Overexpression of a cotton nonspecific lipid transfer protein gene, GhLTP4, enhances drought tolerance by remodeling lipid profiles, regulating abscisic acid homeostasis and improving tricarboxylic acid cycle in cotton

Abstract

Drought is a major abiotic stress that causes severely crop yield loss worldwide. Lipid transfer proteins (LTPs) play an essential role during plant growth and cell signaling transduction associated with stress responses. However, the regulatory circuits involved in drought stress remain largely unresolved. Here, we reported that a nonspecific lipid transfer protein, namely GhLTP4 , positively modulated drought stress tolerance in cotton. GhLTP4 (synonym Pfs6 , GenBank: ABO42261) was preferentially expressed in fiber cells, while, it was also strongly induced by phytohormone abscisic acid (ABA) and drought stress treatments. Compared with wild type, over- and down-expression of GhLTP4 in cotton led to the increased and decreased drought tolerance, respectively. Overexpression of GhLTP4 remarkably increased lipid components and the accumulation of culticular waxes in transgenic cotton leaves under normal condition. Under drought stress, GhLTP4 -overexpressing transgenic cotton exhibited the remodeled lipid profiles, more ABA contents, and the improved tricarboxylic acid cycle process. Taken together, we reveal the function and underlying mechanisms of GhLTP4 in regulating cotton drought tolerance and create valuable genetic accessions for cotton drought-tolerant breeding. • Overexpression of GhLTP4 enhances significantly cotton drought tolerance. • Overexpression of GhLTP4 alters the lipid profiles of cotton leaf tissue. • Overexpression of GhLTP4 improves the drought tolerance by remodeling lipid profiles and ABA homeostasis. • Overexpression of GhLTP4 promotes tricarboxylic acid metabolism under drought stress.