyses of LTP genes and insights into abiotic stress response mechanisms in soybean.