Molecular cloning and functional analyses of the salt- responsive gene KVHSP70 from Kosteletzkya virginica

Land degradation resulting from soil salinization is becoming a growing menace in almost all over the world. The degraded soil shows poor performance in water conductance and soil aeration, which threatens plant growth and development. Therefore, to discover the resistance genes and breed plant with stress tolerance are necessary. The modern molecular biotechnology makes the plant with enhanced adaption possible. To do this, KvHSP70 with 1950 bp open reading frame (ORF) from Kosteletzkya virginica was isolated, studied, and transformed into tobacco for functional study. Our research showed that it encodes a typical HSP70 protein with 649 amino acids and it could be induced by salt, high temperature, drought, and abscisic acid (ABA). The transgenic tobacco with it overexpression had higher chlorophyll content, less electrolyte leakage, lower water potential and increased proline content under salt stress. Meanwhile, the transgenic acquired superior antioxidant enzyme activities and decreased MDA content. All results highlight the significance of the new found gene in breeding salt resistant plants with molecular manipulation. Hence, K. virginica provides us with helpful information and gene resources to culture new variety adapted to salt-affected soil and available for land rehabilitation perhaps in the future.